Difference between revisions of "32v 1m yacc"
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== NAME == | == NAME == | ||
| − | + | yacc - yet another compiler-compiler | |
== SYNOPSIS == | == SYNOPSIS == | ||
| − | + | yacc [ -vd ] grammar | |
== DESCRIPTION == | == DESCRIPTION == | ||
| − | + | '''Yacc''' converts a context-free grammar into a set of tables for a simple automaton which executes an LR(1) parsing algorithm. The grammar may be ambiguous; specified precedence rules are used to break ambiguities. | |
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| − | + | The output file, '''y.tab.c''', must be compiled by the C compiler to produce a program '''yyparse'''. This program must be loaded with the lexical analyzer program, '''yylex''', as well as main and '''yyerror''', an error handling routine. These routines must be supplied by the user; '''Lex'''(1) is useful for creating lexical analyzers usable by '''yacc'''. | |
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| − | + | If the -v flag is given, the file '''y.output''' is prepared, | |
| − | + | which contains a description of the parsing tables and a | |
| − | + | report on conflicts generated by ambiguities in the grammar. | |
| − | + | If the -d flag is used, the file '''y.tab.h''' is generated with the '''define''' statements that associate the '''yacc'''-assigned `token codes' with the user-declared `token names'. This allows source files other than '''y.tab.c''' to access the token codes. | |
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== FILES == | == FILES == | ||
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== SEE ALSO == | == SEE ALSO == | ||
| − | + | *[[32v 1m lex|'''lex'''(1)]] | |
| − | + | *'''LR Parsing''' by A. V. Aho and S. C. Johnson, Computing Surveys, June, 1974. | |
| − | + | *'''YACC - Yet Another Compiler Compiler''' by S. C. Johnson. | |
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== DIAGNOSTICS == | == DIAGNOSTICS == | ||
| − | + | The number of reduce-reduce and shift-reduce conflicts is | |
| − | + | reported on the standard output; a more detailed report is | |
| − | + | found in the '''y.output''' file. Similarly, if some rules are | |
| − | + | not reachable from the start symbol, this is also reported. | |
== BUGS == | == BUGS == | ||
| − | + | Because file names are fixed, at most one '''yacc''' process can be active in a given directory at a time. | |
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[[Category:32v man section 1]] | [[Category:32v man section 1]] | ||
Latest revision as of 20:34, 26 October 2009
YACC(1) UNIX Programmer's Manual YACC(1)
NAME
yacc - yet another compiler-compiler
SYNOPSIS
yacc [ -vd ] grammar
DESCRIPTION
Yacc converts a context-free grammar into a set of tables for a simple automaton which executes an LR(1) parsing algorithm. The grammar may be ambiguous; specified precedence rules are used to break ambiguities.
The output file, y.tab.c, must be compiled by the C compiler to produce a program yyparse. This program must be loaded with the lexical analyzer program, yylex, as well as main and yyerror, an error handling routine. These routines must be supplied by the user; Lex(1) is useful for creating lexical analyzers usable by yacc.
If the -v flag is given, the file y.output is prepared, which contains a description of the parsing tables and a report on conflicts generated by ambiguities in the grammar.
If the -d flag is used, the file y.tab.h is generated with the define statements that associate the yacc-assigned `token codes' with the user-declared `token names'. This allows source files other than y.tab.c to access the token codes.
FILES
y.output
y.tab.c
y.tab.h defines for token names
yacc.tmp, yacc.acts temporary files
/usr/lib/yaccpar parser prototype for C programs
/lib/liby.a library with default `main' and `yyerror'
SEE ALSO
- lex(1)
- LR Parsing by A. V. Aho and S. C. Johnson, Computing Surveys, June, 1974.
- YACC - Yet Another Compiler Compiler by S. C. Johnson.
DIAGNOSTICS
The number of reduce-reduce and shift-reduce conflicts is reported on the standard output; a more detailed report is found in the y.output file. Similarly, if some rules are not reachable from the start symbol, this is also reported.
BUGS
Because file names are fixed, at most one yacc process can be active in a given directory at a time.
