Scripting language bundle - Revision history

Stefan Urbanek: Added proposed changes

2005-08-30T14:25:37Z

Added proposed changes

Stefan Urbanek: /* Implementation */

2005-02-18T08:51:50Z

Implementation

Stefan Urbanek at 08:47, 18 February 2005

2005-02-18T08:47:34Z

Stefan Urbanek: /* Implementation */

2005-02-18T08:46:49Z

Implementation

Stefan Urbanek at 08:46, 18 February 2005

2005-02-18T08:46:32Z

New page

Scripting language bundle is, well, a bundle that offers a language for [[StepTalk]]. The bundle provides mechanisms for understanding the language and interpreting it.

Core of a language bundle is a scripting engine. Each language should have its own engine that executes scripts. The engine should take into account a context, where the script will be executed, and the script itself. After the execution, the engine should provide some feedback, for example a result object or it should throw an exception when something went wrong.

Few steps for creating a custom language bundle:

# take a language template from StepTalk sources or create one of your own
# create your own language engine as a subclass of the [[STEngine]]
# implement method ''executeCode:inEnvironment:''
# provide an information list about the bundle

=== Language Template ===

Template for a language bundle can be found [http://stefan.agentfarms.net/Download/GNUstep/MyLanguage-20041021.tar.gz here].

=== Implementation ===

Header file for a custom language should look like this:

#import <StepTalk/STEngine.h>

@interface MyLanguageEngine:STEngine
{
/* ... */
}
@end

And the implementation:

#import "MyLanguageEngine.h"

@implementation !MyLanguageEngine
- (id) executeCode:(NSString *)sourceCode
inEnvironment:(STEnvironment *)env
{
id retval = nil;

/* execute the code sourceCode using environment env */

/* retval = return value from the interpreter; */
return retval;
}
@end

You may want to use ''[environment objectDictionary]'' to get all environment's named objects.

To translate a selector (for example a symbolic selector) you can use ''[environment translateSelector:aString forReceiver:anObject]'' which returns a [[NSString]] containing translated selector or nil if the selector should not be sent (because it should be fobidden by the environment). Moreover you should use this method if you want to use restrictions of selectors of the scripting envornment. See [[STEnvironment]] and [[STEnvironmentDescription]] for more information.

If your language can execute scripts from files, you may specify the file type in the MyLanguageInfo.plist. Then script manager and [[StepTalk]] tools can execute files with an appropriate language engine.

{
/* Array of file types of your language scripts */
STFileTypes = ( "mylang" );
}

@@ Line 53: / Line 53: @@
       STFileTypes = ( "mylang" );
+  }
 [[Category:Scripting]]

← Older revision		Revision as of 08:47, 18 February 2005
Line 53:		Line 53:
	STFileTypes = ( "mylang" );		STFileTypes = ( "mylang" );
	}		}
		+
		+	[[Category:Scripting]]

@@ Line 29: / Line 29: @@
   #import "MyLanguageEngine.h"
-−
   @implementation MyLanguageEngine
   - (id)  executeCode:(NSString *)sourceCode