[antlr-interest] simple "find-and-replace"
Des Hartman
des at deshartman.com
Tue Feb 24 14:58:45 PST 2009
Terrence
Had a look at what you have so far on ANTLRMorph. The problem I am also
going to have is that I need to output the result using ActionScript. All
the code is for a Flex page and thus only have ActionScript available. :-(
I had a look at a possible way a parser can do it, but it is ugly (see
below). Any other way to simply replace a recognize token with another token
and spit out the original input using ActionScript???
===================================
formula returns [String value]
: (EQ)? e=expression { if($EQ.text==null) {$value = $e.value;} else
{$value = $EQ.text + $e.value;} }
;
expression returns [String value]
: e=boolExpr {$value = $e.value;}
;
boolExpr returns [String value]
: e=concatExpr {$value = $e.value;} (
( AND { if($AND.text==null) {$value += $e.value;} else {$value +=
$AND.text + $e.value;} }
| OR { if($OR.text==null) {$value += $e.value;} else {$value +=
$OR.text + $e.value;} }
| LT { if($LT.text==null) {$value += $e.value;} else {$value +=
$LT.text + $e.value;} }
| LTEQ { if($LTEQ.text==null) {$value += $e.value;} else {$value +=
$LTEQ.text + $e.value;} }
| GT { if($GT.text==null) {$value += $e.value;} else {$value +=
$GT.text + $e.value;} }
| GTEQ { if($GTEQ.text==null) {$value += $e.value;} else {$value +=
$GTEQ.text + $e.value;} }
| EQ { if($EQ.text==null) {$value += $e.value;} else {$value +=
$EQ.text + $e.value;} }
| NOTEQ { if($NOTEQ.text==null) {$value += $e.value;} else {$value +=
$NOTEQ.text + $e.value;} }
)
e=concatExpr {$value += $e.value;}
)*
;
concatExpr returns [String value]
: e=sumExpr {$value = $e.value;}
(
CONCAT { if($CONCAT.text==null) {$value += $e.value;} else {$value +=
$CONCAT.text + $e.value;} }
e=sumExpr {$value += $e.value;}
)*
Thanks
Des
2009/2/24 Terence Parr <parrt at cs.usfca.edu>
> 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
>>
>>
>> List: http://www.antlr.org/mailman/listinfo/antlr-interest
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>>
>
>
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