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trsplit

Summary

Split a combined Antlr4 grammar

Description

The split command splits one grammar into two. The input grammar must be a combined lexer/parser grammar implemented in one file. The transformation creates a lexer grammar and a parser grammar, outputed as parse tree data with the two grammars. trsponge is used to instantiate the two files in the file system.

Usage

trsplit

Details

The trsplit application splits a combined grammar into two files. It does this as follows:

  • Partition the rules in the grammar into parser and lexer rules. This is done by examining the LHS symbol: parser rules start with a lowercase LHS symbol name; lexer rules start with an uppercase LHS symbol name.
  • In the parser grammar, insert an optionsSpec declaration that contains a tokenVocab specification for the name of the vocabulary generated for the lexer grammar.
  • Add grammarDecl statements to the top of the new files to declare the parser and lexer grammars.

After splitting, use trsponge to output the files. The resulting files may require hand-tweaking due to various constraints that split grammars must follow, including:

  • String literals that do not have a corresponding lexer rule must be modified.
  • Parser options do not apply to lexer grammars. Remove or replace.

Example

trparse Arithmetic.g4 | trsplit | trsponge

Current version

0.23.17 Fix trgen Cpp target.

License

The MIT License

Copyright (c) 2024 Ken Domino

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.