[antlr-interest] Seeking advice - 2 questions using ANTLR

[Frank Font]

Hi Mark,

Wow, you put these things together fast!  (Quicker than I can try them out.)

Okay, I ran this in ANTLRWorks 1.1.5 and am getting error messages in 
the "output" window...

line 2:5 no viable alternative at character 'C'
line 1:0 no viable alternative at input 'IF'

These messages are a mystery to me and I get gobbs of them with my other 
grammars.

Also, I don't see the translated output anywhere although the parse tree 
looks good.

Any insight?

Regards,
Frank

Mark Volkmann wrote:
> Here's a version of the grammar that I believe produces the output you
> want. Note that it is currently limited to logical expressions with a
> single "AND" or "OR". If anyone sees ways to improve what I've done
> I'd love to get feedback on this. I'm still learning ANTLR.
>
> grammar Accounting;
>
> options {
>   output = template;
> }
>
> @lexer::header { package com.ociweb.accounting; }
> @parser::header { package com.ociweb.accounting; }
>
> @parser::members {
>   private void out(String text) { System.out.print(text); }
>   private void outln(String text) { System.out.print(text); }
> }
>
> start: ifStatement EOF;
>
> ifBegin: 'IF' { out("IF("); };
> ifEnd: 'END IF' { out(")"); };
>
> ifStatement
>   : ifBegin condition 'THEN' statement ('ELSE' statement)? ifEnd;
>
> comparison
>   : expression RELATIONAL_OPERATOR expression;
>
> condition
>   : c1=comparison { out($c1.text); }
>   | c1=comparison lo=LOGICAL_OPERATOR c2=comparison
>     {
>       out($lo.text + "(" + $c1.text + ", " + $c2.text + ")");
>     }
>   ;
>
> expression
>   : STRING_LITERAL
>   | value (SIGN value)*
>   ;
>
> statement
>   @init { out(", "); }
>   : e=expression { out($e.text); }
>   | ifStatement
>   ;
>
> value: NAME | NUMBER;
>
> LOGICAL_OPERATOR: 'AND' | 'OR';
>
> RELATIONAL_OPERATOR: '<' | '<=' | '=' | '>=' | '>';
>
> APOSTROPHE: '\'';
>
> NUMBER: INTEGER | FLOAT;
> fragment FLOAT: INTEGER '.' NATURAL_NUMBER;
> fragment INTEGER: SIGN? NATURAL_NUMBER;
> fragment NATURAL_NUMBER: '0' | '1'..'9' '0'..'9'*;
> SIGN: '+' | '-';
>
> NAME: LETTER (LETTER | NUMBER | '_')*;
>
> STRING_LITERAL: APOSTROPHE NONCONTROL_CHAR* APOSTROPHE;
>
> WHITESPACE: (NEWLINE | SPACE)+ { $channel = HIDDEN; };
>
> // Note that NONCONTROL_CHAR does not include the double-quote character.
> fragment NONCONTROL_CHAR: LETTER | DIGIT | SYMBOL | SPACE;
> fragment LETTER: LOWER | UPPER;
> fragment LOWER: 'a'..'z';
> fragment UPPER: 'A'..'Z';
> fragment DIGIT: '0'..'9';
> fragment NEWLINE: '\r'? '\n';
> fragment SPACE: ' ' | '\t';
>
> // Note that SYMBOL does not include the
> // apostrophe or double-quote characters.
> fragment SYMBOL: '!' | '#'..'&' | '('..'/' | ':'..'@' | '['..'`' | '{'..'~';
>
>
> On Jan 17, 2008 3:55 PM, Mark Volkmann <r.mark.volkmann at gmail.com> wrote:
>   
>> Here's a start on your grammar.
>>
>> grammar Accounting;
>>
>> options {
>>   output = template;
>> }
>>
>> @lexer::header { package com.ociweb.accounting; }
>> @parser::header { package com.ociweb.accounting; }
>>
>> start: ifStatement EOF;
>>
>> ifStatement
>>   : 'IF' condition 'THEN' statement ('ELSE' statement)? 'END IF';
>>
>> comparison: expression RELATIONAL_OPERATOR expression;
>>
>> condition: comparison (LOGICAL_OPERATOR comparison)*;
>>
>> expression
>>   : STRING_LITERAL
>>   | value (SIGN value)*;
>>
>> statement: expression | ifStatement;
>>
>> value: NAME | NUMBER;
>>
>> LOGICAL_OPERATOR: 'AND' | 'OR';
>>
>> RELATIONAL_OPERATOR: '<' | '<=' | '=' | '>=' | '>';
>>
>> APOSTROPHE: '\'';
>>
>> NUMBER: INTEGER | FLOAT;
>> fragment FLOAT: INTEGER '.' NATURAL_NUMBER;
>> fragment INTEGER: SIGN? NATURAL_NUMBER;
>> fragment NATURAL_NUMBER: '0' | '1'..'9' '0'..'9'*;
>> SIGN: '+' | '-';
>>
>> NAME: LETTER (LETTER | NUMBER | '_')*;
>>
>> STRING_LITERAL: APOSTROPHE NONCONTROL_CHAR* APOSTROPHE;
>>
>> WHITESPACE: (NEWLINE | SPACE)+ { $channel = HIDDEN; };
>>
>> // Note that NONCONTROL_CHAR does not include the double-quote character.
>> fragment NONCONTROL_CHAR: LETTER | DIGIT | SYMBOL | SPACE;
>> fragment LETTER: LOWER | UPPER;
>> fragment LOWER: 'a'..'z';
>> fragment UPPER: 'A'..'Z';
>> fragment DIGIT: '0'..'9';
>> fragment NEWLINE: '\r'? '\n';
>> fragment SPACE: ' ' | '\t';
>>
>> // Note that SYMBOL does not include the
>> // apostrophe or double-quote characters.
>> fragment SYMBOL: '!' | '#'..'&' | '('..'/' | ':'..'@' | '['..'`' | '{'..'~';
>>
>> It parses your example input except for I changed "H-CAPRESTATE" to
>> "H_CAPRESTATE" to simply things. This way I can use "-" for
>> subtraction. I'm sure there's a way to work this out so you can also
>> use "-" in names.
>>
>> The grammar above doesn't output anything. It just verifies that input conforms.
>>
>> Email me privately if you want the Java code I wrote that uses the
>> generated classes and my Ant build file.
>>
>>
>> On Jan 17, 2008 3:02 PM, Mark Volkmann <r.mark.volkmann at gmail.com> wrote:
>>     
>>> On Jan 17, 2008 2:04 PM, Frank Font <mrfont at room4me.com> wrote:
>>>       
>>>> Hello,
>>>>
>>>> I purchased the book, read through it, but I have a thick skull.
>>>> Perhaps I can get some advice here on two questions about converting
>>>> formula expressions that look like "basic" syntax...
>>>>
>>>> IF REP_DTE > '2001-01-01' AND ATOTAL>100 THEN
>>>>     H-CAPRESTATE
>>>> ELSE
>>>>     IF REP_DTE < '2001-01-01' THEN
>>>>         ACCTG_CNG + ACCTG_ERR_CRCT
>>>>     END IF
>>>> END IF
>>>>
>>>> Into a flat format that looks like Excel formula syntax...
>>>>
>>>> IF( AND(REP_DTE > '2001-01-01',ATOTAL>100), H-CAPRESTATE, IF(REP_DTE <
>>>> '2001-01-01', ACCTG_CNG + ACCTG_ERR_CRCT)
>>>>
>>>> I tried writing a few grammar files, but all have had various runtime
>>>> issues.
>>>>
>>>> Here are my questions...
>>>>
>>>> 1.  Is ANTLR the right tool for this job?  (I don't have much time.)
>>>>         
>>> ANTLR can definitely do this. However, you shouldn't expect the work
>>> to go quickly if this is your first ANTLR grammar. You'll be learning
>>> lots of things along the way.
>>>
>>>       
>>>> 2.  If it is the right tool, is there already a grammar that will get me
>>>> most of the way there?
>>>>         
>>> I'm not aware of a particular existing grammar that is close to what
>>> you want. Maybe someone else knows of one.
>>>
>>>
>>>       
>>>> Thanks in advance for any advice.
>>>>
>>>> Regards,
>>>> Frank Font
>>>>         
>>> --
>>> R. Mark Volkmann
>>> Object Computing, Inc.
>>>
>>>       
>>
>> --
>> R. Mark Volkmann
>> Object Computing, Inc.
>>
>>     
>
>
>
>