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Support lex-style definitions #417

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Support lex-style definitions#417

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@FranklinChen
FranklinChen
opened on Aug 30, 2023

I didn't see a way to do the following that can be done in lex:

DIGIT    [0-9]
ID       [a-z][a-z0-9]*
NUMBER {DIGIT}+"."{DIGIT}*

%%

{NUMBER} ...

so that patterns can be composed in definitions and definitions can be used in rules.

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  1. ltratt commented on Aug 30, 2023

    @ltratt
    ltratt
    on Aug 30, 2023
    Member

    Yes, this isn't currently supported. Given that we currently use the Rust regex crate, if we wanted to do something like this, we'd have some interesting fun and games getting escaping right. So a basic version is pretty easy; a version with good error messages might be challenging.

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