YACC(1)                                                                YACC(1)



NAME
       yacc - yet another compiler-compiler

SYNOPSIS
       yacc [ -vd ] grammar

DESCRIPTION
       _Y_a_c_c  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_._t_a_b_._c, must be compiled by the C compiler to produce
       a  program  _y_y_p_a_r_s_e.  This program must be loaded with the lexical ana‐
       lyzer program, _y_y_l_e_x, as well as _m_a_i_n and _y_y_e_r_r_o_r,  an  error  handling
       routine.  These routines must be supplied by the user; _L_e_x(1) is useful
       for creating lexical analyzers usable by _y_a_c_c.

       If the -v flag is given, the file _y_._o_u_t_p_u_t 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_._t_a_b_._h is generated with  the  _d_e_f_i_n_e
       statements  that  associate  the  _y_a_c_c-assigned  ‘token codes’ with the
       user-declared ‘token names’.   This  allows  source  files  other  than
       _y_._t_a_b_._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
       _l_e_x(1)
       _L_R  _P_a_r_s_i_n_g  by  A.  V. Aho and S. C. Johnson, Computing Surveys, June,
       1974.
       _Y_A_C_C _- _Y_e_t _A_n_o_t_h_e_r _C_o_m_p_i_l_e_r _C_o_m_p_i_l_e_r 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_._o_u_t_p_u_t
       file.  Similarly, if some rules are not reachable from the  start  sym‐
       bol, this is also reported.

BUGS
       Because file names are fixed, at most one _y_a_c_c process can be active in
       a given directory at a time.



7th Edition                     April 29, 1985                         YACC(1)