mirror of https://github.com/ZDoom/gzdoom-gles.git
189 lines
6.2 KiB
Plaintext
189 lines
6.2 KiB
Plaintext
re2c Version 0.12.3
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------------------
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Originally written by Peter Bumbulis (peter@csg.uwaterloo.ca)
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Currently maintained by:
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Dan Nuffer <nuffer at users.sourceforge.net>
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Marcus Boerger <helly at users.sourceforge.net>
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Hartmut Kaiser <hkaiser at users.sourceforge.net>
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The re2c distribution can be found at:
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http://sourceforge.net/projects/re2c/
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re2c has been developed and tested with the following compilers on various
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platforms in 32 bit and 64 bit mode:
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- GCC 3.3 ... 4.1
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- Microsoft VC 7, 7.1, 8
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- Intel 9.0
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- Sun C++ 5.8 (CXXFLAGS='-library=stlport4')
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- MIPSpro Compilers: Version 7.4.4m
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GCC 2.x and Microsoft VC 6 are not capable of compiling re2c.
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Building re2c on unix like platforms requires autoconf 2.57 and bison (tested
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with 1.875 and later). Under windows you don't need autoconf or bison
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and can use the pregenerated files.
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You can build this software by simply typing the following commands:
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./configure
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make
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The above version will be based on the pregenerated scanner.cc file.
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If you want to build that file yourself (recommended when installing
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re2c) you need the following steps:
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./configure
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make
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rm -f scanner.cc
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make install
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Or you can create a rpm package and install it by the following commands:
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./configure
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make rpm
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rpm -Uhv <packagedir>/re2c-0.12.3-1.rpm
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If you want to build from CVS then the first thing you should do is
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regenerating all build files using the following command:
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./autogen.sh
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and then continue with one of the above described build methods. Or if you
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need to generate RPM packages for cvs builds use these commands:
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./autogen.sh
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./configure
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./makerpm <release>
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rpm -Uhv <packagedir>/re2c-0.12.3-<release>.rpm
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Here <realease> should be a number like 1. And <packagedir> must equal
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the directory where the makerpm step has written the generated rpm to.
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If you are on a debian system you can use the tool 'alien' to convert rpms
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to debian packages.
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When building with native SUN compilers you need to set the following compiler
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flags: CXXFLAGS='-g -compat5 -library=stlport4'.
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If you want to build re2c on a windows system you can either use cygwin and one
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of the methods described above or use Microsoft Visual C .NET 2002 or later
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with the solution files provided (re2c.sln for 2002/2003 and re2c-2005.sln for
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version 2005). re2c cannot be built with Microsoft Visual C 6.0 or earlier.
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re2c is a great tool for writing fast and flexible lexers. It has
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served many people well for many years. re2c is on the order of 2-3
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times faster than a flex based scanner, and its input model is much
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more flexible.
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For an introduction to re2c refer to the lessons sub directory.
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Peter's original version 0.5 ANNOUNCE and README follows.
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--
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re2c is a tool for generating C-based recognizers from regular
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expressions. re2c-based scanners are efficient: for programming
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languages, given similar specifications, an re2c-based scanner is
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typically almost twice as fast as a flex-based scanner with little or no
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increase in size (possibly a decrease on cisc architectures). Indeed,
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re2c-based scanners are quite competitive with hand-crafted ones.
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Unlike flex, re2c does not generate complete scanners: the user must
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supply some interface code. While this code is not bulky (about 50-100
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lines for a flex-like scanner; see the man page and examples in the
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distribution) careful coding is required for efficiency (and
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correctness). One advantage of this arrangement is that the generated
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code is not tied to any particular input model. For example, re2c
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generated code can be used to scan data from a null-byte terminated
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buffer as illustrated below.
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Given the following source
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#define NULL ((char*) 0)
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char *scan(char *p)
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{
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#define YYCTYPE char
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#define YYCURSOR p
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#define YYLIMIT p
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#define YYFILL(n)
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/*!re2c
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[0-9]+ {return YYCURSOR;}
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[\000-\377] {return NULL;}
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*/
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}
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re2c will generate
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/* Generated by re2c on Sat Apr 16 11:40:58 1994 */
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#line 1 "simple.re"
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#define NULL ((char*) 0)
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char *scan(char *p)
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{
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#define YYCTYPE char
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#define YYCURSOR p
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#define YYLIMIT p
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#define YYFILL(n)
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{
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YYCTYPE yych;
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unsigned int yyaccept;
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if((YYLIMIT - YYCURSOR) < 2) YYFILL(2);
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yych = *YYCURSOR;
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if(yych <= '/') goto yy4;
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if(yych >= ':') goto yy4;
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yy2: yych = *++YYCURSOR;
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goto yy7;
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yy3:
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#line 9
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{return YYCURSOR;}
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yy4: yych = *++YYCURSOR;
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yy5:
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#line 10
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{return NULL;}
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yy6: ++YYCURSOR;
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if(YYLIMIT == YYCURSOR) YYFILL(1);
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yych = *YYCURSOR;
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yy7: if(yych <= '/') goto yy3;
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if(yych <= '9') goto yy6;
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goto yy3;
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}
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#line 11
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}
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Note that most compilers will perform dead-code elimination to remove
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all YYCURSOR, YYLIMIT comparisions.
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re2c was developed for a particular project (constructing a fast REXX
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scanner of all things!) and so while it has some rough edges, it should
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be quite usable. More information about re2c can be found in the
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(admittedly skimpy) man page; the algorithms and heuristics used are
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described in an upcoming LOPLAS article (included in the distribution).
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Probably the best way to find out more about re2c is to try the supplied
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examples. re2c is written in C++, and is currently being developed
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under Linux using gcc 2.5.8.
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Peter
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--
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re2c is distributed with no warranty whatever. The code is certain to
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contain errors. Neither the author nor any contributor takes
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responsibility for any consequences of its use.
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re2c is in the public domain. The data structures and algorithms used
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in re2c are all either taken from documents available to the general
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public or are inventions of the author. Programs generated by re2c may
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be distributed freely. re2c itself may be distributed freely, in source
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or binary, unchanged or modified. Distributors may charge whatever fees
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they can obtain for re2c.
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If you do make use of re2c, or incorporate it into a larger project an
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acknowledgement somewhere (documentation, research report, etc.) would
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be appreciated.
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Please send bug reports and feedback (including suggestions for
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improving the distribution) to
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peter@csg.uwaterloo.ca
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Include a small example and the banner from parser.y with bug reports.
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