[unix-history] / usr / src / old / lex / lex.1

.\"	@(#)lex.1	6.2 (Berkeley) %G%
.\"
.TH LEX 1 ""
.AT 3
.SH NAME
lex \- generator of lexical analysis programs
.SH SYNOPSIS
.B lex
[
.B \-tvfn
] [ file ] ...
.SH DESCRIPTION
.I Lex
generates programs to be used in simple lexical analyis of text.
The input
.I files
(standard input default) contain regular expressions
to be searched for, and actions written in C to be executed when
expressions are found.
.PP
A C source program, 'lex.yy.c' is generated, to be compiled thus:
.IP
cc lex.yy.c \-ll
.LP
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.
.PP
The options have the following meanings.
.TP
.B \-t
Place the result on the standard output instead of in file "lex.yy.c".
.TP
.B \-v
Print a one-line summary of statistics of the generated analyzer.
.TP
.B \-n
Opposite of
.BR \-v ;
.B \-n
is default.
.TP
.B \-f
"Faster" compilation: don't bother to pack
the resulting tables; limited to small programs.
.SH EXAMPLE
.IP
lex lexcommands
.PP
would draw
.I lex
instructions from the file
.I lexcommands,
and place the output in
.I lex.yy.c
.IP ""
.nf
.ta \w'[A\-Z] 'u
%%
[A\-Z]	putchar(yytext[0]+\'a\'\-\'A\');
[ ]+$	;
[ ]+	putchar(\' \');
.fi
.PP
is an example of a
.I lex
program that would be put into a
.I lex
command file.  This program converts upper case to lower,
removes blanks at the end of lines,
and replaces multiple blanks by single blanks.
.SH "SEE ALSO"
yacc(1), sed(1)
.br
M. E. Lesk and E. Schmidt,
.I LEX \- Lexical Analyzer Generator
Commit	Line	Data
0d1c5a97	1	.\" @(#)lex.1 6.2 (Berkeley) %G%
74585891	2	.\"
f2db4a3c	3	.TH LEX 1 ""
74585891 KM	4	.AT 3
	5	.SH NAME
	6	lex \- generator of lexical analysis programs
	7	.SH SYNOPSIS
	8	.B lex
	9	[
	10	.B \-tvfn
	11	] [ file ] ...
	12	.SH DESCRIPTION
	13	.I Lex
	14	generates programs to be used in simple lexical analyis of text.
	15	The input
	16	.I files
c16b12ba	17	(standard input default) contain regular expressions
74585891 KM	18	to be searched for, and actions written in C to be executed when
	19	expressions are found.
	20	.PP
c16b12ba	21	A C source program, 'lex.yy.c' is generated, to be compiled thus:
74585891 KM	22	.IP
	23	cc lex.yy.c \-ll
	24	.LP
	25	This program, when run, copies unrecognized portions of
c16b12ba	26	the input to the output, and executes the associated
74585891 KM	27	C action for each regular expression that is recognized.
74585891 KM	28	.PP
74585891 KM	29	The options have the following meanings.
	30	.TP
	31	.B \-t
c16b12ba	32	Place the result on the standard output instead of in file "lex.yy.c".
74585891 KM	33	.TP
	34	.B \-v
	35	Print a one-line summary of statistics of the generated analyzer.
	36	.TP
	37	.B \-n
	38	Opposite of
	39	.BR \-v ;
	40	.B \-n
	41	is default.
	42	.TP
	43	.B \-f
c16b12ba	44	"Faster" compilation: don't bother to pack
74585891	45	the resulting tables; limited to small programs.
c16b12ba KM	46	.SH EXAMPLE
	47	.IP
	48	lex lexcommands
	49	.PP
	50	would draw
	51	.I lex
	52	instructions from the file
	53	.I lexcommands,
	54	and place the output in
	55	.I lex.yy.c
	56	.IP ""
	57	.nf
	58	.ta \w'[A\-Z] 'u
	59	%%
	60	[A\-Z] putchar(yytext[0]+\'a\'\-\'A\');
0d1c5a97	61	[ ]+$ ;
c16b12ba KM	62	[ ]+ putchar(\' \');
	63	.fi
	64	.PP
	65	is an example of a
	66	.I lex
	67	program that would be put into a
	68	.I lex
	69	command file. This program converts upper case to lower,
	70	removes blanks at the end of lines,
	71	and replaces multiple blanks by single blanks.
74585891 KM	72	.SH "SEE ALSO"
	73	yacc(1), sed(1)
	74	.br
	75	M. E. Lesk and E. Schmidt,
	76	.I LEX \- Lexical Analyzer Generator