文件列表:

src (0, 2005-10-27)
src\awka (0, 2005-10-27)
src\awka\0.7.5 (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5 (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\awka (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\awka\Makefile (4463, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\check.log (17975, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\config.cache (3411, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\config.h (689, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\config.log (19225, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\config.status (5927, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\configure_help.txt (2567, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\lib (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\lib\Makefile (2775, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\libtool00.sed (542, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\Makefile (1966, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\Makefile.mingw (664, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\patches (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\patches\awka-0.7.5-src.diff (45984, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\regexp (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\res (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\res\awka-res.rc (4005, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\res\awka.ico (2238, 2003-10-18)
src\awka\0.7.5\awka-0.7.5\test (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\test\argarray.in (27, 2005-10-27)
src\awka\0.7.5\awka-0.7.5\test\Makefile (32527, 2005-10-27)
src\awka\0.7.5\awka-0.7.5-src (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5-src\ACKNOWLEDGEMENTS (2446, 2001-07-13)
src\awka\0.7.5\awka-0.7.5-src\awka (0, 2005-10-27)
src\awka\0.7.5\awka-0.7.5-src\awka\array.h (1380, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\awka.c (6781, 2001-07-11)
src\awka\0.7.5\awka-0.7.5-src\awka\awka.h (5132, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\awka_exe.h (20552, 2001-07-12)
src\awka\0.7.5\awka-0.7.5-src\awka\bi_funct.c (8228, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\bi_funct.h (2802, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\bi_vars.c (3893, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\bi_vars.h (1413, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\cast.c (10147, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\code.c (6785, 2001-07-06)
src\awka\0.7.5\awka-0.7.5-src\awka\code.h (6418, 2001-07-06)
... ...

INTRODUCTION ------------ Awka comprises a translator of the AWK programming language to ANSI-C, and a library against which translated programs may be linked. version 0.7.x Instructions on installing Awka may be found in the file INSTALL.TXT. SO WHAT IS AWKA? ---------------- It is two products :- * A Translator - awka - is a seriously hacked version of mawk, with additional code to output ANSI-C code. This is not a recommended way of producing a program, but (a) it's only a translator, and (b) time was too short not to use mawk as a starting point. * The Library - libawka.a - is my own creation, and is I believe(hope) much better designed than the translator. Most development time was spent on the library, ensuring that code size and execution time were the best I could produce. To my mind the most important reason for a translator is that AWK programs are limited to what the interpreter provides, whereas C code can be compiled with other code into a larger application. The use of C allows other products, such as Tk, to be used to provide GUI front-ends and the like. It also allows you to migrate stable functions from AWK to C, and still have them available to call as functions from with the AWK language. Many people have expressed the following requirements for an Awk-to-C translator; it must allow distribution of an executable, and it should deliver improved performance through removal of the interpreter. Awka provides the method for creating an executable. Increased performance, however, faced major issues:- (a) It is a common assumption that compiled code will automatically be faster than interpreted, but this is not particularly true of AWK. AWK is a relatively terse language (part of its appeal) - most things translate directly into calls to 'library' functions in the (compiled) interpreter. This means that Awka is unlikely to be much quicker than the fastest interpreter Mawk, and sometimes Mawk is faster. Only with larger AWK programs will there be any benefit from compiling; even then it may not be significant. You are also depending on how well your C compiler optimises code on your platform, something over which I have no control. (b) Variables are typeless in AWK, so they must also be typeless in the compiled code. Thus one of the main areas where savings could be made - use of C native data types - is denied to a translator. The Awka library uses macros and inline functions where possible to allow AWK-style type-casting without losing speed, and the translator cuts corners by referencing the contents of variables directly whenever it can. (c) Many AWK functions have variable numbers of arguments. An interpreter can create efficient internal parameter structures at parse time, but C code must resort to vararg calls, which are not particularly quick. Having said all this, Awka seems to be at least competitive with Mawk, and on some (but by no means all) occasions it is faster. The one area where Awka really falls behind Mawk is with recursive function calls, where Mawk approaches C in speed, but Awka is closer to Gawk. Some AWK enthusiasts may be opposed to the idea of a compiler, holding to a philosophical view that AWK scripts should always be made available in source form to customers. I feel that although this may be appropriate most of the time, sometimes it is not. With Awka, the author of a script now has more options to decide how they want their work distributed, and I think freedom of choice is a good thing. WHAT PLATFORMS ARE SUPPORTED? ----------------------------- Awka is designed to operate under a flavour of Unix. It should compile and install correctly on pretty much any machine supporting configure scripts, Makefiles and with an ANSI C compiler. Neither the Awka library or the generated C code is thread-safe. LICENSING --------- The Awka TRANSLATOR contains portions of code derived from Mawk, and therefore shares Mawk's GPL license, a copy of which is provided. Prior to release 0.7.5, the LIBRARY was distributed under the Lesser Public License. This changed to the GPL in 0.7.5 due to the inclusion of some code from Gawk to provide inet and coprocessing capabilities. A copy of the GPL is included in this distribution. If you plan to use the Awka package you should definitely read this document and become familiar with its terms. Please note that the code generated from your awk script by the TRANSLATOR is always owned by you - I do not consider it to be 'derived from' the TRANSLATOR's code, so it does not come under GPL. FEEDBACK -------- Encouragement, bug reports (patches are welcome), suggestions, bribes and constructive criticism may be sent to andrewsumner@yahoo.com. I don't always have time to read my mail or to reply promptly, but I will do my best. The Awka homepage is at: http://awka.sourceforge.net The most current source release will always be posted here, and new releases are announced in comp.lang.awk and at freshmeat.net. HOW AWKA CAME TO BE ------------------- Awka was developed in response to several posts to comp.lang.awk asking whether a free awk translator/compiler existed - clearly there was a need for such a tool. Responses to these queries usually pointed to TAWK, apparently a fine product; however it is not free, and is not available for many platforms. From what I can gather Tawk produces assembler or machine-language output which it then executes, rather than generating portable C code. I found some references to an ancient tool called CAWK, which is apparently 'Compiled AWK', however I could find nothing about it - certainly if it exists it is not available for general distribution. There is also awk2c, which creates C code to link to gawk sourcecode, however this was incomplete, with no development taking place. It also appeared to be subject to the GPL, so distribution of binaries without sourcecode may not have been possible. As it used native C datatypes it would have been difficult to integrate it with a library providing the builtin C functions. Finally there was awkcc, an AT&T product that is essentially similar to Awka but costs $2,000 for a sublicense (or did when I last checked). "Implementors of the AWK language have shown a consistent lack of imagination when naming their programs." - Michael Brennan Over time I had been creating a library of awk-like functions, which I had called libawka (Awka stood for Awk Archive). I extended this to make it a more complete coverage of the language, including pervasive casting of variable types. I then tackled the task of writing a translator - something I had little time to do properly. In order to reduce the size of the task I decided to use Mawk as a starting point. I tried to remove as much execution code as possible, leaving code necessary for parsing the AWK language. I converted the Mawk internal opcode structure to a format I could use for translation purposes, then crunched out a translation module. I preferred Mawk over Gawk as I found it easier to track variable types in complex statements using Mawk's reverse-polish, assembler-like opcode structure. At the time I was not aware of various Mawk parser bugs and restrictions, and these caused sufficient problems to make me attempt using Gawk's parser, however this proved too complex, so I persevered with Mawk's. In retrospect it would have been preferable to use Gawk as a starting point, and potentially one day Awka may move to using Gawk's language parser. I borrowed Gawk's extensive test suite and, after much effort removing various bugs and incorrect logic (from Awka not Gawk), I ensured that Awka now passes the tests. The test suite is being extended as new bugs are discovered and fixed. A major enhancement introduced in version 0.7.0 is the ability to write your own C functions, and have them available in the AWK language as if they were builtin functions. See the awka-elm manpage for more details about this, as it really frees the AWK language in a way that hasn't been done before. Andrew Sumner, August 2000.

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