The Quill

An Adventure System for the 48k Spectrum by Gilsoft © 1983

The Quill - download [QUILL.tap] for use with a ZX Spectrum emulator.

Contents

What is Adventure?

Adventure can be described as a computerised version of the game Dungeons & Dragons. In Dungeons & Dragons one person is nominated as the dungeon master, and he invents a dungeon for other players to explore and try to retrieve hidden treasures which are usually protected by monsters of various shapes and sizes. Each player notifies his proposed actions to the dungeon master who decides on the outcome, sometimes with the help of dice to introduce a random element.

In Adventure the computer takes the place of the dungeon master and the player or players explore a predefined dungeon. Most Adventures will contain a vocabulary of words which the computer 'understands', a variety of locations which a player may wander around and objects which have to be used in the correct way to enable the Adventure to be solved. The computer will describe a situation to the player and invite him to decide on a course of action. The computer then tells the player the result of his action.

Everyone who plays Adventure has the problem of making the computer understand their commands The computer will only have a limited vocabulary of perhaps a few hundred words and 'finding the right words' can sometimes he a problem, for example, if you are playing Dungeons & Dragons and the dungeon master tells you “There is a lamp nearby” then if you decide to “PICK UP THE LIGHT” the dungeon master should know what you mean. If the same situation occurs when playing Adventure the computer may understand “GET LAMP” but may not know that LIGHT means, on this occasion, the same as LAMP or that PICK UP means the same as GET. Even so, most players will very quickly get the knack of 'finding the correct words'. However, it should be noted that it is up to the Adventure designer to decide which words are included in the computer's vocabulary.

Getting Started

The Quill Adventure system is made up of three parts:-

a)  A database which will contain all the information relevant to an adventure
b)  A database Editor which enables data to be inserted into, amended in or deleted from the database..,
c)  An Interpreter (this is the dungeon master) which uses the data in the database to execute your adventure.

To load The Quill use LOAD ””. The introductory screen will tell you the address of the User Defined Graphics (UDG's) and you should make a note of this as you will need it if you ever want to change them.

Part 1 of this manual will introduce you gently to The Quill, from simple location descriptions through to complex condition tests and actions. It is strongly recommended that you work all the way through Part 1 before attempting to write your own adventures. Part 2 contains a detailed description of The Quill for reference.

Part 1

The Main Menu

When The Quill has loaded you will be presented with the Editor's Main Menu which gives you a number of options. Some of these options e.g. Bytes Spare, will perform a function and return to the Main Menu while others e.g. Location Text, will give you a sub menu. The RETURN TO BASIC option is an exception to this as it executes the BASIC NEW command which destroys The Quill.

The Input Routine

The input routine used in the Editor is very similar to the BASIC 'INPUT LINE' routine and the keyboard responds in exactly the same way. In particular you should note that CAPS SHIFT 1 will clear the input buffer while CAPS SHIFT 6 gives the error message 'STOP in INPUT'. Try typing in a few characters and then pressing CAPS SHIFT 1 then type in a few more characters and press CAPS SHIFT 6. Error messages appear at the bottom of the screen in a similar way to BASIC's error messages and pressing any key will return you to a menu.

Whenever you press ENTER the Editor checks that what you have typed in is valid i.e. it checks the syntax. If the Editor finds a syntax error it is indicated, in the same way as BASIC, by a flashing ? following the error. However, unlike BASIC, the Editor positions the cursor immediately after the flashing ? so that the cursor is in the vicinity of the error. On the Main Menu the only valid options are single capital letters in the range A to Q and the copyright symbol. Try typing in 3 and pressing ENTER, then delete the 3 and type in ABC followed by ENTER. In each case a syntax error will be detected. Note that the lower case letters a to q will also give a syntax error but the Editor will place the cursor in C mode i.e. CAPS LOCK, whenever a menu is displayed.

Bytes Spare

Let's now try one of the options on the Main Menu. If you clear the input buffer (CAPS SHIFT 1), then type O for Bytes Spare and press ENTER you will get a display which tells you how many bytes are unused in the database and the address at which they start. The start address is only of use if you are writing an adventure to fit into a 16K Spectrum. If the spare bytes start before 32769 the adventure will run in a 16K machine.

Permanent Colours

When The Quill is loaded it behaves as if the BASIC command INK 9: PAPER 1: BORDER 1: FLASH 0: BRIGHT 0: INVERSE 0: OVER 0 had been executed. The values of INK, PAPER & BORDER can be changed by selecting option Q on the Main Menu. Note that CAPS SHIFT 6 can be used at any time to return to the menu. INK 9 (i.e. contrast) is recommended. Try changing the colours and in particular try having different BORDER & PAPER colours as some people find this helpful. All of the messages in this section e.g. Input INK (0-9), are printed with blue paper and white ink. Try changing INK & PAPER to the same value and you will realise why. Just remember that 'Permanent Colours' is still option Q on the Main Menu even if you can't see the menu.

Save, Verify & Load Database

These three options on the Main Menu allow the database to be saved to or reloaded from tape and in each case you will be prompted to “Type in name of file”. When loading or verifying, the Spectrum will search for a file of bytes with the name specified and then load or verify it. If you enter a null filename i.e. just press ENTER, the Spectrum will load or verify the first file of bytes it finds on the tape. However, when saving, a null filename will produce the error message Invalid file name. Care should be taken when using Load Database with a null filename because it does the equivalent of the BASIC command LOAD “” CODE i.e. it will load any file of bytes. The BREAK key may be used to interrupt a save, verify or load but if it is used to interrupt a load, or a Tape Error is detected during a load, then the database will be corrupt. Be very careful with a corrupt database as it can easily cause the Editor & Interpreter to become corrupt. In fact the only safe Editor command with a corrupt database is Load Database and this should be used until a database is loaded successfully.

Setting up an Adventure

The following sections of Part 1 of this manual will give you some practical experience of using The Quill to set up an adventure. Each section depends on entries having been made to the database in earlier sections so you have to work through it step by step. If you wish to break off part of the way through, please save the database to tape so that you can continue later where you left off.
A map of the mini adventure we are going to set up is shown in figure 1 and the objective of the adventure is to find the jewel and place it in the Dining Room. The map shows all of the locations in the adventure and how they are interconnected. The locations have all been given a location number, which is shown in the corner, and the position of various objects is indicated.

Before we start to set up the adventure make sure that the database is in the state it was when The Quill was loaded. The PAPER and BORDER colours should be set to 1 and INK should be set to 9 (contrast).

The Location texts

The descriptions we will use for each location are as follows:-

Location 0
I am in a Hall. The Kitchen is to the East, the Bedroom to the West and the Lounge to the South. Steps lead Down to the Cellar.

Location 1
I am in the Kitchen. The Hall is to the West and the Dining room is to the South.

Location 2
I am in the Dining Room. The Kitchen is to the North and the Lounge to the West.

Location 3
I am in the Lounge. To the North is the Hall while the Dining Room is to the East.

Location 4
I am in the Bedroom. The Hall is to the East and a bed is against the North wall.

Location 5
I am in the Cellar. Steps lead Up to the Hall.

If you type in C on the Main Menu the Location Text menu will be displayed and you will see that location texts can be Inserted, Amended or Printed. P is used to print on the screen while L is used to print on the printer. P or L by itself will start printing with the text for location 0. P and L can also be followed by a location number (locno.) and if that location exists printing will start with the text for that location. The P or L and the locno. must be separated by at least one space and if the locno. does not exist a syntax error will be detected.

Type in P followed by ENTER on the Location Text menu and you will see that a description is already present for location 0. The only reason for this is that the programming of The Quill was much simpler if location 0 was always present. The text that is present is not important but it does show some of the things that can be entered from the keyboard e.g. FLASH. Note that PAPER 0 and PAPER 6 have been used and that the use of INK 9 as a permanent colour has automatically changed the INK colour.

As a text is already present for location 0 we will have to amend it to the text required for our mini adventure. You will see from the Location Text menu that to amend a location text, A followed by a locno. must be entered. Please now enter A 0 and the existing text for that location will be copied to the input buffer and displayed at the bottom of the screen followed by a cursor. There are a number of points to be noted here. Firstly, because you are amending text, the Editor has changed the cursor to L mode i.e. lower case. Secondly, due to an inconsistency in the BASIC ROM, INK 9 behaves differently in the bottom of the screen and the INK colours are not changed as you would expect. The third point to note is that each line of the text ends with a CHR$ 6 to reduce the amount of memory that the text occupies. A CHR$ 6 behaves in the same way as a comma in a BASIC PRINT statement. If you now use CAPS SHIFT 5 and CAPS SHIFT 8 to move the cursor through the text you will see the effect of the CHR$ 6. Please now position the cursor at the beginning of the last line and then delete the CHR$ 6 at the end of the previous line using CAPS SHIFT 0. To reinsert the CHR$ 6 is a little awkward but it is worth the effort involved because it can considerably reduce the amount of memory used and it also makes moving the cursor through the text much easier. To insert a CHR$ 6, change the cursor to E (extended mode) by pressing CAPS SHIFT and SYMBOL SHIFT together, then press the 6 key to insert the control characters for PAPER 6 (i.e. CHR$ 17 and CHR$ 6). If you now use the delete key once you will delete the CHR$ 17 and leave the CHR$ 6. Experiment with the insertion of CHR$ 6 and try inserting multiple CHR$ 6's to create blank lines in the text.

Getting back to our mini adventure use CAPS SHIFT 1 to clear the input buffer and then type in the text we need for our location 0 i.e. the Hall. Use CHR$ 6 where appropriate and, if you like, put the compass directions in INVERSE. When you have typed it in press ENTER to amend the database. Note that the database is not amended until you press ENTER and that the use of CAPS SHIFT 6 at any time before pressing ENTER will leave the database unchanged.

The texts for the other locations in our mini adventure now have to be inserted by using the I option on the Location Text menu. Notice that the I is not followed by a locno. When you use l the Editor automatically allocates the next location number in sequence. Type in I followed by ENTER and the Editor will tell you which location number has been allocated (1 in this case) and display a cursor at the bottom of the screen. It is important that you realise that a null entry for the location number being inserted has already been made in the database and that if you were to use CAPS SHIFT 6 at this stage (do not do this now) the null entry would still remain.

Type in the text that we need for our location 1 and press ENTER which will change the null entry already inserted to the text you have typed in. You should now be able to insert the texts for locations 2 to 5 and then print them to check that they are correct. If you have made any mistakes then please amend the texts to correct the errors. You might also like to try P followed by a locno. e.g. P 2, to start printing with the text for location 2.

You should have inserted the location texts for locations 0 to 5 and returned to the Main Menu before continuing with the next part.

The Movements

The interconnections between our 6 locations can now be entered into the database and these are placed in the Movement Table. If you select D on the Main Menu the Movement Table menu will be displayed and you will see that entries can he amended or printed. Notice that entries cannot be inserted. This is because when you insert a location text for a location the Editor automatically creates a null entry for that location in the Movement Table. If you type in P on the Movement Table menu you should see that nulI entries do actually exist for our locations 0 to 5.

Refer back to the map of our mini adventure in figure 1 and you will see for location 0 that :-

EAST - goes to location 1
DOWN - goes to location 5
WEST - goes to location 4
SOUTH - goes to location 3.

Going back to the Movement Table menu type in A 0 to amend the entry for location 0. When 'Movements from location 0' is printed at the top of the screen, type in (exactly)

EST 1 DOWN 5 WEST 9 SOUTH 3 and press ENTER.

If you did type it in exactly you should get a syntax error after EST because it is not in the database's vocabulary. If you correct EST to EAST and press ENTER again you should get a syntax error after the 9 because the Editor knows that there is no location 9. Change the 9 to 4 and you should then have EAST 1 DOWN 5 WEST 4 SOUTH 3.

Pressing ENTER now will amend the existing database entry.

Now type in P on the Movement Table menu and you will see that the entry for location 0 reads :-

E TO 1
D TO 5
W TO 4
S TO 3

The Editor knows that E is a synonym of EAST (i.e. E means the same as EAST). D is a synonym of DOWN etc. and it always prefers to use the abbreviation or shorter synonym. We will deal with synonyms in more detail when we get to the section on the vocabulary.

If you now wanted to amend the entry for location 0 it would be displayed at the bottom of the screen as E 1 D 5 W 4 S 3. Type in A 0 on the Movement Menu to have a look; you can then get back to the menu by using CAPS SHIFT 6 or ENTER. If you use ENTER the Editor will copy the input buffer into the database and tell you it has amended the entry even though it hasn't actually changed. Note that you could have typed in the abbreviations initially.

The Movement Table entries we need for our mini adventure are:-

Location 0 E 1 D 5 W 4 S 3
Location 1 S 2 W 0
Location 2 N 1 W 3
Location 3 N 0 E 2
Location 4 E 0
Location 5 U 0

Check these with the map and then amend the Movement Table entries for locations 1 to 5 using the Movement Table menu. You can print the entries to check that they are correct if you wish.

Testing the Adventure

Now that you have entered the location texts and the movements it is time to test the adventure, so select L on the Main Menu. You will be asked whether you require diagnostics and you should reply N & ENTER or just ENTER. Note that the adventure always begins at location 0. You should be able to move to all of our locations using the full words e.g. EAST, or the abbreviations e.g. E. When you are in the bedroom try typing in the following commands:-

To return to the Editor use the word QUIT and if you have found any errors in the location texts or the movements then use the Editor to correct them. If you would like to try out the diagnostics then select L again on the Main Menu and reply Y to the prompt. The diagnostics will not help you much at this stage but you should note that the number in INVERSE in the bottom corner of the screen is the number of the current location. The other 31 numbers (all 0 at the moment) are the values of, what are called, the user flags and they will be explained in a later section.

The Objects

An object is anything that can be manipulated e.g. a key, or moved from place to place or changed from one thing into another e.g. a torch into a lit torch. Most of the objects in our mini adventure are shown on the map in figure 1 but a full list showing the object number, the description needed and the position of the object at the start of the adventure is as follows:-

So, the (unlit) torch starts out at the kitchen, the walking stick starts off being carried and the jewel (which can't be seen because it's in the safe) starts off as not created. Notice that there are two descriptions for the safe and that it is treated as two separate objects. When the safe is opened Object 8 will be destroyed and Object 10 will be created, while the reverse will happen if the safe is closed. Similarly the torch is really two objects which will he swapped over when the torch is switched on or off.

The Object Texts

The descriptions of the objects are entered in exactly the same way as the descriptions of the locations. If you select E on the Main Menu the Object Text menu will he displayed and you will see that it is the same as the Location Text menu except that locno. has been replaced with objno. i.e. object number. If you print the object texts (P) you may not be surprised to find that an Object 0 already exists. Amend the text of Object 0 so that it reads “A lit torch.” and use a different PAPER colour to your permanent PAPER colour. The table in Chapter 16 of the Spectrum manual will explain how to do this. Then insert the texts for objects 1-11 so that all the object texts use the same PAPER colour. After you have printed the texts, checked and corrected them please return to the Main Menu.

The Object Start Locations

Now that the object texts have been inserted into the database we can go about placing the objects where they will be at the start of the adventure. Type in 1 on the Main Menu to select the Object Start Location menu and you will see that the entries can he amended or printed. Entries cannot be inserted because when you insert an object text for an object the Editor automatically inserts an entry of 'not created' for that object in the Object Start Location Table. If you print the Object Start Location entries you should see that our 12 objects (0-11) are all 'not created'. To amend the entry for object 7 so that it starts the adventure at location 3 type in A 7 3 on the Object Start Location menu. 252, 253 & 254 are some special locnos which mean not created, worn & carried respectively so to amend the entry for object 11 so that it starts off being carried type in A 11 254.

Refer back to our list of objects and their start locations and amend all the other entries that need to be changed. You can then print the entries again to check that they are correct. Note that if you type A 0 252 (for instance) the Editor will print 'Amended' even though the entry hasn't changed.

Testing Again

It's time to test the adventure again to check that the objects are where they should be and have the correct descriptions so select L on the Main Menu. When you are in the adventure type in INVENTORY or I to check that you are carrying the walking stick and use the map in figure 1 to check that the other objects are at the correct locations.

If you asked for diagnostics you will see that the second number is now set to 1. The Interpreter which is part of The Quill contains 33, of what are termed, user flags and these will he explained in more detail in a later section. However, as a very brief introduction, these flags are numbered from 0 to 32 and may contain values in the range 0-255. When you ask for diagnostics the values of the first 31 flags (0 to 30) are printed at the bottom of the screen followed, in INVERSE, by the current location number. Flag 1 i.e. the second flag, is used to contain a count of the number of objects carried and as one object is carried in this case, Flag 1 has the value 1.

The Vocabulary

One section of the database contains the vocabulary and this will hold an entry for every word that the computer is to understand. The Vocabulary menu is selected by typing in A on the Main Menu and it allows for words to be inserted and deleted, for the vocabulary to be printed and for the synonyms of a word to be displayed. Synonyms were mentioned earlier when we discovered that the Editor knew that EAST and E meant the same thing. If you print the vocabulary you will see that there are over 30 entries already present and these relate to words which will be needed in most adventures. Each entry consists of up to four letters followed by a number (or word value) and entries with the same word value are synonyms.

The entries in the vocabulary will either hold a whole word e.g. UP, or, if the word has more than four letters, just the first four letters e.g. ASCE(ND). This has the advantage of using up only a little memory and it also reduces the amount of typing the person playing the adventure has to do because he or she will soon learn that only the first four letters of each word are significant. The disadvantage, of course, is that you can't have two words with different meanings which start with the same four letters. This rarely causes problems but note that when you are playing an adventure and want to go NORTHEAST you have to type in NE as the vocabulary says that NORTH is a synonym of N.

Take a look through the vocabulary and you should be able to spot all the words we used when we were doing the Movement Table and in fact the Movement Table can only contain words that are in the vocabulary. Getting back to the Vocabulary menu, type in S ASCEND to see the synonyms of the word ascend (Note that S ASCE is sufficient). Then try inserting the word ORANGE with the value 200 i.e. I ORANGE 200 or I ORAN 200. We haven't an orange in our adventure so delete the entry using D ORAN. Try inserting a word that is already present e.g. I STOP 62 and deleting a word that isn't present e.g. D SPECTRUM. We'll come back to the vocabulary after we've found out what the Interpreter does when a command is typed in.

Decoding the Players command

Each time the player types in a command during an adventure the Interpreter has to decode it. It does this by searching along the command for words which are in it's vocabulary. The word value of the first word recognised is stored in a variable called W1 and similarly the word value of the second word recognised in W2. This means that commands like TURN ON THE TORCH can be reduced to ON TORCH provided the words TURN & THE are not in the vocabulary and that GO TO THE EAST will mean the same as EAST if the words GO, TO & THE are not in the vocabulary. Thus it is important to consider which words are excluded from the vocabulary as well as those which are included.

If no words are recognised the Interpreter gives the reply "I don't understand...". If the Interpreter recognises a word or words, but they neither cause movement (due to no entry in the Movement Table) nor cause an action to be performed (to be explained later) then the Interpreter gives the reply “I can't”, if the value of W1 is greater than 12 or “I can't go in that direction", if the value of W1 is less than 13. Therefore the words in the vocabulary which relate to directions should have word values in the range 1 to 12.

More Movements

The location descriptions in our adventure include statements of the form “The Hall is to the West” and up to now we have moved to the Hall with the commands WEST, W or GO WEST. We are now going to improve the adventure so that it will also obey commands of the form GO TO THE HALL or just HALL. To do this we will need an entry in the vocabulary relating to each location so insert the following entries into the vocabulary.

e.g. to insert the word KITCHEN with a word value of 14 use I KITC 14 on the Vocabulary menu. Print the vocabulary to check the entries are correct and then amend the entries in the Movement Table to include these new words. The Movement Table entries required are:-

Location 0   E 1   D 5    W 4      S 3     KITC 1  CELL 5  BEDR 4  LOUN 3
Location 1   S 2   W 0    DINI 2   HALL 0
Location 2   N 1   W 3    KITC 1   LOUN 3
Location 3   N 0   E 2    HALL 0   DINI 2
Location 4   E 0   HALL 0
Location 5   U 0   HALL 0

When you have changed the Movement Table, test the adventure again to check that commands such as GO TO HALL are obeyed correctly. While testing the adventure note that when you are in the Dining Room, GO NE gives the reply “I can't go in that direction” because NE has a word value less than 13, while GO TO THE HALL gives the reply “I can't” because HALL has a word value greater than 12.

More Words

We will shortly get to the stage where we can begin to manipulate the objects in our adventure. Before we can do that though, the words we will use to manipulate the objects have to be inserted into the vocabulary. Please insert the following entries into the vocabulary:-

The bed is not an object in the adventure and we do not intend to make use of the word BED anywhere else in the database. However, the bed is mentioned in the location description of the bedroom so BED is included in the vocabulary to stop the Interpreter replying "I don't understand..." if a player tries to use the bed.

The Event Table

This table (and the Status Table) form the heart of the database, for it is here that the actions the Interpreter has to take to reply to a player's command are specified. Each entry in the table consists of two word values, a set of conditions and a set of actions. When the adventure is played the Interpreter matches the word values entered by the player (which have been stored in W1 and W2) against each entry in the table. If the word values match and the conditions are satisfied then the actions are performed.

Select G on the Main Menu to display the Event Table menu and you will see that entries can be inserted, amended or printed. Printing is slightly different to the other menus because you may either enter P by itself, P followed by one word or P followed by two words and printing will start at the appropriate part of the table. The words used must of course be present in the vocabulary. If you type in P now you will find that a few entries, which will be needed for most adventures, are already present.

Action INVEN

This is the action which prints “I have with me:-“ etc. The first entry in the Event Table, GET I, has no conditions and a single action called INVEN. What does, this mean? Well if you were playing the adventure and typed in TAKE INVENTORY then, because the word value stored in W1 matched the word value for GET and W2 matched I, action INVEN would be performed. Remember that TAKE & GET and INVENTORY & I are synonyms.

The next entry I _ does the same thing. If the first word recognised by the Interpreter is a synonym of I then action INVEN is performed. The (underline) means that the corresponding value in W1 or W2 (W2 in this case) is irrelevant. Please make sure you fully understand the last two sections on the Event Table before reading further.

Action DESC

The third entry in the Event Table R _, means that if R or REDE(SCRIBE) is entered as a command then action DESC will be performed. Action DESC clears the screen and attempts to describe the current location. ( If it is dark the Interpreter will print "Everything is dark. I can't see." ).

Actions SAVE and LOAD

These are the actions which copy a game position to tape and restore a game position from tape. The last two entries in the Event Table use these actions and mean, for instance, that if LOAD is typed in as a command then action LOAD is performed. Do not be confused by the vocabulary word LOAD and the action word LOAD because they are not related. You can only have an entry in the Event Table of LOAD _ if there is an entry for LOAD in the vocabulary. The action word LOAD is independent of the vocabulary.

Actions QUIT, TURNS and END

Action QUIT is the action which asks “Are you sure you want to quit now?” while action TURNS is the action which prints "You have taken x turn(s).”. Action END is a very important action as it prints “END OF GAME Do you want to try again?" and if you reply "N" it returns you to the Editor. Note that the only way to return to the Editor, after testing an adventure, is by action END being performed.

Actions GET, DROP and OK

Actions GET and DROP must be followed by an objno. and are used to carry or put down objects while action OK simply prints "OK". In our mini adventure we want the player to be able to take and leave the walking stick using the commands TAKE STICK and DROP STICK respectively. The entries needed in the Event Table for this are:-

TAKE STICK 	Conds
			Acts 	GET 	11
					OK
DROP STICK 	Conds
			Acts 	DROP 	11
			OK

To insert the first of these into the Event Table go to the Event Table menu, type in I TAKE STICK and press ENTER. This inserts a null entry for TAKE STICK (i.e. with no conditions and no actions) in the table and displays a cursor at the bottom of the screen to allow you to amend the null entry. When the cursor appears, type in GET 11 OK and press ENTER again. Insert the entry for DROP STICK in the same way and then print the Event Table to check the entries. Notice that the Editor prefers to use the vocabulary word GET instead of TAKE as it is a shorter synonym.

Now test the adventure to see the effect of these entries in the Event Table. In particular try the following commands:-

Condition PRESENT

The entries we need, to be able to GET and DROP the other objects are:-

AS you can see the entries for the torch are not quite so simple. The problem is that the torch is really two objects so we have to have two entries. The condition present which must he followed by an objno., checks whether the object specified is present at the current location. So the first entry for GET TORCH checks whether Object 0 is present and if it is, tries to GET it. If Object 0 is not present the condition is not satisfied so the Interpreter falls through to the next entry, which has no conditions and tries to get Object 1. When an entry has conditions and actions the conditions are typed in, in front of the actions e.g. PRESENT 0 GET 0 OK.

When you have inserted the entries print them to check they are correct and that the entries for the torch are in the correct order. Amending entries in the Event Table is similar to amending entries in the other database tables. However, if there is more than one entry present for the same words e.g. DROP TORCH, then each entry is displayed in turn for amending and you simply press ENTER to leave an entry as it is. Try A DROP TORC on the Event Table menu and keep pressing ENTER until you get back to the menu; both entries should he displayed in turn for possible amending.

Entries in the Event Table can be deleted by removing all the conditions and actions i.e. Amend the entry using CAPS SHIFT 1 to clear the input buffer and then press ENTER. Before we test the adventure again we'll insert a few more entries.

Actions WEAR and REMOVE

These actions enable objects to be worn and removed and must be followed by an objno. Our adventure has two objects that can he worn and the entries needed in the Event Table for this are:-

Words 		Conds 	Acts
-----		-----	----
WEAR HAT 			WEAR 6 OK
REMOVE HAT 			REMOVE 6 OK
WEAR COAT 			WEAR 5 OK
REMOVE COAT 		REMOVE 5 OK

Insert these entries and then test the adventure again using diagnostics. The reason for using diagnostics is to enable you to monitor the value of Flag 1 (the second flag) which has a value equal to the number of objects carried. When you are in the adventure try these commands in the order shown:-

Command 		Response 				Flag 1 value
-------			--------				------------
WEAR HAT 		I don' t have it 			1
REMOVE HAT 		I 'm not wearing it 			1
GET HAT 		OK 					2
TAKE COAT 		OK 					3
KITCHEN 							3
GET TORCH 		OK 					4
DINING 								4
GET APPLE 		I can't carry any more 			4
WEAR HAT 		OK 					3
WEAR HAT 		I'm already wearing it			3
GET APPLE 		OK 					4
REMOVE HAT 		I can't. My hands are full 		4
DROP HAT 		I can't. My hands are full 		4
WEAR COAT 		OK 					3
I 			I have with me				3
DROP HAT 		OK 					3
REMOVE COAT 		OK 					4

Also make sure you can GET the key and drop all the objects you are carrying.

As you can see, the actions GET, DROP, REMOVE and WEAR include quite a bit of checking on the objects being manipulated and they can normally be used without being preceded by conditions. These actions are exceptions to the rule as most other actions will need to be preceded by conditions.

Action SWAP

This action is followed by two objnos and simply swaps over the positions of the two objects e.g. if Object 0 is 'not created' and Object 1 is at location 3 then the action SWAP 0 1 would put Object 0 at location 3 and make Object 1 'not created'. In our adventure we are going to use SWAP to switch the torch on and off. The entries we need are:-

Notice that we have catered for a player giving the command SWITCH OFF TORCH or SWITCH TORCH OFF and that the condition PRESENT 0 means that the torch can only be switched off if the lit torch is present. Insert these entries into the Event table and test them.

The Flags

The Interpreter contains 33 user flags which are really just variables that can hold a value in the range 0 255. Like everything else in The Quill, numbering starts at 0 so the flag numbers (flagnos) are in the range 0-32. There are actions which enable the flag values to be changed and conditions which allow the flag values to be tested. Some of the flags have special purposes while others have an auto-decrement feature. The flags with special purposes are flags 0, 1, 30, 31 and 32. Flag 0 is used to tell the interpreter whether it is light or dark; if it has any value other than zero the Interpreter thinks it's dark. Flag 1 as we have seen before, holds a count of the number of objects carried. Flag 30 is used to hold the players score as a percentage while Flags 31 and 32 are used to hold the number of turns that the player has taken. Flags 2 to 10 are auto-decrement flags which means they are decreased by 1 under certain circumstances:-

Flag 2 is decreased each time the Interpreter tries to describe a location

Flag 3 is decreased each time the Interpreter tries to describe a location and it's dark

Flag 4 is decreased each time the Interpreter tries to describe a location and it's dark and Object 0 is absent

Flags 5-8 are decreased each time a command is entered

Flag 9 is decreased each time a command is entered and it's dark

Flag 10 is decreased each time a command is entered and it's dark and Object 0 is absent

Flags 11-29 have no special features

Note that a flag cannot be decreased below zero and that Object 0 is a special object because the Interpreter considers it as a source of light.

There is a summary of the flags and a summary of the conditions and actions that can be used, on the last page, of this manual. As mentioned earlier, when diagnostics are requested the values of flags 0-30 are printed so that you can monitor the values of these flags.

Light and Dark

If you take another look at our map in figure 1 you will notice that it says the cellar is dark. To make the cellar dark we will use the condition AT and the actions CLEAR, SET, GOTO and DESC. Condition AT must be followed by a locno. and is satisfied if the player is at that location. The actions CLEAR and SET must be followed by a flagno. and change that flags value to 0 or 255 respectively. Action GOTO is followed by a locno. and causes movement to that location.

If this entry were present in the Event Table (do not insert it).

Words 	Cond 	Acts
U _ 	AT 5 	GOTO 0 DESC

it would have exactly the same effect as our entry U 0 for location 5 in the Movement Table i.e. if a player gives the command UP when he is at location 5, he is moved to location 4 and the location is described.

The Event Table entries to be inserted to make the cellar dark are:-

Words 		Conds 		Acts
D _ 		AT 0 		SET 0 GOTO 5 DESC
CELLAR _ 	AT 0 		SET 0 GOTO 5 DESC
U _ 		AT 5 		CLEAR 0 GOTO 0 DESC
HALL _ 		AT 5 		CLEAR 0 GOTO 0 DESC

When a player moves from the Hall to the Cellar, Flag 0 will be set to 255 (making it dark). When he moves back to the Hall, Flag 0 will be cleared to 0 (making it light again). However, if you were to test the adventure now you would find that the Cellar was still light. This is because the Interpreter checks the Movement Table before it checks the Event Table and if the Movement Table causes movement the Event Table is not checked. So remove the movements between the Hall and Cellar from the Movement Table and then test the adventure. When you are testing the adventure monitor the value of flag 0 and try experimenting with moving between the Hall and Cellar and switching the torch on and off.

Action SCORE

The action SCORE prints “You have scored x%" where x is the value of Flag 30. We are going to use a very simple scoring system in our adventure where the player scores 50% for opening the safe and a further 50% for completing the adventure. If the player QUIT's the adventure he will want to know what score he has achieved so amend the Event Table entry for QUIT _ so that it has the actions QUIT SCORE TURNS END. It is important that you print this entry (use P QUIT) to check it is correct, because the only way back to the Editor from the Interpreter is by action END being performed.

Opening and Closing the Safe

In our adventure the safe can only be opened if the key is carried, the lit torch is present and, of course, the safe is not already open. To close the safe, the key is not needed but the lit torch must be present. The first time the safe is opened we want to create the jewel and give the player a score of 50% but if the player closes the safe and reopens it then we must not create the jewel again or give another 50%.

We will use Flag 11 to show whether the safe has already been opened. As the flags start off with a value of zero we will say that if Flag 11 has the value 0 the safe has not previously been opened. Then if we SET Flag 11 the first time the safe is opened we will be able to tell that the safe has already been opened. The Event Table entries we need are:-

OPEN SAFE 	Conds 	PRESENT 	8
			CARRIED 	7
			PRESENT 	0
			ZERO 		11
		Acts 	DESTROY 	8
			CREATE 		10
			LET 		30 50
			CREATE 		9
			SET 		11
			DESC
OPEN SAFE 	Conds	PRESENT 	8
			CARRIED 	7
			PRESENT 	0
		Acts 	DESTROY 	8
			CREATE 		10
			OK
CLOSE SAFE 	Conds 	PRESENT 	10
			PRESENT 	0
		Acts 	DESTROY 	10
			CREATE 		8
			OK

Condition CARRIED must he followed by an objno. and is satisfied if that object is carried while condition ZERO must be followed by a flagno. and is satisfied if that flag has the value 0. Action CREATE is used to change an object's location to the current location while action DESTROY changes at object's location to 'not created'. Both CREATE and DESTROY must be followed by an objno. Action LET is followed by a flagno. & a value, and the flag is given that value e.g. LET 30 50 gives Flag 30 a value of 50; a bit like the BASIC command LET FLAG30 = 50.

The order of the two entries for OPEN SAFE is important. The first time the safe is opened the condition ZERO 11 will be satisfied so the actions in the first entry will be performed. If the safe is opened again the condition ZERO 11 will not be satisfied and the Interpreter will fall through to the second OPEN SAFE entry. Insert these entries into the Event Table, then print them (use P UNLOCK SAFE) to check they are correct. Note that the first OPEN SAFE entry ends with action DESC so that the player can see that the jewel has been created. When you have checked the entries test the adventure again and use diagnostics so that you can monitor the values of flags 11 & 30.

The Message Texts

Any messages which are needed in the adventure have to be entered into the Message Text table. The Message Text menu is the same as the Location Text menu with the exception that locno. has been replaced with mesno. (message number). If you select B on the Main Menu to display the Message Text menu and then print the messages, you will see that a message 0 is already present. The messages we need in our adventure are:-

Message 0 - I'm hungry!
Message 1 - Ah. That's better !
Message 2 - I'm dying of starvation...
Message 3 - Well done. You've solved the Adventure

Amend the existing entry for message 0 and then insert messages 1 to 3.

The Status Table

This table has exactly the same format as the Event Table i.e. each entry has two word values followed by conditions and actions, but the Interpreter uses the two tables in slightly different ways. We have already seen that the Interpreter uses the Event Table after each command given by a player and matches the word values in W1 and W2 with each entry in the table. The Interpreter uses the Status Table in between turns and looks at each entry irrespective of the word values in W1 and W2. Thus the Event Table contains entries which are dependent on the commands entered by the player while the Status Table contains entries which are independent of the commands entered by the player. Note that the Interpreter does not make use of the word values present in the Status Table entries. The vocabulary words used in the Status Table can therefore be used as comments, to remind you what the entries do, or to position an entry at a particular place in the table because the entries are arranged in ascending order of word value. When you write your own adventures you will find that the order of the entries in the Status Table is very important.

Finishing the Adventure

Our mini adventure is solved when a player is at the Dining Room and the jewel is present. It doesn't matter what commands the player uses to get the jewel to the DINING ROOM so we will use an entry in the Status Table to detect when the adventure is solved. The Status Table entry required is:-

FINISH __	Conds		AT	2
				PRESENT 9
		Acts 		MESSAGE 3
				PLUS 	30 50
				BEEP 	20 140
				BEEP 	20 160
				BEEP 	20 180
				BEEP 	90 200
				SCORE
				TURNS
				END

Note that the vocabulary word FINISH is used only as a comment.

Select H on the Main Menu to display the Status Table menu and then insert this entry. Action MESSAGE must be followed by a mesno. and simply prints that message. Action PLUS must be followed by a flagno. & a value, and adds that value to the appropriate flag e.g. PLUS 30 50 adds 50 to Flag 30 (the score). Action BEEP is followed by a duration and a pitch; the duration is in hundredths of a second and, like pitch, is in the range of 0-254. Action BEEP can be considered to execute the BASIC command BEEP duration/100, Pitch/2 -60. Thus the action BEEP 20 140 is equivalent to the BASIC command BEEP .2,10.

When you have inserted this entry in the Status Table test the adventure again arid take the jewel to the Dining Room.

Hunger

In our adventure we want the player to become hungry after 6 turns, to remain hungry for the next 7 turns and then to die of starvation. Eating the apple, of course, will ward off the pangs of hunger. We will set Flag 12 when the apple is eaten and we will use Flag 5, which is auto-decremented each turn, to count the 7 turns when the player is hungry. The entries needed in the Status Table are:-

HUNGER __	Conds	EQ	31 6
			ZERO 	32
		Acts 	LET 	5 8
HUNGER __ 	Conds 	NOTZERO 5
			ZERO 	12
		Acts 	MESSAGE 0
HUNGER __ 	Conds 	EQ 	5 1
			ZERO 	12
		Acts 	MESSAGE 2
			PAUSE 	100
			BEEP 	20 200
			BEEP 	20 180
			BEEP 	20 160
			BEEP 	90 140
			SCORE
			TURNS
			END

Note that the vocabulary word HUNGER is only used as a comment.

The condition EQ must be followed by a flagno. & a value, and is satisfied if the flag specified has the value specified. Condition NOTZERO must also be followed by a flagno. and is satisfied if the flag specified does not have the value 0. The action PAUSE is similar to the BASIC command of the same name. Insert these three entries into the Status Table but make sure you insert them in the order shown. The first entry waits until the turns count (Flags 31 and 32) is equal to 6 and it then gives Flag 5 a value of 8. The second entry is the one which prints "I'm hungry!" and it does this when Flag 5 is not zero and Flag 12 says the apple has not been eaten. Flag 5 is auto-decremented each turn. The conditions in the third entry are satisfied when Flag 5 reaches 1 and Flag 12 says the apple has not been eaten. Note that when Flag 5 has the value 1 the conditions in both the second and third entries are satisfied so both the messages "I'm hungry!" and “I'm dying of starvation...” are printed.

Eating the Apple

We have already said that we will set Flag 12 when the apple is eaten. However, we only want to print message 1 if the apple is eaten when the player is hungry i.e. if the apple is eaten before the player is hungry we just want the reply “OK”. The entries required in the Event Table are:-

EAT APPLE 	Conds 	PRESENT 	2
			NOTZERO 	5
		Acts 	DESTROY 	2
			SET 		12
			MESSAGE 	1
			DONE
EAT APPLE 	Conds 	PRESENT 	2
		Acts 	DESTROY 	2
			SET 		12
			OK

Action DONE simply stops the Interpreter falling through to the next entry in the table. Insert these two entries into the Event (Not Status) table in the correct order.

Number of Objects Conveyable

You may remember when you were testing the adventure earlier, that the player was able to carry only 4 objects. This number can be altered by selecting P on the Main Menu. For our mini adventure change the number of objects conveyable to 1 (one) and then test the adventure for the last time (it won't be quite so easy this time).

Save and Verify Adventure

These two Options on the Main Menu allow complete copies of an adventure to be saved to tape in a form that will auto-run when loaded into a Spectrum using LOAD"". Note that the files saved are not designed to be reloaded into The Quill.

Deleting Words from the Vocabulary

Note that if all the synonyms of a word are deleted from the vocabulary then:-

a) Any entries in the Event and Status Tables using those words are also deleted.
b) Any movements in the Movement table using those words are also deleted.

Other Actions

All but two of the actions available in The Quill were used in our mini adventure. The other two are MINUS and ANYKEY. MINUS is followed by a flagno. and a value, and subtracts the value specified from the flag specified. Action ANYKEY prints “Press any key to continue” and waits for a key to be pressed. One use of ANYKEY is to provide an introduction to adventures. If the introduction occupies two screens, then insert it into the database as the texts for locations 0 & 1 and let the adventure proper start at location 2. The following entries in the Status table can then be used to do the introduction:-

INTRO 	- 	Conds 	AT 	0
		Acts 	ANYKEY
			GOTO 	1
			DESC
INTRO 	- 	Conds 	AT 	1
		Acts 	ANYKEY
			GOTO 	2
			DESC

More about Event and Status

When the interpreter is processing these tables it considers each entry till it reaches the end of the table or it performs one of the actions lNVEN, DESC, END, DONE, OK, SAVE or LOAD. The actions QUIT, REMOVE, GET, DROP, and WEAR can sometimes also stop processing of the Event/Status tables. Full details of all the actions can be found in Part 2 of this manual.

Other Conditions

Our mini adventure made use of only 6 of the 16 conditions available in The Quill. Details of the other conditions can be found in Part 2 of this manual but it is worth mentioning the condition CHANCE here as it can introduce a random element into an adventure. Condition CHANCE must be followed by a percentage, in the range 0-99, e.g. CHANCE 25 would have a 25% chance of being satisfied.

Designing your own Adventure

The suggested procedure of writing your own adventure is:-

a) Read Part 2 of this manual
b) Draw a map of your adventure and allocate locnos.
(make your first adventure a small adventure)
c) List the location texts you will use
d) List the Movement table entries you will need
e) List the objects in the adventure showing where they will start the adventure. Allocate objnos
f) List the messages needed in the adventure and allocate mesnos
g) List all the words and synonyms you will use and allocate word values
h) Decide which flags will be used and what they will be used for
i) Write out all the Event table entries showing the conditions and actions to be used. If you have more than one entry with the same word values check that you have the entries in the correct order
j) Write out all the Status table entries and plan the order of the entries. You might need to add further entries to the vocabulary which will be used as comments in the Status table
k) Insert the entries into the database and save the database regularly (you might get a power cut)
l) Thoroughly test your adventure

As you can see you need to do a lot of planning before you start to type your adventure into The Quill.

If you intend to sell adventures then they need to be very thoroughly tested by as many people as possible. In particular:

a) Check the spelling of every word
b) Check it is impossible to get a score of over 100%
c) Try to move in every direction from every location
d) Try to GET, DROP, WEAR and REMOVE each object
e) It should be possible to solve the adventure each time it is played provided the correct commands are used e.g. poison gas which has a 1% chance of appearing and killing the player should be avoided unless you also provide a gas mask.

Part 2

Detailed Description of the Interpreter

The structure of the Interpreter is shown in flowchart 1. The numbers shown on the flowchart relate to the following paragraphs:-

1 Initialise
All the flags are set to zero except for Flag 1 which is set to the number of objects initially carried. The current location and the two word values W1 & W2 are set to zero.

2 Describe Current Location
The screen is cleared. If Flag 2 is non zero it is decremented. If it is dark (Flag 0 is non zero) and Flag 3 is non zero it is decremented. If it is dark and Flag 4 is non zero it is decremented if Object 0 is absent.

If it is light (Flag 0 is zero) or Object 0 is present the location text for the current location is printed. Then, if any objects are at this location, SM1 "I can also see:-" is printed followed by the object texts. SM1 refers to Sytem Message number 1.

If it is dark (Flag 0 is non zero) and Object 0 is absent "Everything is dark. I can't see." is printed.

3 Consider 1st Entry in Status Table.
A pointer is set to the first entry in the Status table.

4 Words & Conditions Satisfied The 1st word & 2nd word in the entry being considered are matched with W1 & W2 as shown in flowchart 2. Each condition in the entry is checked as follows:-

4.1 AT locno.
Satisfied if the current location is the same as locno.

4.2 NOTAT locno.
Satisfied if the current location is different to locno.

4.3 ATGT locno.
Satisfied if the current location is greater than locno.

4.4 ATLT locno.
Satisfied if the current location is less than locno.

4.5 PRESENT objno.
Satisfied if Object objno. is carried or worn or at the current location.

4.6 ABSENT objno.
Satisfied if Object objno. is not carried and not worn and not at the current location.

4.7 WORN objno.
Satisfied if Object objno. is worn.

4.8 NOTWORN objno.
Satisfied if Object objno. is not worn.

4.9 CARRIED objno.
Satisfied if Object objno. is carried.

4.10 NOTCARR objno.
Satisfied if Object objno. is not carried.

4.11 CHANCE percent.
Satisfied if percent is less than or equal to a random number in the range 1-100 (inclusive).

4.12 ZERO flagno.
Satisfied if Flag flagno. is set to zero.

4.13 NOTZERO flagno.
Satisfied if Flag flagno. is not set to zero.

4.14 EQ flagno. value
Satisfied if Flag flagno. is set to value.

4.15 GT flagno. value
Satisfied if Flag flagno. is set to greater than value.

4.16 LT flagno. value
Satisfied if Flag flagno. is set to less than value.

Structure of Interpreter

Words & Conditions Satisfied

5 Consider 1st Action
A pointer is set to the first action in the entry being considered.

6 Perform Action
The action is performed as follows:-

6.1 INVEN
“I have with me:-" is printed. If no objects are carried or worn "Nothing at all." is printed, otherwise the object text for each object that is carried or worn is printed. If an object is worn its object text is followed by "(worn)".

Action DONE is then performed.

6.2 DESC
This action jumps out of STATUS/EVENT processing to Describe Current Location.

6.3 QUIT
"Do you really want to quit now?" is printed and the input routine called. If the reply does not start with "Y" action DONE is performed.

6.4 END
“END or GAME Do you want to try again?” is printed and the input routine called. If the reply does not start with N a jump is made to Initialise. Otherwise a jump is made to the Editor (if it is present) or to the BASIC NEW command.

6.5 DONE
This action jumps to the end of STATUS/EVENT processing i.e. no more actions or entries are considered.

6.6 OK
"OK" is printed and action DONE is performed.

6.7 ANYKEY
"Press any key to continue" is printed at the bottom of the screen and the keyboard is scanned until a key is pressed.

6.8 SAVE
"Start tape, then press any key." is printed at the bottom of the screen. When a key is pressed the game position is saved to tape, then action DESC is performed. If BREAK is pressed during the save a jump is made to Initialise.

6.9 LOAD
Loads data (which should be a game position) from tape, then action DESC is performed. If BREAK is pressed during the load or a tape error is detected a jump is made to Initialise. If data is loaded which is not a game position a tape error will normally be detected.

6.10 TURNS
You have taken x turn(s). is printed where x is Flag 31 + 256 * Flag 32.

6.11 SCORE
You have scored x% is printed where x is Flag 30.

6.12 PAUSE value
Pauses for value/50 secs. However, if value is zero then the pause is for 256/50 secs.

6.13 GOTO locno.
Changes the current location to locno.

6.14 MESSAGE mesno.
Message mesno. is printed.

6.15 REMOVE objno.
If Object objno. is not worn, “I'm not wearing it.” is printed and action DONE is performed.

If the maximum number of objects is being carried (Flag 1), "I can' t. My hands are full.” is printed and action DONE is performed.

Otherwise the position of Object objno. is changed to 'carried' and Flag 1 is decremented.

6.16 GET objno.
If Object objno. is worn or carried, “I already have it.” is printed and action DONE is performed.

If Object objno. is not at the current location, "It's not here.” is printed and action DONE is performed.

If the maximum number of objects is being carried (Flag 1), “I can't carry any more.” is printed and action DONE is performed.

Otherwise the position of Object objno. is changed to 'carried' and Flag 1 is incremented.

6.17 DROP objno.
If objno. is worn and the maximum number of objects is being carried (Flag 1), “I can't. My hands are full.” is printed and action DONE is performed.

If Object objno. is neither worn nor carried, “I don't have it.” is printed and action DONE is performed.

Otherwise the position of Object objno. is changed to the current location and Flag 1 is decremented if the object was carried.

6.18 WEAR objno.
If Object objno. is worn, “I'm already wearing it.” is printed and action DONE is performed.

If Object objno. is not carried, “I don't have it.” is printed and action DONE is performed.

Otherwise the position of Object objno, is changed to 'worn' and Flag 1 is decremented.

6.19 DESTROY objno.
The position of Object objno. is changed to 'not created' and Flag 1 is decremented if the object was carried.

6.20 CREATE objno.
The position of Object objno. is changed to the current location and Flag 1 is decremented if the object was carried.

6.21 SWAP objno. objno.
The positions of the two objects are exchanged.

6.22 SET flagno.
Flag flagno. is set to 255.

6.23 CLEAR flagno.
Flag flagno. is cleared to 0.

6.24 PLUS flagno. value
Flag flagno. is increased by value. If the result exceeds 255 the flag is set to 255.

6.25 MINUS flagno. value
Flag flagno. is decreased by value. If the result is negative the flag is set to 0.

6.26 LET flagno. value
Flag flagno. is set to value.

6.27 BEEP duration pitch
Executes the BASIC command BEEP duration/100, pitch/2 - 60.

7 Consider Next Action
A pointer is set to the next action in the entry being considered.

8 Consider Next Entry
A pointer is set to the next entry in the table being processed.

9 Get Command
If Flags 5 to 8 are non zero they are decremented. If it is dark (Flag 0 is non zero) and Flag 9 is non zero it is decremented. If it is dark and Flag 10 is non zero it is decremented if Object 0 is absent.

The turns count (Flags 31 & 32) is incremented, one of four messages e.g. “Tell me what to do.” is printed and the input routine called. The first four letters of each word in the reply are looked up in the vocabulary and the values of the first two words found in the vocabulary are stored in W1 & W2.

10 Lookup W1 in Movement Table
The entry in the movement table for the current location is searched to see if the word value in W1 is present. If it is, the current location is set to the value following W1 in the movement table.

11 Consider 1st Entry in Event Table
A pointer is set to the first entry in the Event table.

The basic structure of the interpreter has its origins in an article written by Ken Reed and published in the August 1980 issue of Practical Computing. The interpreter in The Quill now has little in common with the article but the terms used to describe it (e.g. Status, Event, Flags) have been retained as an aid to people who are familiar with the article.

Detailed Description of the Database

The database consists of a number of inter-related tables and also contains an area of miscellaneous information e.g. values of permanent colours, number of objects conveyable. The tables present are:-

A The Vocabulary
Each entry in the table uses 5 bytes and contains a word (or the first four characters, if the word is longer than four characters) and a word value in the range 1-254. Words with the same word value are called synonyms. The entries are held in ascending order of word value and within each word value, entries with more spaces come first e.g.

U
UP
CLIM
ASCE

where entries with the same word value also have the same number of spaces the entry inserted first comes earlier e.g. CLIM(B) was inserted before ASCE(ND).

Note 1. Whenever the editor has to convert from a word value to a word it takes the first word with that value.

Note 2. Word values less than 13 should be reserved for movement words.

B The Message Text table
This table contains the text of any messages which are needed for the adventure. The messages are numbered from 0 upwards and each one uses 3 bytes plus the length of the text.

C The Location Text table
This table, which has an entry for each location, contains the text which is printed when a location is described. Each entry uses 3 bytes plus the length of the text. The entries are numbered from 0 upwards and location 0 is the location at which the adventure starts. Whenever a new location is inserted a null entry for that location is also made in the movement table.

D The Movement Table
This table has an entry for each location and each entry may either be empty (null) or contain a number of 'movement pairs'. A movement pair consists of a word value in the vocabulary followed by a location number and means that any word with that word value causes movement to that location. A typical entry could be SOUTH 6 EAST 7 ENTER 6 NORTH 5 which means that SOUTH or ENTER or their synonyms cause movement to location 6, EAST or it's synonyms to location 7 and NORTH or it's synonyms to location 5. Each entry uses 3 bytes plus 2 bytes for each movement pair.

Note 1. The movement pairs contain the word value not the actual word and if a word value is deleted from the vocabulary then all movement pairs which contain that word value are also deleted.

Note 2. When the adventure is being played it is only the first recognised word (W1) which will cause movement.

Note 3. If any movements are to be performed in the Event or Status tables using the action GOTO then those movements should be excluded from the Movement table.

E The Object Text table
This table, which has an entry for each object, contains the text which is printed when an object is described. Each entry uses 3 bytes plus the length of the text. An object is anything in the adventure which may he manipulated and objects are numbered from 0 upwards. Object 0 is assumed by the Interpreter to be a source of light. Whenever a new object text is inserted an entry of 'not created' is made for that object in the object start location table.

F The Object Start Location table
This table has a 1 byte entry for each object, which specifies the location at which the object is situated at the beginning of the adventure. An object can also start the adventure being worn, carried or not created.

G. The Event table
This table (together with the Status table) is the main part of the database and each entry contains 2 word values followed by any number of conditions and then (normally) at least one action. When the adventure is played, if there is an entry in the table with the word values entered and the conditions specified are satisfied then the actions are performed. The conditions and actions that may be present and the effect that they have is fully specified in the description of the interpreter. The order of entries in the table is in ascending order of the first word value. Entries which have the same first word value are held in ascending order of the second word value. Entries with the same first and second word values are held in the order they were inserted into the database (i.e. they must be inserted in the order required). An example of the order of the table, with word values shown in brackets, is as follows:-

Each entry in the table has an overhead of 6 bytes and each condition and action uses 1, 2 or 3 bytes depending on the number of parameters.

Note 1. If a word value is deleted from the vocabulary then all entries in the Event and Status tables which contain that word value are also deleted.

H The Status table
This table has exactly the same format as the Event table. When the adventure is played the Status table is scanned between turns to see if the Spectrum wants anything to happen. The Event table can he considered as the player’s table and contains entries which are dependent on the words entered, while the Status table is the computer's table and contains entries which are independent of the words entered by the player. The words in the Status table can however be used to position entries at the required place and/or as a reminder of the purpose of the entries.

I The UDG's
This table, which is 168 bytes long, contains the User Defined Graphics The UDG's cannot be changed with the Editor but the address at which they start is given when The Quill is loaded. The UDG's can be changed by using BASIC to set up the required values at the correct address and then saving them to tape. The file of UDG's can subsequently be loaded into the database using the Load Database command .

J The Interpreter Messages
This table contains the system messages used by the Interpreter e.g. "I'm not wearing it.”. These messages cannot be changed with the Editor. A file is supplied with The Quill which, if loaded using the Load Database command, will change the messages so that "You” is used instead of “I”, e.g. “You're not wearing it.”. Some people may prefer this format for particular adventures.

Files to convert the Interpreter to other languages will be produced if there is a demand for them.

Detailed Description of the Editor

A Vocabulary
Words may be, inserted or deleted, synonyms of a word may be displayed or the vocabulary may be printed:-

Insert I word No. (No. is in the range 1-254)

If word is not already present in the vocabulary it is inserted with a word value of No.

Delete D word

If word is present in the vocabulary, it and it's word value are deleted. If synonyms of the word deleted are present in the vocabulary no further action is taken. However, if no synonyms are present, then:-

a) all entries in the Event and Status tables which use this word value are also deleted.
b) all movements in the movement table which use this word value are also deleted.

Show Synonyms S word

If word is present in the vocabulary, it and all other words with the same word value are, displayed.

Print P or L

Printing is either to the screen using P or to the printer using L.

Points to note:
a) Be careful using delete as it can also affect the Event, Status and Movement tables.
b) Words with a word value of less than 13 are assumed to be movement words by the Interpreter and cause the message “I can't go in that direction," to be printed instead of “I can't”.

B Message Text
Message texts may be inserted, amended or printed:-

Insert I

The next available message number is used and a null entry is made for it in the message text table. An automatic call to the amend routine is then made to allow the user to amend the null entry.

Amend A mesno.

The existing text for message mesno. is copied to the input buffer and displayed at the bottom of the screen for amending. When ENTER is pressed the existing text is replaced with the contents of the input buffer.

Print P (mesno.) or L (mesno.)

Printing is either to the screen using P or to the printer using L. Printing starts with the text for message mesno. or at the beginning if mesno. is not specified.

Points to note:
a) There is a limit of 255 messages.

C Location Text

Location texts may be inserted, amended or printed:-

Insert I

The next available location number is used and a null entry is made for it in both the movement table and the location text table. Processing then continues with an automatic call to the amend routine to allow the user to amend the null entry already set up in the location text table.

Amend A locno.

The existing text for location locno. is copied to the input buffer and displayed at the bottom of the screen for amending. When ENTER is pressed the existing entry is replaced with the contents of the input buffer.

Print P (locno.) or L (locno.)

Printing is either to the screen using P or to the printer using L. Printing starts with the text for Location locno. or at the beginning if locno. is not specified.

Points to note:
a) The start of an adventure is always at Location 0.
b) There is a limit of 252 locations.

D Movement table Movements may be amended or printed:-

Amend A locno.

The existing entry for Location locno. is decoded, copied to the input buffer and displayed at the bottom of the screen for amending. When ENTER is pressed the input buffer is vetted to be empty or to contain word locno. repeated any number of times. word must be present in the vocabulary and locno. must be present in the location text table. If there are no syntax errors the existing entry is replaced with an encoded copy of the input buffer (i.e. words changed to word values).

Print P (locno.) or L (locno.)

Printing is either to the screen using P or to the printer using L. Printing starts with the entry for Location locno. or at the beginnings if locno. is not specified.

Points to note:
a) A location text must be present for a Location before movements can be present.
b) Any words in the Vocabulary may be used in the Movement table.
c) When an entry is decoded (for Amend or Print) the word value is changed into the first word in the Vocabulary with that word value.

E Object Text
Object texts may be inserted, amended or printed:-

Insert I

The next available object number is used and a null entry is made for it in the object text table. An entry of 'not created' is also made for it in the object start location table. Processing then continues with an automatic call to the amend routine to allow the user to amend the null entry already set up in the object text table.

Amend A objno.

The existing text for Object objno. is copied to the input buffer and displayed at the bottom of the screen for amending. When ENTER is pressed the existing text is replaced with the contents of the input buffer.

Print P (objno.) or L (objno.)

Printing is either to the screen using P or to the printer using L. Printing starts with the text for Object objno. or at the beginning if objno. is not specified.

Points to note:
a) Object 0 is considered by the Interpreter to be a source of light.
b) There is a limit of about 210 objects.

F Object Start Location Table

The location at which an object is situated at the start of the adventure may be amended or the object start location table may be printed:-

Amend A objno. locno.

The existing entry for Object objno. is replaced with locno. which must either be present in the location text table or be one of the special locnos. 252 not created, 253 worn or 254 carried.

Print P or L

Printing is either to the screen using P or to the printer using L

Points to note:
a) An object text must be present for an object before it's start location can be present.

G Event Table

Entries may be Inserted, Amended, Deleted or Printed:-

Insert I word1 word2

Word1 and Word2 must be underline characters or words which are in the vocabulary. The word values of Word1 and Word2 (underline has a word value of 255) are used to find the correct place in the table for the new entry to be created. If any entries already exist for Word1 Word2 then the new entry will be created after the existing entries. A null entry is created at the appropriate place and an automatic call made to the amend routine to allow the user to amend the null entry.

Amend A Word1 Word2

The first entry in the table with word values of Word1 and Word2 is copied to the input buffer and displayed at the bottom of the screen for amending. When ENTER is pressed the input buffer is vetted to be empty, in which case the existing entry is deleted, or to contain any number of valid conditions followed by at least one valid action. If there are no syntax errors the existing entry is replaced with the contents of the input buffer. Any following entries in the table with the same word values (i.e. Word1 and Word2) are then displayed in turn for amending in the same way.

The conditions that may be used are:-

AT         locno.
NOTAT      locno.
ALGT       locno.
ATLT       locno.
PRESENT    objno.
ABSENT     objno.
WORN       objno..
NOTWORN    objno.
CARRIED    objno..
NOTCARR    objno.
CHANCE     percent (percent, is in the range 0-99)
ZERO       flagno.
NOTZERO    flagno.
EQ         flagno. value
GT         flagno. value (value is in the range 0-254)
LT         flagno. value

The description of the interpreter will tell you what these conditions do. The actions that may be used are:-

INVEN
DESC
QUIT
END
DONE
OK
ANYKEY
SAVE
LOAD
TURNS
SCORE
PAUSE      value (value is 1/50 sec in the range 0-254)
GOTO       locno.
MESSAGE    mesno.
REMOVE     objno.
GET        objno.
DROP       objno.
WEAR       objno.
DESTROY    objno.
CREATE     objno.
SWAP       objno. objno.
SET        flagno.
CLEAR      flagno.
PLUS       flagno. value
MINUS      flagno. value  (value is in the range 0-254)
LET        flagno. value
BEEP       duration pitch (duration and pitch are in the range 0-254. 
                           Duration is in 1/100 sec. The value of pitch 
                           is obtained by taking the value you would use 
                           in a BASIC BEEP command, adding 60 then 
                           multiplying by 2.)

The description of the Interpreter will tell you in detail what these actions do. However, please note that the actions marked ? will always cause an exit from the Event/Status table entry being processed so any following actions will 11 never be performed. The actions marked ? may cause an exit from the table being processed.

Delete

To delete an entry amend it so that no conditions or actions remain.

Print P (word1 (word2)) or L (word1 (word2))

Printing is either to the screen using P or to the printer using L. Printing starts at the first entry with word values of Word1 Word2. If Word1 or Word2 is not specified then a word value of 0 is assumed. Thus P or L by itself starts at the beginning of the table.

H Status Table
The Status table is handled in exactly the same way as the Event Table.

I Save Database
Equivalent to the BASIC command SAVE f Code m,n where m is the start address of the database and n is the length.

J Verify Database
Equivalent to the BASIC command VERIFY f CODE m,n

K Load Database

Equivalent to the BASIC command LOAD f CODE i.e. it will load any file of bytes back to the address it was saved from. As well as loading a database this can be used to load a file of UDG's provided they have been saved from the correct address and with a length not greater than 168. This command can also be used to load the file called “You” supplied with The Quill, which will change the Interpreter messages so that they use "You" instead of "I".

Very Important

If BREAK is pressed or a tape error is detected during a load then the database held in memory will be corrupt and should not be used as it may corrupt the Editor and Interpreter. Under these circumstances the only Editor command which may he used safely is Load Database and this should be used until a database is loaded successfully.

L Test Adventure
"Do you require diagnostics?” is printed and any reply that doesn't start with "Y" is assumed to be negative. A jump is then made to the Interpreter. If diagnostics are required then whenever the Interpreter's input routine is used the bottom four lines of the screen will display the values of flags 0-30 and the value of the current location. The first of the four lines will contain the values of flags 0-7, the second line flags 8-15 the third line flags 16-23 and the fourth line flags 24-30 followed by the value of the current location in inverse. Note that the use of diagnostics will cause the screen to scroll earlier than usual.

Very Important

The only way back to the Editor from the Interpreter is by performing the action END in either the EVENT or STATUS tables.

M Save Adventure
The Interpreter and database arc saved to tape with the file name specified and in such a way that the Adventure will auto run when loaded I rom BASIC using LOAD""."".

N Verify Adventure
Verifies that an Adventure has been saved correctly

O Bytes Spare
The address of the first spare byte and the number of spare bytes are printed. If the address of the first spare byte is less than 32769 then the Adventure will fit into a 16k machine.

P Objects Conveyable
The number of objects that can be carried at any one time may be set to any value from 0 to 254. A value less than 10 will normally be used.

Q Permanent Colours
The BORDER, PAPER & INK colours may be set to any valid values. INK 9 (i.e. contrast) is recommended but please note that INK 9 behaves differently in the bottom part of the screen.

(c) Return to BASIC
Jumps to that BASIC NEW command.

Editor Error Messages and their meanings

BREAK
BREAK was pressed during a peripheral operation

STOP in INPUT
CAPS SHIFT 6 pressed

Tape loading error
as BASIC. Note that a tape error during a LOAD means that the database is corrupt

Database full
Insufficient room in the database for what you were attempting

Limit reached
The maximum number of locations, messages or objects is already present

Out of Memory
Entry for Event Status or Movement table is too large for input buffer (very unlikely to occur). The remedy is to use a smaller entry

Note 1
During input the Spectrum will give out a RASP if the screen and/or input buffer is full.

Note 2
If an entry is present in the Database which is too big to fit on one screen, the Spectrum will give out a RASP when the entry is displayed at the bottom of the screen for amending.

Note 3
If an abnormally large entry is inserted in the movement table using abbreviations e.g. N I W 6 S 4 etc and the abbreviations are deleted from the vocabulary, the movement entry (when decoded) i.e. NORT I WEST 6 SOUT 4 etc could be too big for the input buffer. If this happens an out of Memory message will be produced. The remedy is to reinsert the abbreviations in the vocabulary.

Summary of Conditions, Actions and Flags

Conditions 			Actions

AT locno. 			INVEN
NOTAT locno. 		DESC
ATGT locno. 		QUIT
ATLT locno. 		END
PRESENT objno. 		DONE
ABSENT objno. 		OK
WORN objno. 		ANYKEY
NOTWORN objno. 		SAVE
NOTCARR objno. 		TURNS
CHANCE percent 		SCORE
ZERO flagno. 		PAUSE value
NOTZERO flagno. 	GOTO locno.
EQ flagno. value 	MESSAGE mesno.
GT flagno. value 	REMOVE objno.
LT flagno. value 	GET objno.
CARRIED objno. 		WEAR objno.
			DROP objno.
			DESTROY objno.
			CREATE objno.
			SWAP objno. objno.
			SET flagno.
			CLEAR flagno.
			PLUS flagno. value
			MINUS flagno. value
			LET flagno. value
			BEEP duration pitch

Flags

Flag 0 		If this f lag is set to zero it is light. Any other value means it's dark
Flag 1 		holds count of objects carried
Flag 2 		decreased when a location is described
Flag 3 		decreased when a location is described and it's dark
Flag 4 		decreased when a location is described and it's dark and object 0 is absent
Flags 5-8 	decreased each turn
Flag 9 		decreased each turn when it's dark
Flag 10 	decreased each turn when it's dark and Object 0 is absent
Flags 11-29 ordinary flags
Flag 30 	holds the score
Flag 31 	holds turns count LSB
Flag 32 	holds turns count MSB

- ends -