LEX(1)

NAME
lex - generator of lexical analysis programs

SYNOPSIS
lex [ -tvn9 ] [ file ... ]

DESCRIPTION
Lex generates programs to be used in simple lexical analysis of text. The input files (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. 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 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.

-9  Adds code to be able to compile through the native C compilers.

EXAMPLES
This 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(' ');

FILES

lex.yy.c
    output

/sys/lib/lex/ncform
    template

SEE ALSO
yacc(1), sed((1))
M. E. Lesk and E. Schmidt, `LEX—Lexical Analyzer Generator', Unix Research System Programmer's Manual, Tenth Edition, Volume 2.

SOURCE
/src/cmd/lex

BUGS
Cannot handle UTF.

The asteroid to kill this dinosaur is still in orbit.