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+Changes between release 2.5.4 (11Sep96) and release 2.5.3:
+
+ - Fixed a bug introduced in 2.5.3 that blew it when a call
+ to input() occurred at the end of an input file.
+
+ - Fixed scanner skeleton so the example in the man page of
+ scanning strings using exclusive start conditions works.
+
+ - Minor Makefile tweaks.
+
+
+Changes between release 2.5.3 (29May96) and release 2.5.2:
+
+ - Some serious bugs in yymore() have been fixed. In particular,
+ when using AT&T-lex-compatibility or %array, you can intermix
+ calls to input(), unput(), and yymore(). (This still doesn't
+ work for %pointer, and isn't likely to in the future.)
+
+ - A bug in handling NUL's in the input stream of scanners using
+ REJECT has been fixed.
+
+ - The default main() in libfl.a now repeatedly calls yylex() until
+ it returns 0, rather than just calling it once.
+
+ - Minor tweak for Windows NT Makefile, MISC/NT/Makefile.
+
+
+Changes between release 2.5.2 (25Apr95) and release 2.5.1:
+
+ - The --prefix configuration option now works.
+
+ - A bug that completely broke the "-Cf" table compression
+ option has been fixed.
+
+ - A major headache involving "const" declarators and Solaris
+ systems has been fixed.
+
+ - An octal escape sequence in a flex regular expression must
+ now contain only the digits 0-7.
+
+ - You can now use "--" on the flex command line to mark the
+ end of flex options.
+
+ - You can now specify the filename '-' as a synonym for stdin.
+
+ - By default, the scanners generated by flex no longer
+ statically initialize yyin and yyout to stdin and stdout.
+ This change is necessary because in some ANSI environments,
+ stdin and stdout are not compile-time constant. You can
+ force the initialization using "%option stdinit" in the first
+ section of your flex input.
+
+ - "%option nounput" now correctly omits the unput() routine
+ from the output.
+
+ - "make clean" now removes config.log, config.cache, and the
+ flex binary. The fact that it removes the flex binary means
+ you should take care if making changes to scan.l, to make
+ sure you don't wind up in a bootstrap problem.
+
+ - In general, the Makefile has been reworked somewhat (thanks
+ to Francois Pinard) for added flexibility - more changes will
+ follow in subsequent releases.
+
+ - The .texi and .info files in MISC/texinfo/ have been updated,
+ thanks also to Francois Pinard.
+
+ - The FlexLexer::yylex(istream* new_in, ostream* new_out) method
+ now does not have a default for the first argument, to disambiguate
+ it from FlexLexer::yylex().
+
+ - A bug in destructing a FlexLexer object before doing any scanning
+ with it has been fixed.
+
+ - A problem with including FlexLexer.h multiple times has been fixed.
+
+ - The alloca() chud necessary to accommodate bison has grown
+ even uglier, but hopefully more correct.
+
+ - A portability tweak has been added to accommodate compilers that
+ use char* generic pointers.
+
+ - EBCDIC contact information in the file MISC/EBCDIC has been updated.
+
+ - An OS/2 Makefile and config.h for flex 2.5 is now available in
+ MISC/OS2/, contributed by Kai Uwe Rommel.
+
+ - The descrip.mms file for building flex under VMS has been updated,
+ thanks to Pat Rankin.
+
+ - The notes on building flex for the Amiga have been updated for
+ flex 2.5, contributed by Andreas Scherer.
+
+
+Changes between release 2.5.1 (28Mar95) and release 2.4.7:
+
+ - A new concept of "start condition" scope has been introduced.
+ A start condition scope is begun with:
+
+ <SCs>{
+
+ where SCs is a list of one or more start conditions. Inside
+ the start condition scope, every rule automatically has the
+ prefix <SCs> applied to it, until a '}' which matches the
+ initial '{'. So, for example:
+
+ <ESC>{
+ "\\n" return '\n';
+ "\\r" return '\r';
+ "\\f" return '\f';
+ "\\0" return '\0';
+ }
+
+ is equivalent to:
+
+ <ESC>"\\n" return '\n';
+ <ESC>"\\r" return '\r';
+ <ESC>"\\f" return '\f';
+ <ESC>"\\0" return '\0';
+
+ As indicated in this example, rules inside start condition scopes
+ (and any rule, actually, other than the first) can be indented,
+ to better show the extent of the scope.
+
+ Start condition scopes may be nested.
+
+ - The new %option directive can be used in the first section of
+ a flex scanner to control scanner-generation options. Most
+ options are given simply as names, optionally preceded by the
+ word "no" (with no intervening whitespace) to negate their
+ meaning. Some are equivalent to flex flags, so putting them
+ in your scanner source is equivalent to always specifying
+ the flag (%option's take precedence over flags):
+
+ 7bit -7 option
+ 8bit -8 option
+ align -Ca option
+ backup -b option
+ batch -B option
+ c++ -+ option
+ caseful opposite of -i option (caseful is the default);
+ case-sensitive same as above
+ caseless -i option;
+ case-insensitive same as above
+ debug -d option
+ default opposite of -s option
+ ecs -Ce option
+ fast -F option
+ full -f option
+ interactive -I option
+ lex-compat -l option
+ meta-ecs -Cm option
+ perf-report -p option
+ read -Cr option
+ stdout -t option
+ verbose -v option
+ warn opposite of -w option (so use "%option nowarn" for -w)
+
+ array equivalent to "%array"
+ pointer equivalent to "%pointer" (default)
+
+ Some provide new features:
+
+ always-interactive generate a scanner which always
+ considers its input "interactive" (no call to isatty()
+ will be made when the scanner runs)
+ main supply a main program for the scanner, which
+ simply calls yylex(). Implies %option noyywrap.
+ never-interactive generate a scanner which never
+ considers its input "interactive" (no call to isatty()
+ will be made when the scanner runs)
+ stack if set, enable start condition stacks (see below)
+ stdinit if unset ("%option nostdinit"), initialize yyin
+ and yyout statically to nil FILE* pointers, instead
+ of stdin and stdout
+ yylineno if set, keep track of the current line
+ number in global yylineno (this option is expensive
+ in terms of performance). The line number is available
+ to C++ scanning objects via the new member function
+ lineno().
+ yywrap if unset ("%option noyywrap"), scanner does not
+ call yywrap() upon EOF but simply assumes there
+ are no more files to scan
+
+ Flex scans your rule actions to determine whether you use the
+ REJECT or yymore features (this is not new). Two %options can be
+ used to override its decision, either by setting them to indicate
+ the feature is indeed used, or unsetting them to indicate it
+ actually is not used:
+
+ reject
+ yymore
+
+ Three %option's take string-delimited values, offset with '=':
+
+ outfile="<name>" equivalent to -o<name>
+ prefix="<name>" equivalent to -P<name>
+ yyclass="<name>" set the name of the C++ scanning class
+ (see below)
+
+ A number of %option's are available for lint purists who
+ want to suppress the appearance of unneeded routines in
+ the generated scanner. Each of the following, if unset,
+ results in the corresponding routine not appearing in the
+ generated scanner:
+
+ input, unput
+ yy_push_state, yy_pop_state, yy_top_state
+ yy_scan_buffer, yy_scan_bytes, yy_scan_string
+
+ You can specify multiple options with a single %option directive,
+ and multiple directives in the first section of your flex input file.
+
+ - The new function:
+
+ YY_BUFFER_STATE yy_scan_string( const char *str )
+
+ returns a YY_BUFFER_STATE (which also becomes the current input
+ buffer) for scanning the given string, which occurs starting
+ with the next call to yylex(). The string must be NUL-terminated.
+ A related function:
+
+ YY_BUFFER_STATE yy_scan_bytes( const char *bytes, int len )
+
+ creates a buffer for scanning "len" bytes (including possibly NUL's)
+ starting at location "bytes".
+
+ Note that both of these functions create and scan a *copy* of
+ the string/bytes. (This may be desirable, since yylex() modifies
+ the contents of the buffer it is scanning.) You can avoid the
+ copy by using:
+
+ YY_BUFFER_STATE yy_scan_buffer( char *base, yy_size_t size )
+
+ which scans in place the buffer starting at "base", consisting
+ of "size" bytes, the last two bytes of which *must* be
+ YY_END_OF_BUFFER_CHAR (these bytes are not scanned; thus, scanning
+ consists of base[0] through base[size-2], inclusive). If you
+ fail to set up "base" in this manner, yy_scan_buffer returns a
+ nil pointer instead of creating a new input buffer.
+
+ The type yy_size_t is an integral type to which you can cast
+ an integer expression reflecting the size of the buffer.
+
+ - Three new routines are available for manipulating stacks of
+ start conditions:
+
+ void yy_push_state( int new_state )
+
+ pushes the current start condition onto the top of the stack
+ and BEGIN's "new_state" (recall that start condition names are
+ also integers).
+
+ void yy_pop_state()
+
+ pops the top of the stack and BEGIN's to it, and
+
+ int yy_top_state()
+
+ returns the top of the stack without altering the stack's
+ contents.
+
+ The start condition stack grows dynamically and so has no built-in
+ size limitation. If memory is exhausted, program execution
+ is aborted.
+
+ To use start condition stacks, your scanner must include
+ a "%option stack" directive.
+
+ - flex now supports POSIX character class expressions. These
+ are expressions enclosed inside "[:" and ":]" delimiters (which
+ themselves must appear between the '[' and ']' of a character
+ class; other elements may occur inside the character class, too).
+ The expressions flex recognizes are:
+
+ [:alnum:] [:alpha:] [:blank:] [:cntrl:] [:digit:] [:graph:]
+ [:lower:] [:print:] [:punct:] [:space:] [:upper:] [:xdigit:]
+
+ These expressions all designate a set of characters equivalent to
+ the corresponding isXXX function (for example, [:alnum:] designates
+ those characters for which isalnum() returns true - i.e., any
+ alphabetic or numeric). Some systems don't provide isblank(),
+ so flex defines [:blank:] as a blank or a tab.
+
+ For example, the following character classes are all equivalent:
+
+ [[:alnum:]]
+ [[:alpha:][:digit:]
+ [[:alpha:]0-9]
+ [a-zA-Z0-9]
+
+ If your scanner is case-insensitive (-i flag), then [:upper:]
+ and [:lower:] are equivalent to [:alpha:].
+
+ - The promised rewrite of the C++ FlexLexer class has not yet
+ been done. Support for FlexLexer is limited at the moment to
+ fixing show-stopper bugs, so, for example, the new functions
+ yy_scan_string() & friends are not available to FlexLexer
+ objects.
+
+ - The new macro
+
+ yy_set_interactive(is_interactive)
+
+ can be used to control whether the current buffer is considered
+ "interactive". An interactive buffer is processed more slowly,
+ but must be used when the scanner's input source is indeed
+ interactive to avoid problems due to waiting to fill buffers
+ (see the discussion of the -I flag in flex.1). A non-zero value
+ in the macro invocation marks the buffer as interactive, a zero
+ value as non-interactive. Note that use of this macro overrides
+ "%option always-interactive" or "%option never-interactive".
+
+ yy_set_interactive() must be invoked prior to beginning to
+ scan the buffer.
+
+ - The new macro
+
+ yy_set_bol(at_bol)
+
+ can be used to control whether the current buffer's scanning
+ context for the next token match is done as though at the
+ beginning of a line (non-zero macro argument; makes '^' anchored
+ rules active) or not at the beginning of a line (zero argument,
+ '^' rules inactive).
+
+ - Related to this change, the mechanism for determining when a scan is
+ starting at the beginning of a line has changed. It used to be
+ that '^' was active iff the character prior to that at which the
+ scan started was a newline. The mechanism now is that '^' is
+ active iff the last token ended in a newline (or the last call to
+ input() returned a newline). For most users, the difference in
+ mechanisms is negligible. Where it will make a difference,
+ however, is if unput() or yyless() is used to alter the input
+ stream. When in doubt, use yy_set_bol().
+
+ - The new beginning-of-line mechanism involved changing some fairly
+ twisted code, so it may have introduced bugs - beware ...
+
+ - The macro YY_AT_BOL() returns true if the next token scanned from
+ the current buffer will have '^' rules active, false otherwise.
+
+ - The new function
+
+ void yy_flush_buffer( struct yy_buffer_state* b )
+
+ flushes the contents of the current buffer (i.e., next time
+ the scanner attempts to match a token using b as the current
+ buffer, it will begin by invoking YY_INPUT to fill the buffer).
+ This routine is also available to C++ scanners (unlike some
+ of the other new routines).
+
+ The related macro
+
+ YY_FLUSH_BUFFER
+
+ flushes the contents of the current buffer.
+
+ - A new "-ooutput" option writes the generated scanner to "output".
+ If used with -t, the scanner is still written to stdout, but
+ its internal #line directives (see previous item) use "output".
+
+ - Flex now generates #line directives relating the code it
+ produces to the output file; this means that error messages
+ in the flex-generated code should be correctly pinpointed.
+
+ - When generating #line directives, filenames with embedded '\'s
+ have those characters escaped (i.e., turned into '\\'). This
+ feature helps with reporting filenames for some MS-DOS and OS/2
+ systems.
+
+ - The FlexLexer class includes two new public member functions:
+
+ virtual void switch_streams( istream* new_in = 0,
+ ostream* new_out = 0 )
+
+ reassigns yyin to new_in (if non-nil) and yyout to new_out
+ (ditto), deleting the previous input buffer if yyin is
+ reassigned. It is used by:
+
+ int yylex( istream* new_in = 0, ostream* new_out = 0 )
+
+ which first calls switch_streams() and then returns the value
+ of calling yylex().
+
+ - C++ scanners now have yy_flex_debug as a member variable of
+ FlexLexer rather than a global, and member functions for testing
+ and setting it.
+
+ - When generating a C++ scanning class, you can now use
+
+ %option yyclass="foo"
+
+ to inform flex that you have derived "foo" as a subclass of
+ yyFlexLexer, so flex will place your actions in the member
+ function foo::yylex() instead of yyFlexLexer::yylex(). It also
+ generates a yyFlexLexer::yylex() member function that generates a
+ run-time error if called (by invoking yyFlexLexer::LexerError()).
+ This feature is necessary if your subclass "foo" introduces some
+ additional member functions or variables that you need to access
+ from yylex().
+
+ - Current texinfo files in MISC/texinfo, contributed by Francois
+ Pinard.
+
+ - You can now change the name "flex" to something else (e.g., "lex")
+ by redefining $(FLEX) in the Makefile.
+
+ - Two bugs (one serious) that could cause "bigcheck" to fail have
+ been fixed.
+
+ - A number of portability/configuration changes have been made
+ for easier portability.
+
+ - You can use "YYSTATE" in your scanner as an alias for YY_START
+ (for AT&T lex compatibility).
+
+ - input() now maintains yylineno.
+
+ - input() no longer trashes yytext.
+
+ - interactive scanners now read characters in YY_INPUT up to a
+ newline, a large performance gain.
+
+ - C++ scanner objects now work with the -P option. You include
+ <FlexLexer.h> once per scanner - see comments in <FlexLexer.h>
+ (or flex.1) for details.
+
+ - C++ FlexLexer objects now use the "cerr" stream to report -d output
+ instead of stdio.
+
+ - The -c flag now has its full glorious POSIX interpretation (do
+ nothing), rather than being interpreted as an old-style -C flag.
+
+ - Scanners generated by flex now include two #define's giving
+ the major and minor version numbers (YY_FLEX_MAJOR_VERSION,
+ YY_FLEX_MINOR_VERSION). These can then be tested to see
+ whether certain flex features are available.
+
+ - Scanners generated using -l lex compatibility now have the symbol
+ YY_FLEX_LEX_COMPAT #define'd.
+
+ - When initializing (i.e., yy_init is non-zero on entry to yylex()),
+ generated scanners now set yy_init to zero before executing
+ YY_USER_INIT. This means that you can set yy_init back to a
+ non-zero value in YY_USER_INIT if you need the scanner to be
+ reinitialized on the next call.
+
+ - You can now use "#line" directives in the first section of your
+ scanner specification.
+
+ - When generating full-table scanners (-Cf), flex now puts braces
+ around each row of the 2-d array initialization, to silence warnings
+ on over-zealous compilers.
+
+ - Improved support for MS-DOS. The flex sources have been successfully
+ built, unmodified, for Borland 4.02 (all that's required is a
+ Borland Makefile and config.h file, which are supplied in
+ MISC/Borland - contributed by Terrence O Kane).
+
+ - Improved support for Macintosh using Think C - the sources should
+ build for this platform "out of the box". Contributed by Scott
+ Hofmann.
+
+ - Improved support for VMS, in MISC/VMS/, contributed by Pat Rankin.
+
+ - Support for the Amiga, in MISC/Amiga/, contributed by Andreas
+ Scherer. Note that the contributed files were developed for
+ flex 2.4 and have not been tested with flex 2.5.
+
+ - Some notes on support for the NeXT, in MISC/NeXT, contributed
+ by Raf Schietekat.
+
+ - The MISC/ directory now includes a preformatted version of flex.1
+ in flex.man, and pre-yacc'd versions of parse.y in parse.{c,h}.
+
+ - The flex.1 and flexdoc.1 manual pages have been merged. There
+ is now just one document, flex.1, which includes an overview
+ at the beginning to help you find the section you need.
+
+ - Documentation now clarifies that start conditions persist across
+ switches to new input files or different input buffers. If you
+ want to e.g., return to INITIAL, you must explicitly do so.
+
+ - The "Performance Considerations" section of the manual has been
+ updated.
+
+ - Documented the "yy_act" variable, which when YY_USER_ACTION is
+ invoked holds the number of the matched rule, and added an
+ example of using yy_act to profile how often each rule is matched.
+
+ - Added YY_NUM_RULES, a definition that gives the total number
+ of rules in the file, including the default rule (even if you
+ use -s).
+
+ - Documentation now clarifies that you can pass a nil FILE* pointer
+ to yy_create_buffer() or yyrestart() if you've arrange YY_INPUT
+ to not need yyin.
+
+ - Documentation now clarifies that YY_BUFFER_STATE is a pointer to
+ an opaque "struct yy_buffer_state".
+
+ - Documentation now stresses that you gain the benefits of removing
+ backing-up states only if you remove *all* of them.
+
+ - Documentation now points out that traditional lex allows you
+ to put the action on a separate line from the rule pattern if
+ the pattern has trailing whitespace (ugh!), but flex doesn't
+ support this.
+
+ - A broken example in documentation of the difference between
+ inclusive and exclusive start conditions is now fixed.
+
+ - Usage (-h) report now goes to stdout.
+
+ - Version (-V) info now goes to stdout.
+
+ - More #ifdef chud has been added to the parser in attempt to
+ deal with bison's use of alloca().
+
+ - "make clean" no longer deletes emacs backup files (*~).
+
+ - Some memory leaks have been fixed.
+
+ - A bug was fixed in which dynamically-expanded buffers were
+ reallocated a couple of bytes too small.
+
+ - A bug was fixed which could cause flex to read and write beyond
+ the end of the input buffer.
+
+ - -S will not be going away.
+
+
+Changes between release 2.4.7 (03Aug94) and release 2.4.6:
+
+ - Fixed serious bug in reading multiple files.
+
+ - Fixed bug in scanning NUL's.
+
+ - Fixed bug in input() returning 8-bit characters.
+
+ - Fixed bug in matching text with embedded NUL's when
+ using %array or lex compatibility.
+
+ - Fixed multiple invocations of YY_USER_ACTION when using '|'
+ continuation action.
+
+ - Minor prototyping fixes.
+
+Changes between release 2.4.6 (04Jan94) and release 2.4.5:
+
+ - Linking with -lfl no longer required if your program includes
+ its own yywrap() and main() functions. (This change will cause
+ problems if you have a non-ANSI compiler on a system for which
+ sizeof(int) != sizeof(void*) or sizeof(int) != sizeof(size_t).)
+
+ - The use of 'extern "C++"' in FlexLexer.h has been modified to
+ get around an incompatibility with g++'s header files.
+
+Changes between release 2.4.5 (11Dec93) and release 2.4.4:
+
+ - Fixed bug breaking C++ scanners that use REJECT or variable
+ trailing context.
+
+ - Fixed serious input problem for interactive scanners on
+ systems for which char is unsigned.
+
+ - Fixed bug in incorrectly treating '$' operator as variable
+ trailing context.
+
+ - Fixed bug in -CF table representation that could lead to
+ corrupt tables.
+
+ - Fixed fairly benign memory leak.
+
+ - Added `extern "C++"' wrapper to FlexLexer.h header. This
+ should overcome the g++ 2.5.X problems mentioned in the
+ NEWS for release 2.4.3.
+
+ - Changed #include of FlexLexer.h to use <> instead of "".
+
+ - Added feature to control whether the scanner attempts to
+ refill the input buffer once it's exhausted. This feature
+ will be documented in the 2.5 release.
+
+
+Changes between release 2.4.4 (07Dec93) and release 2.4.3:
+
+ - Fixed two serious bugs in scanning 8-bit characters.
+
+ - Fixed bug in YY_USER_ACTION that caused it to be executed
+ inappropriately (on the scanner's own internal actions, and
+ with incorrect yytext/yyleng values).
+
+ - Fixed bug in pointing yyin at a new file and resuming scanning.
+
+ - Portability fix regarding min/max/abs macros conflicting with
+ function definitions in standard header files.
+
+ - Added a virtual LexerError() method to the C++ yyFlexLexer class
+ for reporting error messages instead of always using cerr.
+
+ - Added warning in flexdoc that the C++ scanning class is presently
+ experimental and subject to considerable change between major
+ releases.
+
+
+Changes between release 2.4.3 (03Dec93) and release 2.4.2:
+
+ - Fixed bug causing fatal scanner messages to fail to print.
+
+ - Fixed things so FlexLexer.h can be included in other C++
+ sources. One side-effect of this change is that -+ and -CF
+ are now incompatible.
+
+ - libfl.a now supplies private versions of the the <string.h>/
+ <strings.h> string routines needed by flex and the scanners
+ it generates, to enhance portability to some BSD systems.
+
+ - More robust solution to 2.4.2's flexfatal() bug fix.
+
+ - Added ranlib of installed libfl.a.
+
+ - Some lint tweaks.
+
+ - NOTE: problems have been encountered attempting to build flex
+ C++ scanners using g++ version 2.5.X. The problem is due to an
+ unfortunate heuristic in g++ 2.5.X that attempts to discern between
+ C and C++ headers. Because FlexLexer.h is installed (by default)
+ in /usr/local/include and not /usr/local/lib/g++-include, g++ 2.5.X
+ decides that it's a C header :-(. So if you have problems, install
+ the header in /usr/local/lib/g++-include instead.
+
+
+Changes between release 2.4.2 (01Dec93) and release 2.4.1:
+
+ - Fixed bug in libfl.a referring to non-existent "flexfatal" function.
+
+ - Modified to produce both compress'd and gzip'd tar files for
+ distributions (you probably don't care about this change!).
+
+
+Changes between release 2.4.1 (30Nov93) and release 2.3.8:
+
+ - The new '-+' flag instructs flex to generate a C++ scanner class
+ (thanks to Kent Williams). flex writes an implementation of the
+ class defined in FlexLexer.h to lex.yy.cc. You may include
+ multiple scanner classes in your program using the -P flag. Note
+ that the scanner class also provides a mechanism for creating
+ reentrant scanners. The scanner class uses C++ streams for I/O
+ instead of FILE*'s (thanks to Tom Epperly). If the flex executable's
+ name ends in '+' then the '-+' flag is automatically on, so creating
+ a symlink or copy of "flex" to "flex++" results in a version of
+ flex that can be used exclusively for C++ scanners.
+
+ Note that without the '-+' flag, flex-generated scanners can still
+ be compiled using C++ compilers, though they use FILE*'s for I/O
+ instead of streams.
+
+ See the "GENERATING C++ SCANNERS" section of flexdoc for details.
+
+ - The new '-l' flag turns on maximum AT&T lex compatibility. In
+ particular, -l includes support for "yylineno" and makes yytext
+ be an array instead of a pointer. It does not, however, do away
+ with all incompatibilities. See the "INCOMPATIBILITIES WITH LEX
+ AND POSIX" section of flexdoc for details.
+
+ - The new '-P' option specifies a prefix to use other than "yy"
+ for the scanner's globally-visible variables, and for the
+ "lex.yy.c" filename. Using -P you can link together multiple
+ flex scanners in the same executable.
+
+ - The distribution includes a "texinfo" version of flexdoc.1,
+ contributed by Roland Pesch (thanks also to Marq Kole, who
+ contributed another version). It has not been brought up to
+ date, but reflects version 2.3. See MISC/flex.texinfo.
+
+ The flex distribution will soon include G.T. Nicol's flex
+ manual; he is presently bringing it up-to-date for version 2.4.
+
+ - yywrap() is now a function, and you now *must* link flex scanners
+ with libfl.a.
+
+ - Site-configuration is now done via an autoconf-generated
+ "configure" script contributed by Francois Pinard.
+
+ - Scanners now use fread() (or getc(), if interactive) and not
+ read() for input. A new "table compression" option, -Cr,
+ overrides this change and causes the scanner to use read()
+ (because read() is a bit faster than fread()). -f and -F
+ are now equivalent to -Cfr and -CFr; i.e., they imply the
+ -Cr option.
+
+ - In the blessed name of POSIX compliance, flex supports "%array"
+ and "%pointer" directives in the definitions (first) section of
+ the scanner specification. The former specifies that yytext
+ should be an array (of size YYLMAX), the latter, that it should
+ be a pointer. The array version of yytext is universally slower
+ than the pointer version, but has the advantage that its contents
+ remain unmodified across calls to input() and unput() (the pointer
+ version of yytext is, still, trashed by such calls).
+
+ "%array" cannot be used with the '-+' C++ scanner class option.
+
+ - The new '-Ca' option directs flex to trade off memory for
+ natural alignment when generating a scanner's tables. In
+ particular, table entries that would otherwise be "short"
+ become "long".
+
+ - The new '-h' option produces a summary of the flex flags.
+
+ - The new '-V' option reports the flex version number and exits.
+
+ - The new scanner macro YY_START returns an integer value
+ corresponding to the current start condition. You can return
+ to that start condition by passing the value to a subsequent
+ "BEGIN" action. You also can implement "start condition stacks"
+ by storing the values in an integer stack.
+
+ - You can now redefine macros such as YY_INPUT by just #define'ing
+ them to some other value in the first section of the flex input;
+ no need to first #undef them.
+
+ - flex now generates warnings for rules that can't be matched.
+ These warnings can be turned off using the new '-w' flag. If
+ your scanner uses REJECT then you will not get these warnings.
+
+ - If you specify the '-s' flag but the default rule can be matched,
+ flex now generates a warning.
+
+ - "yyleng" is now a global, and may be modified by the user (though
+ doing so and then using yymore() will yield weird results).
+
+ - Name definitions in the first section of a scanner specification
+ can now include a leading '^' or trailing '$' operator. In this
+ case, the definition is *not* pushed back inside of parentheses.
+
+ - Scanners with compressed tables are now "interactive" (-I option)
+ by default. You can suppress this attribute (which makes them
+ run slightly slower) using the new '-B' flag.
+
+ - Flex now generates 8-bit scanners by default, unless you use the
+ -Cf or -CF compression options (-Cfe and -CFe result in 8-bit
+ scanners). You can force it to generate a 7-bit scanner using
+ the new '-7' flag. You can build flex to generate 8-bit scanners
+ for -Cf and -CF, too, by adding -DDEFAULT_CSIZE=256 to CFLAGS
+ in the Makefile.
+
+ - You no longer need to call the scanner routine yyrestart() to
+ inform the scanner that you have switched to a new file after
+ having seen an EOF on the current input file. Instead, just
+ point yyin at the new file and continue scanning.
+
+ - You no longer need to invoke YY_NEW_FILE in an <<EOF>> action
+ to indicate you wish to continue scanning. Simply point yyin
+ at a new file.
+
+ - A leading '#' no longer introduces a comment in a flex input.
+
+ - flex no longer considers formfeed ('\f') a whitespace character.
+
+ - %t, I'm happy to report, has been nuked.
+
+ - The '-p' option may be given twice ('-pp') to instruct flex to
+ report minor performance problems as well as major ones.
+
+ - The '-v' verbose output no longer includes start/finish time
+ information.
+
+ - Newlines in flex inputs can optionally include leading or
+ trailing carriage-returns ('\r'), in support of several PC/Mac
+ run-time libraries that automatically include these.
+
+ - A start condition of the form "<*>" makes the following rule
+ active in every start condition, whether exclusive or inclusive.
+
+ - The following items have been corrected in the flex documentation:
+
+ - '-C' table compression options *are* cumulative.
+
+ - You may modify yytext but not lengthen it by appending
+ characters to the end. Modifying its final character
+ will affect '^' anchoring for the next rule matched
+ if the character is changed to or from a newline.
+
+ - The term "backtracking" has been renamed "backing up",
+ since it is a one-time repositioning and not a repeated
+ search. What used to be the "lex.backtrack" file is now
+ "lex.backup".
+
+ - Unindented "/* ... */" comments are allowed in the first
+ flex input section, but not in the second.
+
+ - yyless() can only be used in the flex input source, not
+ externally.
+
+ - You can use "yyrestart(yyin)" to throw away the
+ current contents of the input buffer.
+
+ - To write high-speed scanners, attempt to match as much
+ text as possible with each rule. See MISC/fastwc/README
+ for more information.
+
+ - Using the beginning-of-line operator ('^') is fairly
+ cheap. Using unput() is expensive. Using yyless() is
+ cheap.
+
+ - An example of scanning strings with embedded escape
+ sequences has been added.
+
+ - The example of backing-up in flexdoc was erroneous; it
+ has been corrected.
+
+ - A flex scanner's internal buffer now dynamically grows if needed
+ to match large tokens. Note that growing the buffer presently
+ requires rescanning the (large) token, so consuming a lot of
+ text this way is a slow process. Also note that presently the
+ buffer does *not* grow if you unput() more text than can fit
+ into the buffer.
+
+ - The MISC/ directory has been reorganized; see MISC/README for
+ details.
+
+ - yyless() can now be used in the third (user action) section
+ of a scanner specification, thanks to Ceriel Jacobs. yyless()
+ remains a macro and cannot be used outside of the scanner source.
+
+ - The skeleton file is no longer opened at run-time, but instead
+ compiled into a large string array (thanks to John Gilmore and
+ friends at Cygnus). You can still use the -S flag to point flex
+ at a different skeleton file.
+
+ - flex no longer uses a temporary file to store the scanner's
+ actions.
+
+ - A number of changes have been made to decrease porting headaches.
+ In particular, flex no longer uses memset() or ctime(), and
+ provides a single simple mechanism for dealing with C compilers
+ that still define malloc() as returning char* instead of void*.
+
+ - Flex now detects if the scanner specification requires the -8 flag
+ but the flag was not given or on by default.
+
+ - A number of table-expansion fencepost bugs have been fixed,
+ making flex more robust for generating large scanners.
+
+ - flex more consistently identifies the location of errors in
+ its input.
+
+ - YY_USER_ACTION is now invoked only for "real" actions, not for
+ internal actions used by the scanner for things like filling
+ the buffer or handling EOF.
+
+ - The rule "[^]]" now matches any character other than a ']';
+ formerly it matched any character at all followed by a ']'.
+ This change was made for compatibility with AT&T lex.
+
+ - A large number of miscellaneous bugs have been found and fixed
+ thanks to Gerhard Wilhelms.
+
+ - The source code has been heavily reformatted, making patches
+ relative to previous flex releases no longer accurate.
+
+
+Changes between 2.3 Patch #8 (21Feb93) and 2.3 Patch #7:
+
+ - Fixed bugs in dynamic memory allocation leading to grievous
+ fencepost problems when generating large scanners.
+ - Fixed bug causing infinite loops on character classes with 8-bit
+ characters in them.
+ - Fixed bug in matching repetitions with a lower bound of 0.
+ - Fixed bug in scanning NUL characters using an "interactive" scanner.
+ - Fixed bug in using yymore() at the end of a file.
+ - Fixed bug in misrecognizing rules with variable trailing context.
+ - Fixed bug compiling flex on Suns using gcc 2.
+ - Fixed bug in not recognizing that input files with the character
+ ASCII 128 in them require the -8 flag.
+ - Fixed bug that could cause an infinite loop writing out
+ error messages.
+ - Fixed bug in not recognizing old-style lex % declarations if
+ followed by a tab instead of a space.
+ - Fixed potential crash when flex terminated early (usually due
+ to a bad flag) and the -v flag had been given.
+ - Added some missing declarations of void functions.
+ - Changed to only use '\a' for __STDC__ compilers.
+ - Updated mailing addresses.
+
+
+Changes between 2.3 Patch #7 (28Mar91) and 2.3 Patch #6:
+
+ - Fixed out-of-bounds array access that caused bad tables
+ to be produced on machines where the bad reference happened
+ to yield a 1. This caused problems installing or running
+ flex on some Suns, in particular.
+
+
+Changes between 2.3 Patch #6 (29Aug90) and 2.3 Patch #5:
+
+ - Fixed a serious bug in yymore() which basically made it
+ completely broken. Thanks goes to Jean Christophe of
+ the Nethack development team for finding the problem
+ and passing along the fix.
+
+
+Changes between 2.3 Patch #5 (16Aug90) and 2.3 Patch #4:
+
+ - An up-to-date version of initscan.c so "make test" will
+ work after applying the previous patches
+
+
+Changes between 2.3 Patch #4 (14Aug90) and 2.3 Patch #3:
+
+ - Fixed bug in hexadecimal escapes which allowed only digits,
+ not letters, in escapes
+ - Fixed bug in previous "Changes" file!
+
+
+Changes between 2.3 Patch #3 (03Aug90) and 2.3 Patch #2:
+
+ - Correction to patch #2 for gcc compilation; thanks goes to
+ Paul Eggert for catching this.
+
+
+Changes between 2.3 Patch #2 (02Aug90) and original 2.3 release:
+
+ - Fixed (hopefully) headaches involving declaring malloc()
+ and free() for gcc, which defines __STDC__ but (often) doesn't
+ come with the standard include files such as <stdlib.h>.
+ Reordered #ifdef maze in the scanner skeleton in the hope of
+ getting the declarations right for cfront and g++, too.
+
+ - Note that this patch supercedes patch #1 for release 2.3,
+ which was never announced but was available briefly for
+ anonymous ftp.
+
+
+Changes between 2.3 (full) release of 28Jun90 and 2.2 (alpha) release:
+
+ User-visible:
+
+ - A lone <<EOF>> rule (that is, one which is not qualified with
+ a list of start conditions) now specifies the EOF action for
+ *all* start conditions which haven't already had <<EOF>> actions
+ given. To specify an end-of-file action for just the initial
+ state, use <INITIAL><<EOF>>.
+
+ - -d debug output is now contigent on the global yy_flex_debug
+ being set to a non-zero value, which it is by default.
+
+ - A new macro, YY_USER_INIT, is provided for the user to specify
+ initialization action to be taken on the first call to the
+ scanner. This action is done before the scanner does its
+ own initialization.
+
+ - yy_new_buffer() has been added as an alias for yy_create_buffer()
+
+ - Comments beginning with '#' and extending to the end of the line
+ now work, but have been deprecated (in anticipation of making
+ flex recognize #line directives).
+
+ - The funky restrictions on when semi-colons could follow the
+ YY_NEW_FILE and yyless macros have been removed. They now
+ behave identically to functions.
+
+ - A bug in the sample redefinition of YY_INPUT in the documentation
+ has been corrected.
+
+ - A bug in the sample simple tokener in the documentation has
+ been corrected.
+
+ - The documentation on the incompatibilities between flex and
+ lex has been reordered so that the discussion of yylineno
+ and input() come first, as it's anticipated that these will
+ be the most common source of headaches.
+
+
+ Things which didn't used to be documented but now are:
+
+ - flex interprets "^foo|bar" differently from lex. flex interprets
+ it as "match either a 'foo' or a 'bar', providing it comes at the
+ beginning of a line", whereas lex interprets it as "match either
+ a 'foo' at the beginning of a line, or a 'bar' anywhere".
+
+ - flex initializes the global "yyin" on the first call to the
+ scanner, while lex initializes it at compile-time.
+
+ - yy_switch_to_buffer() can be used in the yywrap() macro/routine.
+
+ - flex scanners do not use stdio for their input, and hence when
+ writing an interactive scanner one must explictly call fflush()
+ after writing out a prompt.
+
+ - flex scanner can be made reentrant (after a fashion) by using
+ "yyrestart( yyin );". This is useful for interactive scanners
+ which have interrupt handlers that long-jump out of the scanner.
+
+ - a defense of why yylineno is not supported is included, along
+ with a suggestion on how to convert scanners which rely on it.
+
+
+ Other changes:
+
+ - Prototypes and proper declarations of void routines have
+ been added to the flex source code, courtesy of Kevin B. Kenny.
+
+ - Routines dealing with memory allocation now use void* pointers
+ instead of char* - see Makefile for porting implications.
+
+ - Error-checking is now done when flex closes a file.
+
+ - Various lint tweaks were added to reduce the number of gripes.
+
+ - Makefile has been further parameterized to aid in porting.
+
+ - Support for SCO Unix added.
+
+ - Flex now sports the latest & greatest UC copyright notice
+ (which is only slightly different from the previous one).
+
+ - A note has been added to flexdoc.1 mentioning work in progress
+ on modifying flex to generate straight C code rather than a
+ table-driven automaton, with an email address of whom to contact
+ if you are working along similar lines.
+
+
+Changes between 2.2 Patch #3 (30Mar90) and 2.2 Patch #2:
+
+ - fixed bug which caused -I scanners to bomb
+
+
+Changes between 2.2 Patch #2 (27Mar90) and 2.2 Patch #1:
+
+ - fixed bug writing past end of input buffer in yyunput()
+ - fixed bug detecting NUL's at the end of a buffer
+
+
+Changes between 2.2 Patch #1 (23Mar90) and 2.2 (alpha) release:
+
+ - Makefile fixes: definition of MAKE variable for systems
+ which don't have it; installation of flexdoc.1 along with
+ flex.1; fixed two bugs which could cause "bigtest" to fail.
+
+ - flex.skel fix for compiling with g++.
+
+ - README and flexdoc.1 no longer list an out-of-date BITNET address
+ for contacting me.
+
+ - minor typos and formatting changes to flex.1 and flexdoc.1.
+
+
+Changes between 2.2 (alpha) release of March '90 and previous release:
+
+ User-visible:
+
+ - Full user documentation now available.
+
+ - Support for 8-bit scanners.
+
+ - Scanners now accept NUL's.
+
+ - A facility has been added for dealing with multiple
+ input buffers.
+
+ - Two manual entries now. One which fully describes flex
+ (rather than just its differences from lex), and the
+ other for quick(er) reference.
+
+ - A number of changes to bring flex closer into compliance
+ with the latest POSIX lex draft:
+
+ %t support
+ flex now accepts multiple input files and concatenates
+ them together to form its input
+ previous -c (compress) flag renamed -C
+ do-nothing -c and -n flags added
+ Any indented code or code within %{}'s in section 2 is
+ now copied to the output
+
+ - yyleng is now a bona fide global integer.
+
+ - -d debug information now gives the line number of the
+ matched rule instead of which number rule it was from
+ the beginning of the file.
+
+ - -v output now includes a summary of the flags used to generate
+ the scanner.
+
+ - unput() and yyrestart() are now globally callable.
+
+ - yyrestart() no longer closes the previous value of yyin.
+
+ - C++ support; generated scanners can be compiled with C++ compiler.
+
+ - Primitive -lfl library added, containing default main()
+ which calls yylex(). A number of routines currently living
+ in the scanner skeleton will probably migrate to here
+ in the future (in particular, yywrap() will probably cease
+ to be a macro and instead be a function in the -lfl library).
+
+ - Hexadecimal (\x) escape sequences added.
+
+ - Support for MS-DOS, VMS, and Turbo-C integrated.
+
+ - The %used/%unused operators have been deprecated. They
+ may go away soon.
+
+
+ Other changes:
+
+ - Makefile enhanced for easier testing and installation.
+ - The parser has been tweaked to detect some erroneous
+ constructions which previously were missed.
+ - Scanner input buffer overflow is now detected.
+ - Bugs with missing "const" declarations fixed.
+ - Out-of-date Minix/Atari patches provided.
+ - Scanners no longer require printf() unless FLEX_DEBUG is being used.
+ - A subtle input() bug has been fixed.
+ - Line numbers for "continued action" rules (those following
+ the special '|' action) are now correct.
+ - unput() bug fixed; had been causing problems porting flex to VMS.
+ - yymore() handling rewritten to fix bug with interaction
+ between yymore() and trailing context.
+ - EOF in actions now generates an error message.
+ - Bug involving -CFe and generating equivalence classes fixed.
+ - Bug which made -CF be treated as -Cf fixed.
+ - Support for SysV tmpnam() added.
+ - Unused #define's for scanner no longer generated.
+ - Error messages which are associated with a particular input
+ line are now all identified with their input line in standard
+ format.
+ - % directives which are valid to lex but not to flex are
+ now ignored instead of generating warnings.
+ - -DSYS_V flag can now also be specified -DUSG for System V
+ compilation.
+
+
+Changes between 2.1 beta-test release of June '89 and previous release:
+
+ User-visible:
+
+ - -p flag generates a performance report to stderr. The report
+ consists of comments regarding features of the scanner rules
+ which result in slower scanners.
+
+ - -b flag generates backtracking information to lex.backtrack.
+ This is a list of scanner states which require backtracking
+ and the characters on which they do so. By adding rules
+ one can remove backtracking states. If all backtracking states
+ are eliminated, the generated scanner will run faster.
+ Backtracking is not yet documented in the manual entry.
+
+ - Variable trailing context now works, i.e., one can have
+ rules like "(foo)*/[ \t]*bletch". Some trailing context
+ patterns still cannot be properly matched and generate
+ error messages. These are patterns where the ending of the
+ first part of the rule matches the beginning of the second
+ part, such as "zx*/xy*", where the 'x*' matches the 'x' at
+ the beginning of the trailing context. Lex won't get these
+ patterns right either.
+
+ - Faster scanners.
+
+ - End-of-file rules. The special rule "<<EOF>>" indicates
+ actions which are to be taken when an end-of-file is
+ encountered and yywrap() returns non-zero (i.e., indicates
+ no further files to process). See manual entry for example.
+
+ - The -r (reject used) flag is gone. flex now scans the input
+ for occurrences of the string "REJECT" to determine if the
+ action is needed. It tries to be intelligent about this but
+ can be fooled. One can force the presence or absence of
+ REJECT by adding a line in the first section of the form
+ "%used REJECT" or "%unused REJECT".
+
+ - yymore() has been implemented. Similarly to REJECT, flex
+ detects the use of yymore(), which can be overridden using
+ "%used" or "%unused".
+
+ - Patterns like "x{0,3}" now work (i.e., with lower-limit == 0).
+
+ - Removed '\^x' for ctrl-x misfeature.
+
+ - Added '\a' and '\v' escape sequences.
+
+ - \<digits> now works for octal escape sequences; previously
+ \0<digits> was required.
+
+ - Better error reporting; line numbers are associated with rules.
+
+ - yyleng is a macro; it cannot be accessed outside of the
+ scanner source file.
+
+ - yytext and yyleng should not be modified within a flex action.
+
+ - Generated scanners #define the name FLEX_SCANNER.
+
+ - Rules are internally separated by YY_BREAK in lex.yy.c rather
+ than break, to allow redefinition.
+
+ - The macro YY_USER_ACTION can be redefined to provide an action
+ which is always executed prior to the matched rule's action.
+
+ - yyrestart() is a new action which can be used to restart
+ the scanner after it has seen an end-of-file (a "real" one,
+ that is, one for which yywrap() returned non-zero). It takes
+ a FILE* argument indicating a new file to scan and sets
+ things up so that a subsequent call to yylex() will start
+ scanning that file.
+
+ - Internal scanner names all preceded by "yy_"
+
+ - lex.yy.c is deleted if errors are encountered during processing.
+
+ - Comments may be put in the first section of the input by preceding
+ them with '#'.
+
+
+
+ Other changes:
+
+ - Some portability-related bugs fixed, in particular for machines
+ with unsigned characters or sizeof( int* ) != sizeof( int ).
+ Also, tweaks for VMS and Microsoft C (MS-DOS), and identifiers all
+ trimmed to be 31 or fewer characters. Shortened file names
+ for dinosaur OS's. Checks for allocating > 64K memory
+ on 16 bit'ers. Amiga tweaks. Compiles using gcc on a Sun-3.
+ - Compressed and fast scanner skeletons merged.
+ - Skeleton header files done away with.
+ - Generated scanner uses prototypes and "const" for __STDC__.
+ - -DSV flag is now -DSYS_V for System V compilation.
+ - Removed all references to FTL language.
+ - Software now covered by BSD Copyright.
+ - flex will replace lex in subsequent BSD releases.