fixes

著名Awk语言的编译器

	s/aprintf/awkprint, s/asprintf/awksprintf/ to avoid some name clashes
	with unwisely-written header files.

	thanks to jeffrey friedl for several of these.

May 26, 1996:
	an attempt to rationalize the (unsigned) char issue.  almost all
	instances of unsigned char have been removed; the handful of places
	in b.c where chars are used as table indices have been hand-crafted.
	added some latin-1 tests to the regression, but i'm not confident;
	none of my compilers seem to care much.  thanks to nelson beebe for
	pointing out some others that do care.

May 2, 1996:
	removed all register declarations.

	enhanced split(), as in gawk, etc:  split(s, a, "") splits s into
	a[1]...a[length(s)] with each character a single element.

	made the same changes for field-splitting if FS is "".

	added nextfile, as in gawk: causes immediate advance to next
	input file. (thanks to arnold robbins for inspiration and code).

	small fixes to regexpr code:  can now handle []], [[], and
	variants;  [] is now a syntax error, rather than matching 
	everything;  [z-a] is now empty, not z.  far from complete
	or correct, however.  (thanks to jeffrey friedl for pointing out
	some awful behaviors.)

Apr 29, 1996:
	replaced uchar by uschar everwhere; apparently some compilers
	usurp this name and this causes conflicts.

	fixed call to time in run.c (bltin); arg is time_t *.

	replaced horrible pointer/long punning in b.c by a legitimate
	union.  should be safer on 64-bit machines and cleaner everywhere.
	(thanks to nelson beebe for pointing out some of these problems.)

	replaced nested comments by #if 0...#endif in run.c, lib.c.

	removed getsval, setsval, execute macros from run.c and lib.c.
	machines are 100x faster than they were when these macros were
	first used.

	revised filenames: awk.g.y => awkgram.y, awk.lx.l => awklex.l,
	y.tab.[ch] => ytab.[ch], lex.yy.c => lexyy.c, all in the aid of
	portability to nameless systems.

	"make bundle" now includes yacc and lex output files for recipients
	who don't have yacc or lex.

Aug 15, 1995:
	initialized Cells in setsymtab more carefully; some fields
	were not set.  (thanks to purify, all of whose complaints i
	think i now understand.)

	fixed at least one error in gsub that looked at -1-th element
	of an array when substituting for a null match (e.g., $).

	delete arrayname is now legal; it clears the elements but leaves
	the array, which may not be the right behavior.

	modified makefile: my current make can't cope with the test used
	to avoid unnecessary yacc invocations.

Jul 17, 1995:
	added dynamically growing strings to awk.lx.l and b.c
	to permit regular expressions to be much bigger.
	the state arrays can still overflow.

Aug 24, 1994:
	detect duplicate arguments in function definitions (mdm).

May 11, 1994:
	trivial fix to printf to limit string size in sub().

Apr 22, 1994:
	fixed yet another subtle self-assignment problem:
	$1 = $2; $1 = $1 clobbered $1.

	Regression tests now use private echo, to avoid quoting problems.

Feb 2, 1994:
	changed error() to print line number as %d, not %g.

Jul 23, 1993:
	cosmetic changes: increased sizes of some arrays,
	reworded some error messages.

	added CONVFMT as in posix (just replaced OFMT in getsval)

	FILENAME is now "" until the first thing that causes a file
	to be opened.

Nov 28, 1992:
	deleted yyunput and yyoutput from proto.h;
	different versions of lex give these different declarations.

May 31, 1992:
	added -mr N and -mf N options: more record and fields.
	these really ought to adjust automatically.

	cleaned up some error messages; "out of space" now means
	malloc returned NULL in all cases.

	changed rehash so that if it runs out, it just returns;
	things will continue to run slow, but maybe a bit longer.

Apr 24, 1992:
	remove redundant close of stdin when using -f -.

	got rid of core dump with -d; awk -d just prints date.

Apr 12, 1992:
	added explicit check for /dev/std(in,out,err) in redirection.
	unlike gawk, no /dev/fd/n yet.

	added (file/pipe) builtin.  hard to test satisfactorily.
	not posix.

Feb 20, 1992:
	recompile after abortive changes;  should be unchanged.

Dec 2, 1991:
	die-casting time:  converted to ansi C, installed that.

Nov 30, 1991:
	fixed storage leak in freefa, failing to recover [N]CCL.
	thanks to Bill Jones ([e-mail])

Nov 19, 1991:
	use RAND_MAX instead of literal in builtin().

Nov 12, 1991:
	cranked up some fixed-size arrays in b.c, and added a test for
	overflow in penter.  thanks to mark larsen.

Sep 24, 1991:
	increased buffer in gsub.  a very crude fix to a general problem.
	and again on Sep 26.

Aug 18, 1991:
	enforce variable name syntax for commandline variables: has to
	start with letter or _.

Jul 27, 1991:
	allow newline after ; in for statements.

Jul 21, 1991:
	fixed so that in self-assignment like $1=$1, side effects
	like recomputing $0 take place.  (this is getting subtle.)

Jun 30, 1991:
	better test for detecting too-long output record.

Jun 2, 1991:
	better defense against very long printf strings.
	made break and continue illegal outside of loops.

May 13, 1991:
	removed extra arg on gettemp, tempfree.  minor error message rewording.

May 6, 1991:
	fixed silly bug in hex parsing in hexstr().
	removed an apparently unnecessary test in isnumber().
	warn about weird printf conversions.
	fixed unchecked array overwrite in relex().

	changed for (i in array) to access elements in sorted order.
	then unchanged it -- it really does run slower in too many cases.
	left the code in place, commented out.

Feb 10, 1991:
	check error status on all writes, to avoid banging on full disks.

Jan 28, 1991:
	awk -f - reads the program from stdin.

Jan 11, 1991:
	failed to set numeric state on $0 in cmd|getline context in run.c.

Nov 2, 1990:
	fixed sleazy test for integrality in getsval;  use modf.

Oct 29, 1990:
	fixed sleazy buggy code in lib.c that looked (incorrectly) for
	too long input lines.

Oct 14, 1990:
	fixed the bug on p. 198 in which it couldn't deduce that an
	argument was an array in some contexts.  replaced the error
	message in intest() by code that damn well makes it an array.

Oct 8, 1990:
	fixed horrible bug:  types and values were not preserved in
	some kinds of self-assignment. (in assign().)

Aug 24, 1990:
	changed NCHARS to 256 to handle 8-bit characters in strings
	presented to match(), etc.

Jun 26, 1990:
	changed struct rrow (awk.h) to use long instead of int for lval,
	since cfoll() stores a pointer in it.  now works better when int's
	are smaller than pointers!

May 6, 1990:
	AVA fixed the grammar so that ! is uniformly of the same precedence as
	unary + and -.  This renders illegal some constructs like !x=y, which
	now has to be parenthesized as !(x=y), and makes others work properly:
	!x+y is (!x)+y, and x!y is x !y, not two pattern-action statements.
	(These problems were pointed out by Bob Lenk of Posix.)

	Added \x to regular expressions (already in strings).
	Limited octal to octal digits; \8 and \9 are not octal.
	Centralized the code for parsing escapes in regular expressions.
	Added a bunch of tests to T.re and T.sub to verify some of this.

Feb 9, 1990:
	fixed null pointer dereference bug in main.c:  -F[nothing].  sigh.

	restored srand behavior:  it returns the current seed.

Jan 18, 1990:
	srand now returns previous seed value (0 to start).

Jan 5, 1990:
	fix potential problem in tran.c -- something was freed,
	then used in freesymtab.

Oct 18, 1989:
	another try to get the max number of open files set with
	relatively machine-independent code.

	small fix to input() in case of multiple reads after EOF.

Oct 11, 1989:
	FILENAME is now defined in the BEGIN block -- too many old
	programs broke.

	"-" means stdin in getline as well as on the commandline.

	added a bunch of casts to the code to tell the truth about
	char * vs. unsigned char *, a right royal pain.  added a
	setlocale call to the front of main, though probably no one
	has it usefully implemented yet.

Aug 24, 1989:
	removed redundant relational tests against nullnode if parse
	tree already had a relational at that point.

Aug 11, 1989:
	fixed bug:  commandline variable assignment has to look like
	var=something.  (consider the man page for =, in file =.1)

	changed number of arguments to functions to static arrays
	to avoid repeated malloc calls.

Aug 2, 1989:
	restored -F (space) separator

Jul 30, 1989:
	added -v x=1 y=2 ... for immediate commandline variable assignment;
	done before the BEGIN block for sure.  they have to precede the
	program if the program is on the commandline.
	Modified Aug 2 to require a separate -v for each assignment.

Jul 10, 1989:
	fixed ref-thru-zero bug in environment code in tran.c

Jun 23, 1989:
	add newline to usage message.

Jun 14, 1989:
	added some missing ansi printf conversion letters: %i %X %E %G.
	no sensible meaning for h or L, so they may not do what one expects.

	made %* conversions work.

	changed x^y so that if n is a positive integer, it's done
	by explicit multiplication, thus achieving maximum accuracy.
	(this should be done by pow() but it seems not to be locally.)
	done to x ^= y as well.

Jun 4, 1989:
	ENVIRON array contains environment: if shell variable V=thing,
		ENVIRON["V"] is "thing"

	multiple -f arguments permitted.  error reporting is naive.
	(they were permitted before, but only the last was used.)

	fixed a really stupid botch in the debugging macro dprintf

	fixed order of evaluation of commandline assignments to match
	what the book claims:  an argument of the form x=e is evaluated
	at the time it would have been opened if it were a filename (p 63).
	this invalidates the suggested answer to ex 4-1 (p 195).

	removed some code that permitted -F (space) fieldseparator,
	since it didn't quite work right anyway.  (restored aug 2)

Apr 27, 1989:
	Line number now accumulated correctly for comment lines.

Apr 26, 1989:
	Debugging output now includes a version date,
	if one compiles it into the source each time.

Apr 9, 1989:
	Changed grammar to prohibit constants as 3rd arg of sub and gsub;
	prevents class of overwriting-a-constant errors.  (Last one?)
	This invalidates the "banana" example on page 43 of the book.

	Added \a ("alert"), \v (vertical tab), \xhhh (hexadecimal),
	as in ANSI, for strings.  Rescinded the sloppiness that permitted
	non-octal digits in \ooo.  Warning:  not all compilers and libraries
	will be able to deal with \x correctly.

Jan 9, 1989:
	Fixed bug that caused tempcell list to contain a duplicate.
	The fix is kludgy.

Dec 17, 1988:
	Catches some more commandline errors in main.
	Removed redundant decl of modf in run.c (confuses some compilers).
	Warning:  there's no single declaration of malloc, etc., in awk.h
	that seems to satisfy all compilers.

Dec 7, 1988:
	Added a bit of code to error printing to avoid printing nulls.
	(Not clear that it actually would.)

Nov 27, 1988:
	With fear and trembling, modified the grammar to permit
	multiple pattern-action statements on one line without
	an explicit separator.  By definition, this capitulation
	to the ghost of ancient implementations remains undefined
	and thus subject to change without notice or apology.
	DO NOT COUNT ON IT.

Oct 30, 1988:
	Fixed bug in call() that failed to recover storage.

	A warning is now generated if there are more arguments
	in the call than in the definition (in lieu of fixing
	another storage leak).

Oct 20, 1988:
	Fixed %c:  if expr is numeric, use numeric value;
	otherwise print 1st char of string value.  still
	doesn't work if the value is 0 -- won't print \0.

	Added a few more checks for running out of malloc.

Oct 12, 1988:
	Fixed bug in call() that freed local arrays twice.

	Fixed to handle deletion of non-existent array right;
	complains about attempt to delete non-array element.

Sep 30, 1988:
	Now guarantees to evaluate all arguments of built-in
	functions, as in C;  the appearance is that arguments
	are evaluated before the function is called.  Places
	affected are sub (gsub was ok), substr, printf, and
	all the built-in arithmetic functions in bltin().
	A warning is generated if a bltin() is called with
	the wrong number of arguments.

	This requires changing makeprof on p167 of the book.

Aug 23, 1988:
	setting FILENAME in BEGIN caused core dump, apparently
	because it was freeing space not allocated by malloc.

July 24, 1988:
	fixed egregious error in toupper/tolower functions.
	still subject to rescinding, however.

July 2, 1988:
	flush stdout before opening file or pipe

July 2, 1988:
	performance bug in b.c/cgoto(): not freeing some sets of states.
	partial fix only right now, and the number of states increased
	to make it less obvious.

June 1, 1988:
	check error status on close

May 28, 1988:
	srand returns seed value it's using.
	see 1/18/90

May 22, 1988:
	Removed limit on depth of function calls.

May 10, 1988:
	Fixed lib.c to permit _ in commandline variable names.

Mar 25, 1988:
	main.c fixed to recognize -- as terminator of command-
	line options.  Illegal options flagged.
	Error reporting slightly cleaned up.

Dec 2, 1987:
	Newer C compilers apply a strict scope rule to extern
	declarations within functions.  Two extern declarations in
	lib.c and tran.c have been moved to obviate this problem.

Oct xx, 1987:
	Reluctantly added toupper and tolower functions.
	Subject to rescinding without notice.

Sep 17, 1987:
	Error-message printer had printf(s) instead of
	printf("%s",s);  got core dumps when the message
	included a %.

Sep 12, 1987:
	Very long printf strings caused core dump;
	fixed aprintf, asprintf, format to catch them.
	Can still get a core dump in printf itself.