Thanks for the clarification, now it is much clearer!
thSoft
On 2010.03.08., at 11:03, Bertalan Fodor (LilyPondTool) wrote:
> The lexer reads regular expressions, and tries to match them to a rule. A
> rule will return a token and a value (yylval). These two will be used by the
> parser to interpret the input.
> This is so simple.
> So for example how a note name is recognized:
> a note name like fs will be read as [a-zA-Z\200-\377]+ regular expression
> (ALPHAWORD in lexer.ll).
> In notes and figure lexer state (<notes, figures> in lexer.ll) it will return
> scan_bare_word, based on the rule:
> <notes,figures>{
> {ALPHAWORD} {
> return scan_bare_word (YYText ());
> }
>
>
> scan_bare_word is a function that takes the matched input and return the
> appropriate token and set the appropriate value in yylval. Look at the
> implementation of this function to understand how that token is actually
> generated.
>
> Bert
>
>
>
> Harmath Dénes wrote:
>> On 2010.03.04., at 19:36, Patrick McCarty wrote:
>>
>>
>>
>>> 2010/3/4 Harmath Dénes <harmathde...@gmail.com>
>>> :
>>>
>>>
>>>> Greetings all,
>>>>
>>>> it's great to have a grammar of LilyPond in the NR! But there are terminal
>>>> rules which are not strings (BOOK_IDENTIFIER, CHORD_MODIFIER etc.). Where
>>>> can their definitions be learned?
>>>>
>>>>
>>> If you do a `git grep' for them in the source tree, you will see that
>>> many of these terminals come to life in the lexing stage.
>>>
>>>
>>
>> I see. The -p option gives even more useful output.
>>
>>
>>
>>> For example, BOOK_IDENTIFIER is the return value of
>>> Lily_lexer::try_special_identifiers() in lily/parser.yy, but only if
>>> its second argument is a Book smob.
>>>
>>> -Patrick
>>>
>>>
>>
>> It's not exactly clear to me how lexing and parsing are related, since there
>> are lexer rules (e.g. NOTENAME_PITCH) which can be set from Scheme code.
>> Could someone shed a light on this?
>>
>> Thanks,
>> thSoft
>>
>> _______________________________________________
>> lilypond-devel mailing list
>>
>> lilypond-devel@gnu.org
>> http://lists.gnu.org/mailman/listinfo/lilypond-devel
>>
>>
>>
>>
>
_______________________________________________
lilypond-devel mailing list
lilypond-devel@gnu.org
http://lists.gnu.org/mailman/listinfo/lilypond-devel
