[antlr-interest] simple "find-and-replace"

[Terence Parr]

Leon and I are working on getting ANTLRMorph ready to release. Given a  
grammar and a script like you have below, it will do the  
transformations for you. Unfortunately it's not ready. probably  
another two, three weeks
Ter
On Feb 23, 2009, at 6:28 PM, Des Hartman wrote:

> Hi,
>
> I'm looking for a simple "find-and-replace" like way to use ANTLR to  
> convert the following back and forth:
>
> "=SUM(A,5)"   ---->   "=SUM([3],5)"
>
> and
>
> "=SUM([3],5)"   ---->   "=SUM(A,5)"
>
> I have written a lexer/parser for a user entered formula. In the  
> formula, the user references columns like in Excel and the parser  
> picks these up as localReferences (LREF). I need to convert these  
> local references into an internal reference (IREF) to speed up  
> recalculations in another part of the program. I need to preserve  
> the formula text to allow the user to come back and edit it in the  
> original local reference format.
>
> "=SUM(A,5)"   ---->   "=SUM([3],5)" - Internal reference has A in  
> position 3 in the internal Array.
>
> When the user edits this formula I need to reverse the "find-and- 
> replace" and convert IREF to LREF and present the formula back to  
> the user
>
> "=SUM([3],5)"   ---->   "=SUM(A,5)" - Internal reference has A in  
> position 3 in the internal Array.
>
>
> ==========
>
> I have been looking at StringTrees as a possible way to do this and  
> have a few questions about it:
>
> 1) Can I use it with ActionScript? I am using ActionScript for the  
> Lexer/Parser and Tree. I only see references to Java, C# and Python.
> 2) Is there a simple way to do this? Maybe a separate parser file  
> instead of a more complex Tree?
> 3) As part of the rewrite, I need to call a function that does the  
> look up to get [3] to "A" and back. Can this be inserted as part of  
> the StringTree rewrite?
>
> Here is the relevant parts of the parser
>
> operand
>     : literal
>     | localRefExpr             -> ^(LREF localRefExpr)
>     | intRefExpr             -> ^(IREF intRefExpr)
>     | LPAREN expression RPAREN     -> ^(expression)
>     ;
>
> intRefExpr
>     // ={5}. Used for internal reference
>     : '[' NUMBER ']'
>     ;
>
> localRefExpr
>     // =A. Used for Formula editing to give Excel feel
>     : NAME
>     ;
>
> NAME     : LETTER*
>     ;
>
> NUMBER    :
>     ('0' .. '9')+ '.' ('0' .. '9')+ Exponent?
>     |   '.' ( '0' .. '9' )+ Exponent?
>     |   '0'..'9' ('0'..'9')* Exponent?
>         ;
>
> fragment
> Exponent
>     :   ( 'e' | 'E' ) ( '+' | '-' )? ( '0' .. '9' )+
>     ;
>
> fragment
> LETTER
>     : ('a'..'z') | ('A'..'Z')
>
> Thanks
> Des
>
>
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