elm-syntax-dsl

Provides a DSL that makes it simpler to write code in Elm that generates Elm code; simpler than stil4m/elm-syntax on which this DSL is based.

Simpler code generation as a DSL.

stil4m/elm-syntax uses a lot of records to capture parameters, and also wraps parts of the AST in Nodes that capture source code lines and rows corresponding to parts of the AST. This DSL inlines most of the records as function parameters.

stil4m/elm-syntax is spread across around 17 modules for the complete syntax. This makes working with it a little awkward because there are a lot of import statements to write. This DSL condenses everything into a single exposed module, which helps to get started with code generation more easily.

Any parts of the AST needing to be wrapped in nodes are automatically wrapped in nodes with zeroed out source code position information. As the purpose of this package is code generation of Elm from scratch, rather than the analysis or manipulation of existing Elm, it is ok to have the source code positional information zeroed out.

Pretty printing stable under elm-format.

The pretty printer aims to be fully stable with respect to elm-format in the sense that running elm-format on the output should have no effect at all. The advantage of this is that if generated code moves to being edited by hand, there will not be a large white-space only diff created when elm-format is applied.

Broken stuff in elm-syntax:

• Not all Elm files I tried seem to parse.
• Multi-line strings do something very weird and get jumbled up in order.
• End-line comments are deleted.

Known deviations from elm-format:

• Float literals not getting a .0 added at the end.
• Unicode characters.
• Type annotations on functions sometimes split onto next line without being broken themselves.