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Re: Parsing a language with optional spaces


From: Maury Markowitz
Subject: Re: Parsing a language with optional spaces
Date: Mon, 6 Jul 2020 16:01:11 -0400

> On Jul 6, 2020, at 3:23 PM, Akim Demaille <akim@lrde.epita.fr> wrote:
> 
> FOR/{sp}{id}{sp}={sp}{num}{sp}TO{sp}{num}  { printf("for: %s\n", yytext); }

This is a very different style than what I have seen in the past. In the past, 
most examples of flex tend to match against the tokens as individual items and 
return immediately so that bison can do the grammar check and generation. So in 
my existing (semi-working) .l, I followed this style and produced:

    FOR { return FOR; }
    ...
    TO  { return TO; }

Then over in my .y I have:

    FOR variable '=' expression TO expression

Using your method, what would the associated bison look like? Just a single 
item matching the entire line?


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