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AGIWiki/Logic syntax (view source)

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{{AGIWiki}}
{{AGIWiki}}


This article describes the '''logic syntax''' for the C-like "official" AGI syntax described in the [[AGIWiki/AGI Specs|AGI Specs]] and supported by [[AGIWiki/AGI Studio|AGI Studio]] and [[AGIWiki/WinAGI|WinAGI]].
This article describes the '''logic source''' for the C-like "official" AGI source described in the [[AGIWiki/AGI Specs|AGI Specs]] and supported by [[AGIWiki/AGI Studio|AGI Studio]] and [[AGIWiki/WinAGI|WinAGI]].


'''Note:''' The [[AGIWiki/WinAGI|WinAGI]] development environment supports an [[AGIWiki/VB Logic Syntax|alternate syntax]], that is based on Microsoft's Visual Basic language, rather than the C language. At this time, the C-based syntax described in this article is the most widely-supported AGI logic syntax.
'''Note:''' The [[AGIWiki/WinAGI|WinAGI]] development environment supports an [[AGIWiki/VB Logic source|alternate source]], that is based on Microsoft's Visual Basic language, rather than the C language. At this time, the C-based source described in this article is the most widely-supported AGI logic source.


== Action Commands ==
== Action Commands ==
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Normal action commands are specified by the command name followed by parentheses which contain the arguments, separated by commas. A semicolon is placed after the parentheses. The parentheses are required even if there are no arguments. The arguments given must have the correct prefix for that type of argument as explained later in this document (this is to make sure the programmer does not use a [[AGIWiki/Variable|variable]], for example, when they think they are using a [[AGIWiki/Flag|flag]]).
Normal action commands are specified by the command name followed by parentheses which contain the arguments, separated by commas. A semicolon is placed after the parentheses. The parentheses are required even if there are no arguments. The arguments given must have the correct prefix for that type of argument as explained later in this document (this is to make sure the programmer does not use a [[AGIWiki/Variable|variable]], for example, when they think they are using a [[AGIWiki/Flag|flag]]).


<syntax type="C++">
<source lang="cpp">
assign.v(v50,0);
assign.v(v50,0);


program.control();
program.control();
</syntax>
</source>


Multiple commands may be placed on the one line:  
Multiple commands may be placed on the one line:


<syntax type="C++">
<source lang="cpp">
reset(f6); reset(f7);
reset(f6); reset(f7);
</syntax>
</source>


Substitutions for the following action commands are available:
Substitutions for the following action commands are available:


<syntax type="C++">
<source lang="cpp">
increment(v30);      v30++;
increment(v30);      v30++;
decrement(v30);      v30--;
decrement(v30);      v30--;
Line 40: Line 40:
lindirectv(v30,v32); *v30 = v32;
lindirectv(v30,v32); *v30 = v32;
rindirect(v30,v32);  v30 = *v32;
rindirect(v30,v32);  v30 = *v32;
</syntax>
</source>


== If structures and test commands ==
== If structures and test commands ==
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An if structure looks like this:
An if structure looks like this:


<syntax type="C++">
<source lang="cpp">
if (test commands) {
if (test commands) {
   action commands
   action commands
}
}
</syntax>
</source>


or like this
or like this


<syntax type="C++">
<source lang="cpp">
if (test commands) {
if (test commands) {
   action commands
   action commands
Line 61: Line 61:
   more action commands
   more action commands
}
}
</syntax>
</source>


Carriage returns are not necessary:
Carriage returns are not necessary:


<syntax type="C++">
<source lang="cpp">
if (test commands) { action Commands } else { more action commands }
if (test commands) { action Commands } else { more action commands }
</syntax>
</source>




Test commands are coded like action commands except there is no semicolon. They are separated by <code>&&</code> or <code>||</code> for AND and OR, respectively:
Test commands are coded like action commands except there is no semicolon. They are separated by <code>&&</code> or <code>||</code> for AND and OR, respectively:


<syntax type="C++">
<source lang="cpp">
if (isset(f5) &&
if (isset(f5) &&
     greatern(v5,6)) { ......
     greatern(v5,6)) { ......
</syntax>
</source>


Again, carriage returns are not necessary within the if statement:
Again, carriage returns are not necessary within the if statement:


<syntax type="C++">
<source lang="cpp">
if (lessn(v5,6) && (greatern(v5,2)) { .......
if (lessn(v5,6) && (greatern(v5,2)) { .......


if (isset(f90) && equalv(v32,v34) &&
if (isset(f90) && equalv(v32,v34) &&
     greatern(v34,20)) { .......
     greatern(v34,20)) { .......
</syntax>
</source>


A&nbsp;! placed in front of a command signifies a NOT.
A&nbsp;! placed in front of a command signifies a NOT.


<syntax type="C++">
<source lang="cpp">
if (!isset(f7)) {
if (!isset(f7)) {
   ......
   ......
</syntax>
</source>


Boolean expressions are not necessarily simplified so they must follow the rules set down by the file format. If test commands are to be ORred together, they must be placed in brackets.
Boolean expressions are not necessarily simplified so they must follow the rules set down by the file format. If test commands are to be ORred together, they must be placed in brackets.


<syntax type="C++">
<source lang="cpp">
if ((isset(f1) || isset(f2)) {
if ((isset(f1) || isset(f2)) {
   ......
   ......
Line 103: Line 103:


if (isset(1) || (isset(2) && isset(3))) {    is NOT legal
if (isset(1) || (isset(2) && isset(3))) {    is NOT legal
</syntax>
</source>


Depending on the compiler, simplification of boolean expressions may be supported, so the above may not apply in all cases (although if these are rules are followed then the logic will work with all compilers).
Depending on the compiler, simplification of boolean expressions may be supported, so the above may not apply in all cases (although if these are rules are followed then the logic will work with all compilers).
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Substitutions for the following test commands are available:
Substitutions for the following test commands are available:


<syntax type="C++">
<source lang="cpp">
equaln(v30,4)      v30 == 4
equaln(v30,4)      v30 == 4
equalv(v30,v32)    v30 == v32
equalv(v30,v32)    v30 == v32
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!lessn(v30,4)      v30 = 4
!lessn(v30,4)      v30 = 4
!lessv(v30,v32)    v30 = v32
!lessv(v30,v32)    v30 = v32
</syntax>
</source>


Also, flags can be tested for by just using the name of the flag:
Also, flags can be tested for by just using the name of the flag:


<syntax type="C++">
<source lang="cpp">
if (f6) { .....
if (f6) { .....


if (v7 > 0 && !f6) { .....
if (v7 > 0 && !f6) { .....
</syntax>
</source>


which is equivalent to:
which is equivalent to:


<syntax type="C++">
<source lang="cpp">
if (isset(f6)) { .....
if (isset(f6)) { .....


if (v7 > 0 && !isset(f6)) { .....
if (v7 > 0 && !isset(f6)) { .....
</syntax>
</source>


== Argument types ==
== Argument types ==
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Compilers can enforce type checking, so that the programmer must use the correct prefix for an argument so that they know they are using the right type. Decoders should display arguments with the right type.
Compilers can enforce type checking, so that the programmer must use the correct prefix for an argument so that they know they are using the right type. Decoders should display arguments with the right type.


<syntax type="C++">
<source lang="cpp">
move.obj(o4, 80, 120, 2, f66);
move.obj(o4, 80, 120, 2, f66);


if (obj.in.box(o2, 30, 60, 120, 40)) { .....
if (obj.in.box(o2, 30, 60, 120, 40)) { .....
</syntax>
</source>


For a complete list of the commands and their argument types, see [[AGIWiki/Logic commands by name|Logic commands by name]].
For a complete list of the commands and their argument types, see [[AGIWiki/Logic commands by name|Logic commands by name]].
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Messages and inventory items may be given in either numerical or text format:
Messages and inventory items may be given in either numerical or text format:


<syntax type="C++">
<source lang="cpp">
print("He's not here.");
print("He's not here.");


Line 211: Line 211:
if (has(i9)) { .....
if (has(i9)) { .....


</syntax>
</source>
Messages can also be split over multiple lines:
Messages can also be split over multiple lines:


<syntax type="C++">
<source lang="cpp">
print("This message is split "
print("This message is split "
       "over multiple lines.");
       "over multiple lines.");
</syntax>
</source>


Quote marks must be used around messages and inventory item names. This is important because some messages or inventory item names may contain parentheses or commas, which could confuse the compiler. This is also the case for the said command which will be described shortly.
Quote marks must be used around messages and inventory item names. This is important because some messages or inventory item names may contain parentheses or commas, which could confuse the compiler. This is also the case for the said command which will be described shortly.


<syntax type="C++">
<source lang="cpp">
if (has("Buckazoid(s)")) { .....  // no ambiguity here about where
if (has("Buckazoid(s)")) { .....  // no ambiguity here about where
                                   // the argument ends
                                   // the argument ends
</syntax>
</source>


If quote marks are part of the message or inventory object, a \ should be placed in front of these. To use a \, \\ should be used. \n can also be used for a new line.
If quote marks are part of the message or inventory object, a \ should be placed in front of these. To use a \, \\ should be used. \n can also be used for a new line.
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The said test command uses different parameters to all the other commands. Where as the others use 8 bit arguments (0-255), said takes 16 bit arguments (0-65535). Also, the number of arguments in a said command can vary. The numbers given in the arguments are the word group numbers from the WORDS.TOK file.
The said test command uses different parameters to all the other commands. Where as the others use 8 bit arguments (0-255), said takes 16 bit arguments (0-65535). Also, the number of arguments in a said command can vary. The numbers given in the arguments are the word group numbers from the WORDS.TOK file.


<syntax type="C++">
<source lang="cpp">
if (said(4, 80)) { .....
if (said(4, 80)) { .....
</syntax>
</source>


Words can also be given in place of the numbers:
Words can also be given in place of the numbers:


<syntax type="C++">
<source lang="cpp">
if (said("look")) { .....
if (said("look")) { .....


if (said("open","door")) { .....
if (said("open","door")) { .....
</syntax>
</source>


Quote marks must also be used around the words.
Quote marks must also be used around the words.
Line 248: Line 248:
Labels are given like this:
Labels are given like this:


<syntax type="C++">
<source lang="cpp">
Label1:
Label1:
</syntax>
</source>


The label name can contain letters, numbers, and the characters '_' and '.'. No spaces are allowed.
The label name can contain letters, numbers, and the characters '_' and '.'. No spaces are allowed.
Line 256: Line 256:
The [[AGIWiki/Goto|Goto]] command takes on parameter, the name of a label:
The [[AGIWiki/Goto|Goto]] command takes on parameter, the name of a label:


<syntax type="C++">
<source lang="cpp">
goto(Label1);
goto(Label1);
</syntax>
</source>


== Comments ==
== Comments ==
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There are three ways that comments can be used.
There are three ways that comments can be used.


<syntax type="C++">
<source lang="cpp">
// - rest of line is ignored
// - rest of line is ignored


Line 270: Line 270:


/* Text between these are ignored */
/* Text between these are ignored */
</syntax>
</source>


The /*...*/ can be nested:
The /*...*/ can be nested:


<syntax type="C++">
<source lang="cpp">
/* comment start
/* comment start


Line 288: Line 288:


*/                  // uncomments
*/                  // uncomments
</syntax>
</source>


'''Note:''' the fact that these comments can be nested is very different from almost every other language that uses these types of comments, including C, C , and Java.
'''Note:''' the fact that these comments can be nested is very different from almost every other language that uses these types of comments, including C, C , and Java.
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In some cases you may want to assign a specific number to a message so you can refer to it in other places. This is done by using the #message command, followed by the number of the message then the message itself:
In some cases you may want to assign a specific number to a message so you can refer to it in other places. This is done by using the #message command, followed by the number of the message then the message itself:


<syntax type="C++">
<source lang="cpp">
#message 4 "You can't do that now."
#message 4 "You can't do that now."
</syntax>
</source>


Then you can give the message number as the parameter in commands:
Then you can give the message number as the parameter in commands:


<syntax type="C++">
<source lang="cpp">
print(m4);
print(m4);
</syntax>
</source>


Or embed the message in commands as normal and the number you assigned to it before will be used:
Or embed the message in commands as normal and the number you assigned to it before will be used:


<syntax type="C++">
<source lang="cpp">
print("You can't do that now.");
print("You can't do that now.");
</syntax>
</source>


<nowiki>#message can be used anywhere in the file, so you do not have to set the message before you use it. </nowiki>
<nowiki>#message can be used anywhere in the file, so you do not have to set the message before you use it. </nowiki>
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