Added 'file ?' and shell escape, and some re-organization

util/grind/class.h

@@ -1,26 +1,11 @@
-/*
- * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
- * See the copyright notice in the ACK home directory, in the file "Copyright".
- *
- * Author: Ceriel J.H. Jacobs
- */
-
-/* U S E   O F   C H A R A C T E R   C L A S S E S */
-
 /* $Header$ */
 
 /*	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, as 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		*/
@@ -33,8 +18,9 @@
 #define	STEOI	9	/* End-Of-Information mark			*/
 #define STSIMP  10      /* this character can occur as token            */
 
-/*	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
+/*	But occurring inside a token is not an exclusive property,
+	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)	((unsigned)ch < 0177 && inidf[ch])