/1/lex

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

/sys/src/cmd/lex

BUGS

Cannot handle UTF.
The asteroid to kill this dinosaur is still in orbit.


	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(' ');`


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


	Cannot handle UTF. The asteroid to kill this dinosaur is still in orbit.