[antlr-interest] How to use lexer getCharPositionInLine() function in Cpp target

[Richard Gildea]

Another problem I have found with the Cpp target compared to the C target
is when trying to use a construct such as $start=theStart (see e.g.
http://antlr.markmail.org/message/izyhuzbooerfw4tu), which gives the
following compiler error:

error: expression is not assignable
             this->get_state()->get_tokenStartCharIndex() = theStart;
this->emit();
             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^

Cheers,

Richard


On 16 October 2012 14:56, Richard Gildea <rgildea at gmail.com> wrote:

> Hi Gokul,
>
> This does not work either, as I now get the following compiler error in
> the generated lexer rule functions:
>
> error: use of undeclared identifier 'm_ctx'
>
> Cheers,
>
> Richard
>
> On 15 October 2012 17:56, Gokulakannan Somasundaram <gokul007 at gmail.com>wrote:
>
>> You don't need to write it inside the Cpp file. Just write it in the
>> grammar.
>>
>> Gokul.
>>
>>
>> On Tue, Oct 16, 2012 at 8:56 AM, Gokulakannan Somasundaram <
>> gokul007 at gmail.com> wrote:
>>
>>> Yeah. That looks like a bug. I will need to change the stg file. For
>>> now, you can directly write m_ctx->getCharPositionInLine() in place of getCharPositionInLine()
>>> and let me know, whether it works.
>>>
>>> Thanks,
>>> Gokul.
>>>
>>> On Tue, Oct 16, 2012 at 8:28 AM, Richard Gildea <rgildea at gmail.com>wrote:
>>>
>>>> Hi Gokul,
>>>>
>>>> The problem is that the predicate also appears in one of the generated
>>>> TLexerCyclicDFA functions, leading to the following compilation error:
>>>>
>>>> error: no member named 'getCharPositionInLine' in 'cifLexerCyclicDFA33'
>>>>                             if ( (( this->getCharPositionInLine() > 0
>>>> )) )
>>>>                                     ~~~~  ^
>>>>
>>>> Manually editing the generated code to read
>>>> ctx->getCharPositionInLine() fixes the compilation.
>>>>
>>>> Cheers,
>>>>
>>>> Richard
>>>>
>>>>
>>>> On 15 October 2012 17:13, Gokulakannan Somasundaram <gokul007 at gmail.com
>>>> > wrote:
>>>>
>>>>> getCharPositionInLine() function is present inside Lexer. You can just
>>>>> call it as similar to Java.
>>>>> just replace the MACRO GETCHARPOSITIONINLINE() with
>>>>> this->getCharPositionInLine() ?
>>>>>
>>>>> I can't understand second part of your question.
>>>>>
>>>>> Thanks,
>>>>> Gokul.
>>>>>
>>>>>
>>>>> On Tue, Oct 16, 2012 at 2:43 AM, Richard Gildea <rgildea at gmail.com>wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I am attempting to convert my parser to use the Cpp target after
>>>>>> previously
>>>>>> using the C target for some time, and have come across a problem
>>>>>> trying to
>>>>>> call the function TLexer::getCharPositionInLine() inside a gated
>>>>>> semantic
>>>>>> predicate in one of my lexer rules. With the C target I was using a
>>>>>> construct such as
>>>>>>
>>>>>> ({ GETCHARPOSITIONINLINE() > 0 }?=> ';')
>>>>>>
>>>>>> to identify a semicolon character in the first column of a line. When
>>>>>> trying to use a similar construct with the Cpp target, in the
>>>>>> generated
>>>>>> code this predicate is used both inside the lexer rule, where the
>>>>>> correct
>>>>>> usage would be this->getCharPositionInLine(), and inside a cyclicDFA,
>>>>>> where
>>>>>> the usage would be ctx->getCharPositionInLine(). Is there a way to
>>>>>> use such
>>>>>> a predicate with the Cpp target?
>>>>>>
>>>>>> Cheers,
>>>>>>
>>>>>> Richard
>>>>>>
>>>>>> List: http://www.antlr.org/mailman/listinfo/antlr-interest
>>>>>> Unsubscribe:
>>>>>> http://www.antlr.org/mailman/options/antlr-interest/your-email-address
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>