YACC(CP) XENIX System V YACC(CP)
Name
yacc - Invokes a compiler-compiler.
Syntax
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(CP) 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
See Also
lex(CP)
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.
Notes
Because filenames are fixed, at most one yacc process can be
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YACC(CP) XENIX System V YACC(CP)
active in a given directory at a time.
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