Game Command Language (GCL) is a scripting language developed by KCE Japan West for Metal Gear Solid. GCL is compiled to bytecode and relies on an interpreter library (LibGCL) in the system program. Tcl was used for reference when designing the language.
The language was designed with the use of Japanese identifiers in mind, as the members of the script unit found it easier to work in their native language.
GCL is statically typed, as dynamic typing is prone to creating bugs in the hands of the script unit, which mainly consisted of non-programmers (e.g. game designers and planners).
Comments are handled the same as in C/C++, as well as with the # character for a single-line comment.
GCL supports C-like preprocessor directives.
Source files use EUC-JP encoding. This must be kept standard across files; if different encodings are used, the hash of what may appear to have been the same string will not match.
See the examples page for excerpts from various games.
An in-house tool was developed for compiling GCL scripts. The tool for MGS1 was named "GCLCONV" and was written by lead programmer Kazunobu Uehara.
The compiled files will be named "scenerio.gcx" and sorted into the proper stage. There can also be additional GCX files in a given stage. In MGS1, the demo theater sequence executes "demo.gcx", and MGS2's boss rush mode executes "boss.gcx".
RADIO.DAT in MGS1 and CODEC.DAT in following games contain GCX scripts concatenated into a streaming-type DAT archive.
The "scenerio" misspelling has persisted from MGS1 into MGS3D. Konami has since dropped GCL in favor of Lua scripting for the Fox Engine.
The equivalent compiled files in ZOE and ZOE2 have the extension "SCX" and are named after the stage they control. For example: stage/gl1/gl1.scx
The interpreter library is named LibSCN.
The first four bytes of each GCX script (excluding MGS1) are a Unix hexadecimal timestamp in little endian byte order. All scripts for a given build of a game in both stage and codec share the same timestamp.
Convert to big endian and input it into a conversion tool to see when the scripts were compiled.
| Hex Value (LE) | Title | Product Code/Notes | Time (GMT) |
|---|---|---|---|
| ACC4133A | MGS2 Trial Edition | SLPM-62043 | November 16, 2000 11:27:40 AM |
| E18D343A | MGS2 Trial Edition | SLUS-29003 | December 11, 2000 8:18:41 AM |
| E18D343A | MGS2 Trial Edition | SLED-50117 | December 11, 2000 8:18:41 AM |
| 7191B23B | MGS2 Sons of Liberty | SLUS-20144 | September 27, 2001 2:39:45 AM |
| 33F8C43B | MGS2 Sons of Liberty | SLPM-65078 | October 11, 2001 1:38:59 AM |
| ? | MGS2 Sons of Liberty | SLES-50383, En/Fr/De | |
| ? | MGS2 Sons of Liberty | EU, Italian | |
| ? | MGS2 Sons of Liberty | EU, Spanish | |
| ? | MGS2 Sons of Liberty | SLPM-67515, Korean | |
| 0281273D | Document of MGS2 | SLPM-65184, DOCUMENT | July 6, 2002 11:45:06 PM |
| 33B3293D | Document of MGS2 | SLUS-20543, DOCUMENT | July 8, 2002 3:43:47 PM |
| F1DE323D | Document of MGS2 | SLES-82010, DOCUMENT | July 15, 2002 2:40:49 PM |
| AAB5123D | Document of MGS2 | SLPM-65184, MGS2 | June 21, 2002 5:12:10 AM |
| AAB5123D | Document of MGS2 | SLUS-20543, MGS2 | June 21, 2002 5:12:10 AM |
| AAB5123D | Document of MGS2 | SLES-82010, MGS2 | June 21, 2002 5:12:10 AM |
| FE7A2E3D | MGS2 Substance | US Xbox, KN007 1.06 | July 12, 2002 6:45:18 AM |
| B92A903D | MGS2 Substance | EU Xbox, KN007 1.08 | September 24, 2002 9:04:57 AM |
| B92A903D | MGS2 Substance | EU Win | September 24, 2002 9:04:57 AM |
| B92A903D | MGS2 Substance | US Win | September 24, 2002 9:04:57 AM |
| 3D88923D | MGS2 Substance | SLUS-20554 | September 26, 2002 4:08:29 AM |
| ? | MGS2 Substance | SLPM-67002 | |
| ? | MGS2 Substance | SLES-82009 | |
| ? | MGS2 Substance | SLKA-35001 | |
| D7B8E13F | MGS The Twin Snakes | US Debug v099.1 | December 18, 2003 2:25:27 PM |
| C35C1C40 | MGS The Twin Snakes | DOL-P-GGSE | February 1, 2004 1:56:19 AM |
| 44AA2140 | MGS The Twin Snakes | DOL-P-GGSJ | February 5, 2004 2:28:20 AM |
| D9912240 | MGS The Twin Snakes | DOL-P-GGSP | February 5, 2004 6:56:25 PM |
| 85A0DA40 | MGS3 Trial Edition | SCUS-97339 | June 24, 2004 9:36:05 AM |
| DC156341 | MGS3 Snake Eater | SLPM-65790 | October 5, 2004 9:45:00 PM |
| BEBA6541 | MGS3 Snake Eater | SLUS-20915 | October 7, 2004 9:53:02 PM |
| ? | MGS3 Snake Eater | EU, English/French | |
| ? | MGS3 Snake Eater | EU, German | |
| ? | MGS3 Snake Eater | EU, Italian | |
| ? | MGS3 Snake Eater | EU, Spanish | |
| ? | MGS3 Snake Eater | SLKA-25251 | |
| 32DC9941 | MG AC!D | ULJM-05001 | November 16, 2004 10:53:38 AM |
| D268EC41 | MG AC!D | ULUS-10006 | January 18, 2005 1:39:30 AM |
| D268EC41 | MG AC!D | ULES-00008 | January 18, 2005 1:39:30 AM |
| 5FFE4243 | MG AC!D 2 | ULJM-05047 | October 4, 2005 10:12:47 PM |
| 8EEB8F43 | MG AC!D 2 | ULUS-10077 | December 2, 2005 6:37:02 AM |
| 8EEB8F43 | MG AC!D 2 | ULKS-46065 | December 2, 2005 6:37:02 AM |
| 8EEB8F43 | MG AC!D 2 | ULES-00284 | December 2, 2005 6:37:02 AM |
| D3743843 | MGS3 Subsistence | SLPM-66220~2 | September 26, 2005 10:23:15 PM |
| DBBE7143 | MGS3 Subsistence | SLUS-21359 (+2) | November 9, 2005 9:18:19 AM |
| 20DC8643 | MGS3 Subsistence | SLKA-25353~5 | November 25, 2005 9:40:48 AM |
| 05D3D543 | MGS3 Subsistence | EU, Italian | January 24, 2006 7:11:01 AM |
| A3F7DF43 | MGS3 Subsistence | EU, German | January 31, 2006 11:49:55 PM |
| 0FD3E643 | MGS3 Subsistence | EU, English/French | February 6, 2006 4:39:43 AM |
| 79DDE643 | MGS3 Subsistence | EU, Spanish | February 6, 2006 5:24:09 AM |
| FB57F143 | MGS3S Online Beta Test | TLES-82043 | February 14, 2006 4:09:31 AM |
| ? | Marugoto Metal Gear Online | SLPM-68524 | |
| ? | Metal Gear & Metal Gear 2 | SLPM-66795 | |
| 9CE13145 | MPO | ULJM-05193 | October 15, 2006 7:22:04 AM |
| 9CE13145 | MPO | ULUS-10202 | October 15, 2006 7:22:04 AM |
| CD455D45 | MPO | ULES-00645 | November 17, 2006 5:17:01 AM |
| D6498A46 | MPO+ | ULJM-05261 | July 3, 2007 1:06:30 PM |
| D6498A46 | MPO+ | ULUS-10290 | July 3, 2007 1:06:30 PM |
| D6498A46 | MPO+ | ULES-01003 | July 3, 2007 1:06:30 PM |
| ? | MGS4 Guns of the Patriots | BLJM-67001 | |
| 5E1AE247 | MGS4 Guns of the Patriots | BLUS-30109 | March 20, 2008 8:03:42 AM |
| 5E1AE247 | MGS4 Guns of the Patriots | BLES-00246 | March 20, 2008 8:03:42 AM |
| 5E1AE247 | MGS4 v2.00 | BLES-00246 v2.00 patch | March 20, 2008 8:03:42 AM |
| 56ECBC47 | MGO2 Premier Beta | NPJB-90090 | February 21, 2008 3:13:26 AM |
| 591AD947 | MGO2 Premier Beta | NPJB-90090 | March 13, 2008 12:13:13 PM |
| ? | MGO2 Premier Beta | NPUB-90086 | |
| ? | MGO2 Premier Beta | BLET-70000 | |
| BC953449 | MGO2 Demo | NPEB-90122 | December 2, 2008 1:56:12 AM |
| ? | MGO2 | too many updates | ??? |
| E1F43B48 | MGS4 Database | NPUB-90126 or NPEB-00027 | May 27, 2008 11:47:45 AM |
| 638EDB48 | MGS4 Demo Version | NPUB-90176 | September 25, 2008 1:13:07 PM |
| 5DB1EA48 | MGS4 Demo Version | NPJB-90149 | October 7, 2008 12:46:21 AM |
| ? | MGS4 Demo Version | NPEB-90116 | |
| ? | MGS Peace Walker Demo Ops | NPJH-90063 | |
| ? | MGS Peace Walker Demo Ops | NPUH-90066 | |
| ? | MGS Peace Walker Demo Ops | NPEH-90023 | |
| 063B5D4B | MGS Peace Walker | NPJH-50045 | January 25, 2010 6:32:38 AM |
| 063B5D4B | MGS Peace Walker | ULUS-10509 | January 25, 2010 6:32:38 AM |
| ? | MGS Peace Walker | ULES-01372 | |
| FD42764C | Metal Gear Arcade | I36-2011012100 | August 26, 2010 10:33:33 AM |
| B5447C4C | Metal Gear Arcade | I36-2011092900 | August 30, 2010 11:54:29 PM |
| ? | MGS Peace Walker HD Edition | NPJB-00123 (etc) | |
| ? | MGS Peace Walker HD Edition | BLUS-30847 (etc) | |
| ? | MGS Peace Walker HD Edition | NPEB-00686 (etc) | |
| ED73E34E | MGS Snake Eater 3D | CTR-P-AMGJ | December 10, 2011 2:59:57 PM |
| 546DE74E | MGS Snake Eater 3D | CTR-P-AMGE | December 13, 2011 3:20:52 PM |
| 366EE74E | MGS Snake Eater 3D | CTR-P-AMGP | December 13, 2011 3:24:38 PM |
| 3100EA4E | MGS Snake Eater 3D Demo | CTR-T-AMGJ | December 15, 2011 2:12:01 PM |
| EF07EA4E | MGS Snake Eater 3D Demo | CTR-T-AMGP | December 15, 2011 2:45:03 PM |
| 820FEA4E | MGS Snake Eater 3D Demo | CTR-T-AMGE | December 15, 2011 3:17:22 PM |