9srv Manual Collection/plan9/lex(1) 9srv Manual Collection/plan9/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, `LEX­Lexical Analyzer Generator', Unix Research 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.

9srv Manual Collection/plan9/lex(1) Rev:  Sun Dec 02 23:42:12 GMT 2007