[antlr-interest] Request:External action definitions

[mzukowski at yci.com]

Someone has recently done just this, but I forget who.  I'm sure they will
pipe up.  Look at the files section on the yahoo list site, I think it is
there.

Also noweb can be used for this type of thing too.  Searching for noweb in
the list archives may uncover the one I was thinking of.

Monty

-----Original Message-----
From: Anakreon Mejdi [mailto:amejdi at ertonline.gr]
Sent: Tuesday, November 26, 2002 3:41 AM
To: antlr-interest at yahoogroups.com
Subject: [antlr-interest] Request:External action definitions


I have an idea which might make antlr better.
Instead of defining the actions in the same file with the grammar
they could be defined in other file(s).

A way this could be achived(not necessarily the best) would be:

RULE:
	'a' .. 'z' { %id; }
	;


rule
	:
	RULE { %some_id; }
	;


tree_rule
	:
		#(r:RULE { %tree_id; System.out.println("RULE matched");  }
	;


In this case antlr.Tool will be fed with the grammar file and the 
file(s)  where actions are defined.

The actions identified with a label (like %id) will be searched among 
the  action  files and the label should be replaced by the content of 
the action.

Example:
	id = {
		System.out.println("Externaly defined action");
	}
		
	tree_id = {
		System.out.println(r.getText());
	}

This could be achieved with regular expressions but would be a primitive
implementation.

I'd like to know what you think about it.
Anakreon
		


 

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