NML:Getting started

NewGRF Meta Language

Preface

Getting started

Graphics files

Blocks

Units

Expressions

Elementary values

Builtin functions

Language files

Lists of props, vars and CBs

Warnings

Additional references

NewGRF compatibility

Deprecated syntax

Changes from NML 0.2 to 0.3

Changes from NML 0.3 to 0.4

Changes from NML 0.4 to 0.5

Vehicles, Stations, Canals, Bridges, Towns, Houses, Industries (Tiles), Cargos, Airports+Tiles, Objects, Railtypes, Roadtypes, Tramtypes, Terrain

NML Tutorial

Getting started

No subpages in this chapter.

NML is a a python-based compiler, capable to compile NML files (along with their associated language, sound and graphic files) into grf and / or nfo files. Windows users can install the windows binary which contains a binary which bundles all required libraries. Users on other OS need to install them separately, best by means of their packet manager. In order to work, the following items are required:

• python
  • any version from 2.5 through 2.7 will do, but not 3.x
  • downloadable from from http://www.python.org/)
  • Advise for windows users: apparently you can prevent a lot of problems by installing the 32bit version of python, even if you have a 64bit windows installation. Installing PIL might be troublesome if you do install the 64bit version of python.
• python image library
  • downloadable from http://www.pythonware.com/products/pil/
• ply
  • downloadable from http://www.dabeaz.com/ply/
• NML itself
  • the latest (nightly) build can be downloaded from http://bundles.openttdcoop.org/nml/nightlies/LATEST/

If you don't install these with the packet manager of your choice (or there is none like on windows and you don't use the pre-compiled binary file), you should install these libraries as well as NML itself using python setup.py install from your command prompt.

To verify that everything is installed, enter nmlc --version in your command line. This should output the version of NML as well as the version of the installed libraries.

Examples for small NML "projects" are found in the examples and regression folder of NML. Generally it's assumed that the language files are in a separate language folder lang, thus a simple project may look like this:

mynewgrf.nml
graphics.png
funny_sound.wav

lang/english.lng

The compiler itself nmlc is a command line tool and can take a number of parameters, at least the nml filename which it shall process, e.g. nmlc mynewgrf.nml will compile your nml file into the grf-file mynewgrf.grf.

The full syntax is:

Usage: nmlc [options] <filename>
Where <filename> is the nml file to parse

Options:
  --version             show program's version number and exit
  -h, --help            show this help message and exit
  -d, --debug           write the AST to stdout
  -s, --stack           Dump stack when an error occurs
  --grf=<file>          write the resulting grf to <file>
  --nfo=<file>          write nfo output to <file>
  -c                    crop extraneous transparent blue from real sprites
  -u                    save uncompressed data in the grf file
  --nml=<file>          write optimized nml to <file>
  -o <file>, --output=<file>
                        write output(nfo/grf) to <file>
  -t <file>, --custom-tags=<file>
                        Load custom tags from <file> [default:
                        custom_tags.txt]
  -l <dir>, --lang-dir=<dir>
                        Load language files from directory <dir> [default:
                        lang]