NAME

Grammer::Debugger - Interactive debugger for Raku grammars

SYNOPSIS

In the file that has your grammar definition, merely load the module in the same lexical scope:

use Grammar::Debugger;

grammar Some::Grammar { ... }

DESCRIPTION

Grammar::Debugger is an interactive debugger for Raku grammars. It applies to all grammars in its lexical scope. When you run your program and start to parse a grammar, you should get an interactive prompt. Type h to get a list of commands:

$ raku my-grammar-program.raku
TOP
> h
    r              run (until breakpoint, if any)
    <enter>        single step
    rf             run until a match fails
    r <name>       run until rule <name> is reached
    bp add <name>  add a rule name breakpoint
    bp list        list all active rule name breakpoints
    bp rm <name>   remove a rule name breakpoint
    bp rm          removes all breakpoints
    q              quit
>

If you are debugging a grammar and want to set up breakpoints in code rather than entering them manually at the debug prompt, you can apply the breakpoint trait to any rule:

token name is breakpoint {
    \w+ [\h+ \w+]*
}

If you want to conditionally break, you can also do something like:

token name will break { $_ eq 'Raku' } {
    \w+ [\h+ \w+]*
}

Which will only break after the name token has matched "Raku".

AUTHOR

Jonathan Worthington

COPYRIGHT AND LICENSE

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.