PEG:

Vocabulary

peg

Syntax

PEG: word ( stack -- effect ) definition... ;

Word description

Defines a word that when called will parse a string using the syntax defined by the parser created by the definition. The definition should have stack effect ( -- parser ) and the created word ( string -- ast ). In contrast to calling the parser resulting from the definition with parse, the parser is pre-compiled and not compiled for each invocation of parse. If the parsing fails, the word throws an exception.

Definition

USING: accessors compiler.units effects.parser kernel
locals.backend sequences words ;

IN: peg

SYNTAX: PEG:
    (:) 3 load-locals -1 get-local -2 get-local 0 get-local [
        3 load-locals -2 get-local -1 get-local 0 get-local [
            3 load-locals -2 get-local call compile load-local
            -2 get-local 0 get-local -2 get-local [
                2 load-locals -1 get-local [
                    load-local 0 get-local compiled-parse
                    1 drop-locals
                ] curry [ ast>> ] 0 get-local [
                    load-local 0 get-local parse-failed
                    1 drop-locals
                ] curry ?if 2 drop-locals
            ] curry curry -1 get-local define-declared
            4 drop-locals
        ] curry curry curry with-compilation-unit 3 drop-locals
    ] curry curry curry append! 3 drop-locals ;