term% cat index.txt LEX(1) General Commands Manual 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 expres‐
sions 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 ana‐
lyzer.
-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 Re‐
search System Programmer's Manual, Tenth Edition, Volume 2.
SOURCE
/sys/src/cmd/lex
BUGS
Cannot handle UTF.
The asteroid to kill this dinosaur is still in orbit.
LEX(1)