[unix-history] / usr / man / cat1 / lex.0



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


N\bNA\bAM\bME\bE
     lex - generator of lexical analysis programs

S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
     l\ble\bex\bx [ -\b-t\btv\bvf\bfn\bn ] [ file ] ...

D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
     _\bL_\be_\bx generates programs to be used in simple lexical analyis
     of text.  The input _\bf_\bi_\bl_\be_\bs (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 options have the following meanings.

     -\b-t\bt   Place the result on the standard output instead of in
	  file "lex.yy.c".

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

     -\b-n\bn   Opposite of -\b-v\bv; -\b-n\bn is default.

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

E\bEX\bXA\bAM\bMP\bPL\bLE\bE
	  lex lexcommands

     would draw _\bl_\be_\bx instructions from the file _\bl_\be_\bx_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\bs, and
     place the output in _\bl_\be_\bx._\by_\by._\bc


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

     is an example of a _\bl_\be_\bx program that would be put into a _\bl_\be_\bx
     command file.  This program converts upper case to lower,
     removes blanks at the end of lines, and replaces multiple
     blanks by single blanks.


Printed 7/9/88		 April 14, 1986                         1


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


S\bSE\bEE\bE A\bAL\bLS\bSO\bO
     yacc(1), sed(1)
     M. E. Lesk and E. Schmidt, _\bL_\bE_\bX - _\bL_\be_\bx_\bi_\bc_\ba_\bl _\bA_\bn_\ba_\bl_\by_\bz_\be_\br _\bG_\be_\bn_\be_\br_\ba_\bt_\bo_\br


Printed 7/9/88		 April 14, 1986                         2
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	4	LEX(1) UNIX Programmer's Manual LEX(1)
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	8	N\bNA\bAM\bME\bE
	9	lex - generator of lexical analysis programs
	10
	11	S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
	12	l\ble\bex\bx [ -\b-t\btv\bvf\bfn\bn ] [ file ] ...
	13
	14	D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
	15	_\bL_\be_\bx generates programs to be used in simple lexical analyis
	16	of text. The input _\bf_\bi_\bl_\be_\bs (standard input default) contain
	17	regular expressions to be searched for, and actions written
	18	in C to be executed when expressions are found.
	19
	20	A C source program, 'lex.yy.c' is generated, to be compiled
	21	thus:
	22
	23	cc lex.yy.c -ll
	24
	25	This program, when run, copies unrecognized portions of the
	26	input to the output, and executes the associated C action
	27	for each regular expression that is recognized.
	28
	29	The options have the following meanings.
	30
	31	-\b-t\bt Place the result on the standard output instead of in
	32	file "lex.yy.c".
	33
	34	-\b-v\bv Print a one-line summary of statistics of the generated
	35	analyzer.
	36
	37	-\b-n\bn Opposite of -\b-v\bv; -\b-n\bn is default.
	38
	39	-\b-f\bf "Faster" compilation: don't bother to pack the result-
	40	ing tables; limited to small programs.
	41
	42	E\bEX\bXA\bAM\bMP\bPL\bLE\bE
	43	lex lexcommands
	44
	45	would draw _\bl_\be_\bx instructions from the file _\bl_\be_\bx_\bc_\bo_\bm_\bm_\ba_\bn_\bd_\bs, and
	46	place the output in _\bl_\be_\bx._\by_\by._\bc
	47
	48
	49	%%
	50	[A-Z] putchar(yytext[0]+'a'-'A');
	51	[ ]+$ ;
	52	[ ]+ putchar(' ');
	53
	54	is an example of a _\bl_\be_\bx program that would be put into a _\bl_\be_\bx
	55	command file. This program converts upper case to lower,
	56	removes blanks at the end of lines, and replaces multiple
	57	blanks by single blanks.
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	63	Printed 7/9/88 April 14, 1986 1
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70	LEX(1) UNIX Programmer's Manual LEX(1)
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74	S\bSE\bEE\bE A\bAL\bLS\bSO\bO
75	yacc(1), sed(1)
76	M. E. Lesk and E. Schmidt, _\bL_\bE_\bX - _\bL_\be_\bx_\bi_\bc_\ba_\bl _\bA_\bn_\ba_\bl_\by_\bz_\be_\br _\bG_\be_\bn_\be_\br_\ba_\bt_\bo_\br
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