NMLTutorial
Since June 2010 a new coding language for creating TTDpatch/OpenTTD GRF's exists: the NewGRF Meta Language or NML for short. It differs significantly from the old way of writing NewGRFs in NFO and although documentation is available it may still be a challenge for people interested in using NML code. After all NML is still a form of programming language and not a GUI-based editor.
The NML tutorial aims at providing entry-level instructions and examples of how coding in NML works and hopefully inspires people who previously thought making a NewGRF themselves was impossible to give NML a whirl.
NML vs. NFO
Background
NML is a high-level NewGRF language compiler which compiles NML and LNG files into newgrf files (and NFO files, if asked to do so). Coding a NewGRF in NML is similar to writing in any other programming language except that there are no real sub-routines; you can use the usual definition and condition statements.
Language support
NML provides easy support for different languages in one GRF. This is achieved by creating language files (lng). These language files follow the convention used for OpenTTD translation files. When compiling NML files a search for language files will automatically be performed. Even without providing additional translations at least one language file must be specified, called default.lng.
Image format support
One of the conveniences of NML is the possibility to read various image formats. Remember though that those images still need to supply the proper 8bpp palette and are supported by the python image library.
Example
Does the above sound impressive, maybe even threatening to you? One illustration often says more than a thousand words so let's show the difference with two illustrations:
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NFO code snippet
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NML code snippet
NML language file snippet
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How to read the NML tutorial
The NML Tutorial starts with the installation of NML and continues from there as single "story" if you like. The bottom of each tutorial page has a link to the next page (and the previous in case you missed something) and all pages from the tutorial are also listed in navigation box at the top right of each page.
Example NML code is displayed in a code box and a blue font colour (much like the NML documentation itself). Code syntax definitions and other code and command (snippets) are displayed in black, either in a code box or in line with the text.
//example NML code
block {
//block definition
item: value;
}
If you have any questions about the text and examples within the NML tutorial, you are welcome to post those in the [link_to_be_added NML Tutorial topic] at TT-Forums. If you see bugs in the tutorial, you of course fix them or discuss them in the topic linked above first. Expanding or changing the tutorial should only be done by people who actually know NML and don't need this tutorial to code their NML files.
NML Tutorial: NMLTutorial
