[antlr-interest] String template questions.

[Terence Parr]

On Apr 7, 2008, at 9:21 AM, PSheehan at decaresystems.ie wrote:

>
> I've got a simple grammar up and running which generates Java beans  
> and Hibernate config files.  I have a few questions as I'm not  
> really sure if I am going about things in the correctly way.  My  
> solution uses a lexer and parser to create an AST which I then pass  
> on to a tree walker for the generation of the output.
>
> 1.  How do people generally create multiple files from a single   
> tree output.  For example if the result of the tree needs to create  
> Bean1.java and Bean2.java.  Currently I've created a streamer  
> strategy which my tree walker calls when it needs be, passing the  
> output of a template to it.  The strategy then knows how to create  
> java files in the correct package structure.  I can then easily  
> change the strategy in order to write Hibernate config files.  Is  
> this a valid approach or should I just get the tree walker to roll  
> up all the template results and break them up after the walker has  
> finished.

You could create an ST "broadcaster" that emits same attributes to  
multiple templates or just set attr ofmultiple templates manually.

> 2.   I've created one entry point into my templates from my grammar  
> like so '%modeltmp($namespace,$name,$fieldDefinations)'.  Only one  
> rule in the tree walker invodes a grammar, the other rules just  
> gather the information needed to pass to the template. The main  
> reason I did this was so I could call different templates from  
> within the main template to produce different output given the same  
> input.  For example I could generate a constructor, bean properties  
> and a 'toString' method all from $fieldDefinations.    Is there a  
> better way of doing this?

That works great.

>  Should I move some of this work back into my parser so it creates,  
> in the AST, a constructor node with field definations as childern or  
> a 'toString' node with field definations as childern etc.

easier to emit multiple thigns than create multiple trees usually.

>
Ter

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