32v 1m lex

LEX(1) UNIX Programmer's Manual LEX(1)

NAME

    lex - generator of lexical analysis programs

SYNOPSIS

    lex [ -tvfn ] [ file ] ...

DESCRIPTION

    _L_e_x generates programs to be used in simple lexical analyis
    of text.  The input _f_i_l_e_s (standard input default) contain
    regular expressions to be searched for, and actions written
    in C to be executed when expressions are found.

    A C source program, `lex.yy.c' is generated, to be compiled
    thus:

         cc lex.yy.c -ll

    This program, when run, copies unrecognized portions of the
    input to the output, and executes the associated C action
    for each regular expression that is recognized.

    The following _l_e_x program converts upper case to lower,
    removes blanks at the end of lines, and replaces multiple
    blanks by single blanks.

         %%
         [A-Z] putchar(yytext[0]+'a'-'A');
         [ ]+$
         [ ]+  putchar(' ');

    The options have the following meanings.

    -t   Place the result on the standard output instead of in
         file `lex.yy.c'.

    -v   Print a one-line summary of statistics of the generated
         analyzer.

    -n   Opposite of -v; -n is default.

    -f   `Faster' compilation: don't bother to pack the result-
         ing tables; limited to small programs.

SEE ALSO

    yacc(1)
    M. E. Lesk and E. Schmidt, _L_E_X - _L_e_x_i_c_a_l _A_n_a_l_y_z_e_r _G_e_n_e_r_a_t_o_r