Hi, I have never considered using tree grammar earlier. But now I took a look at it as it sounded like a solution to my problem. But I still have one doubt.
Suppose I write a grammar that parses the input file and constructs the AST. I have to next write a tree grammar that can operate on the generated AST (I guess this is called the tree walkers). My question is, is it possible to turn on rewrite in tree grammar? or it is necessary to describe the entire tree in the tree-grammar? I did some googling and found this page - http://www.antlr.org/wiki/display/~admin/2008/11/29/Woohoo%21+Tree+pattern+matching%2C+rewriting+a+reality . This sounds damn sexy! But has this been released? Does the latest release (3.1.2) include this? Thanks, Indhu ----- Original Message ----- From: Sam Harwell <[email protected]> To: Indhu Bharathi <[email protected]>, [email protected] Sent: Thursday, March 5, 2009 8:34:25 AM GMT+0530 Asia/Calcutta Subject: RE: [antlr-interest] Seperating grammar and actions You have a few options: 1. Only build an AST in the parser, then use a tree walker to perform your needed operations. This is the “v3” way to do it, especially with the new filter-mode tree parsers on the way. 2. Call virtual functions from your actions, and implement those functions as empty stubs. Derive a class from the parser and implement the functions as necessary. This seems to be a “v2” way to do it, as it’s used in one of the v2 grammars in the ANTLR Tool. Sam From: [email protected] [mailto:[email protected]] On Behalf Of Indhu Bharathi Sent: Wednesday, March 04, 2009 8:44 PM To: [email protected] Subject: [antlr-interest] Seperating grammar and actions Hi, Is there a way to separate grammar and actions into two different files? This will be helpful when multiple people are working with the same grammar file (each might write their own actions for the same production) and don’t want to create redundant copies of the grammar file. One way I thought was to implement observer pattern. The parser will be the subject and multiple observers can register to the same production and do different things. Another way would be to write a tool to separate the actions from the grammar file and reattach it. This way, actions can be separated out and maintained in a separate file and can be reattached when necessary and changes to grammar can be done in one centralized file. Is there any other way to do this? Any hint might be useful. Thanks, Indhu --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "il-antlr-interest" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en -~----------~----~----~----~------~----~------~--~---
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