Han-Wen Nienhuys <[EMAIL PROTECTED]> writes:
>
> Right now, parser.yy sets the input location of music expressions
> directly (using set_spot()). This method is flawed, since the parser
> occasionally has to look ahead for parsing correctly, thus putting the
> origin property in the wrong spot. If you want to attack this problem,
> you would have to modify the lexer to store the exact input locations
> of each token (including the end); there's no need to store the input
> string itself, since that is defined by the begin and end pointer of
> the token. (Locations are stored as pointers into a memory copy of the
> input file.)
>
> Then it should not be hard to make the parser use the location of
> every token. A music expression is located at the start/end of its
> tokens.
Would that mean to change the token types from
%union {
Book *book;
Output_def *outputdef;
SCM scm;
String *string;
Music *music;
Score *score;
int i;
}
to something like:
%union {
Book *book;
Output_def *outputdef;
SCM scm;
String *string;
Music *music;
Score *score;
int i;
SCM_token *scm_token;
String_token *string_token;
int_token *i_token;
}
with for instance;
struct String_token {
String *val;
Input origin;
Input end;
} /* or a set of classes */
Then in the lexer:
*yylval.string_token->val = YYText ();
*yylval.string_token->origin = ???;
*yylval.string_token->end = ???;
?
In order to propagate origins to non-terminals, other (non-terminal)
types should also have the origin and end fields.
Am I missing something more straightforward?
nicolas
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