trcombine 0.13.6

This package has no dependencies.

# trcombine
Combine two grammars into one.
One grammar must be a lexer grammar, the other a parser grammar,
order is irrelevant. The output is parse tree data.
# Usage
trcombine <grammar1> <grammar2>
# Details
`trcombine` combines grammars that are known as "split grammars"
(separate Antlr4 lexer and parser grammars)
into one grammar, known as a "combined grammar". This refactoring is
useful if a simplified grammar grammar is wanted, and if possible if
the split grammar does not use the "superClass" option in one or the other
grammars. The opposite refactoring is implemented by
[trsplit](https://github.com/kaby76/Domemtech.Trash/tree/main/trsplit).
The split refactoring performs several operations:
* Combine the two files together, parser grammar first, then lexer grammar.
* Remove the `grammarDecl` for the lexer rules, and change the `grammarDecl`
for the parser rules to be a combined grammar declaration. Rename the name
of the parser grammar to not have "Parser" at the tail of the name.
* Remove the `optionsSpec` for the lexer section.
* Remove any occurrence of "tokenVocab" from the `optionsSpec` of the parser section.
* If the `optionsSpec` is empty, it is removed.
The order of the two grammars is ignored: the parser rules always will appear
before the lexer rules.
Lexer modes will require manual fix-up.
# Example
Consider the following grammar that is split.
_Input to command_
Lexer grammar in ExpressionLexer.g4:
lexer grammar ExpressionLexer;
VARIABLE : VALID_ID_START VALID_ID_CHAR* ;
fragment VALID_ID_START : ('a' .. 'z') | ('A' .. 'Z') | '_' ;
fragment VALID_ID_CHAR : VALID_ID_START | ('0' .. '9') ;
INT : ('0' .. '9')+ ;
MUL : '*' ;
DIV : '/' ;
ADD : '+' ;
SUB : '-' ;
LP : '(' ;
RP : ')' ;
WS : [ \r\n\t] + -> skip ;
Parser grammar in ExpressionParser.g4:
parser grammar ExpressionParser;
e : e ('*' | '/') e
| e ('+' | '-') e
| '(' e ')'
| ('-' | '+')* a
;
a : number | variable ;
number : INT ;
variable : VARIABLE ;
_Command_
trcombine ExpressionLexer.g4 ExpressionParser.g4 | trprint > Expression.g4
Combined grammar in Expression.g4:
grammar Expression;
e : e ('*' | '/') e
| e ('+' | '-') e
| '(' e ')'
| ('-' | '+')* a
;
a : number | variable ;
number : INT ;
variable : VARIABLE ;
VARIABLE : VALID_ID_START VALID_ID_CHAR* ;
fragment VALID_ID_START : ('a' .. 'z') | ('A' .. 'Z') | '_' ;
fragment VALID_ID_CHAR : VALID_ID_START | ('0' .. '9') ;
INT : ('0' .. '9')+ ;
MUL : '*' ;
DIV : '/' ;
ADD : '+' ;
SUB : '-' ;
LP : '(' ;
RP : ')' ;
WS : [ \r\n\t] + -> skip ;
The original grammars are left unchanged.
# Current version
0.13.6 -- updates to trgen for Go.