YACC(1) — USER COMMANDS
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 function named yyparse. The yyparse function must be loaded with the lexical analyzer 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-produced parsers.
OPTIONS
−v Prepare the file y.output containing a description of the parsing tables and a report on conflicts generated by ambiguities in the grammar.
−d Generate the file y.tab.h with the define statements that associate the yacc-assigned ‘token codes’ with the user-declared ‘token names’ so that source files other than y.tab.c can access the token codes.
FILES
y.outputdescription of parsing tables and conflict report
y.tab.coutput parser
y.tab.hdefines for token names
yacc.tmp, yacc.actstemporary files
/usr/lib/yaccparparser prototype for C programs
SEE ALSO
LR Parsing by A. V. Aho and S. C. Johnson, Computing Surveys, June, 1974
Yacc — Yet Another Compiler Compiler in Programming Utilities for the Sun Workstation
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 should be active in a given directory at a time.
Sun Release 3.2 — Last change: 8 October 1984