Format¶
The configuration is written in YAML, a human-friendly textual data format. YAML is indentation sensitive, be sure to properly indent nested elements with 2 spaces.
We use the commons-configuration2 framework to process configuration, which supports variables, nesting, and lists.
Variables¶
Any existing configuration option can be used as a variable with the
${var} syntax, for example:
id: org.metaborg:org.metaborg.meta.lang.sdf:${metaborgVersion}
metaborgVersion: 2.0.0-SNAPSHOT
Here, the ${metaborgVersion} variable reference is replaced with
2.0.0-SNAPSHOT when reading the id configuration option. Note that
the order in which configuration options and variable references occur
does not matter.
The ${path:root} builtin property can be used to point to the root of
the language specification. Paths in the configuration must be absolute
unless stated otherwise. Use ${path:root}/ to make paths absolute,
relative to the project root, where required.
Furthermore, environment variables can be used through ${env:}, for
example ${env:PATH}. See the documentation on variable
interpolation
for more detailed informations on how variables work.
Nesting¶
Configuration options can be nested by nesting YAML objects, for example:
language:
sdf:
version: sdf2
results in the language.sdf.version option being set to sdf2, and
can be referenced with a variable using ${language.sdf.version}. The
same option can be set in the following way:
language.sdf.version: sdf2
Lists¶
Lists are supported using the YAML list syntax, for example:
dependencies:
compile:
- org.metaborg:org.metaborg.meta.lang.esv:${metaborgVersion}
- org.metaborg:org.metaborg.meta.lang.nabl:${metaborgVersion}
- org.metaborg:org.metaborg.meta.lang.test:${metaborgVersion}
results in the dependencies.compile option being set to a list with
elements:
org.metaborg:org.metaborg.meta.lang.esv:${metaborgVersion}org.metaborg:org.metaborg.meta.lang.nabl:${metaborgVersion}org.metaborg:org.metaborg.meta.lang.test:${metaborgVersion}
Created: October 17, 2024