The on-save handler (also known as the compiler strategy) is used to transform files when they are saved in an editor. In an IDE, when a new project is opened, the compiler strategy is also executed on each file in the project, as well as when files change in the background. In a command-line batch compiler setting, it is used to transform all files.
The compiler strategy is configured in an ESV file with the
on save key:
language on save : $Strategy
The identifier after the colon refers to the Stratego strategy that performs the transformation. This strategy must have the exact same signature as the one for actions.
language on save : compile-file