41 lines
1.5 KiB
C
41 lines
1.5 KiB
C
/*
|
|
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
|
*/
|
|
/* $Id$ */
|
|
/* U S E O F C H A R A C T E R C L A S S E S */
|
|
|
|
/* As a starter, chars are divided into classes, according to which
|
|
token they can be the start of.
|
|
At present such a class number is supposed to fit in 4 bits.
|
|
*/
|
|
|
|
#define class(ch) (tkclass[ch])
|
|
|
|
/* Being the start of a token is, fortunately, a mutual exclusive
|
|
property, so, although there are less than 16 classes they can be
|
|
packed in 4 bits.
|
|
*/
|
|
|
|
#define STSKIP 0 /* spaces and so on: skipped characters */
|
|
#define STNL 1 /* newline character(s): update linenumber etc. */
|
|
#define STGARB 2 /* garbage ascii character: not allowed in C */
|
|
#define STSIMP 3 /* this character can occur as token in C */
|
|
#define STCOMP 4 /* this one can start a compound token in C */
|
|
#define STIDF 5 /* being the initial character of an identifier */
|
|
#define STCHAR 6 /* the starter of a character constant */
|
|
#define STSTR 7 /* the starter of a string */
|
|
#define STNUM 8 /* the starter of a numeric constant */
|
|
#define STEOI 9 /* End-Of-Information mark */
|
|
|
|
/* But occurring inside a token is not, so we need 1 bit for each
|
|
class. This is implemented as a collection of tables to speed up
|
|
the decision whether a character has a special meaning.
|
|
*/
|
|
#define in_idf(ch) (inidf[ch])
|
|
#define is_oct(ch) (isoct[ch])
|
|
#define is_dig(ch) (isdig[ch])
|
|
#define is_hex(ch) (ishex[ch])
|
|
|
|
extern char tkclass[];
|
|
extern char inidf[], isoct[], isdig[], ishex[];
|