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Module Ppx_driver

Signature

val add_arg : Arg.key -> Arg.spec -> doc:string -> unit

Add one argument to the command line

val register_transformation : ?extensions:Ppx_core.Std.Extension.V2.t list -> ?impl:(Parsetree.structure -> Parsetree.structure) -> ?intf:(Parsetree.signature -> Parsetree.signature) -> string -> unit

register_transformation name registers a code transformation.

name is a logical name for the transformation (such as sexp_conv or bin_prot). It is mostly used for debugging purposes.

extensions is a list of context independant extension point expanders. This is what most code transformation should use. Extension expanders from all registered transformations are applied at the same time, before any other transformations. Moreover they are applied in a top-down manner, for the following reason:

  • some extensions capture a pretty-print of the payload in their expansion and using top-down ensures that the payload is as close as possible to the original code
  • some extensions process other extension in a special way inside their payload. For instance %here (from ppx_here) will normally expand to a record of type Lexing.position. However when used inside %sexp (from ppx_sexp_value) it will expand to the human-readable sexp representation of a source code position.

impl is an optional function that is applied on implementation files and intf is an optional function that is applied on interface files. These two functions are applied on the AST of the whole file. They should only be used in specific cases:

1. the transformation needs to add an header and/or footer 2. the transformation expands extension points that depend on the context

val register_code_transformation : name:string -> impl:(Parsetree.structure -> Parsetree.structure) -> intf:(Parsetree.signature -> Parsetree.signature) -> unit

Same as:


      register_transformation
        ~name
        ~impl
        ~intf
        ()
val standalone : unit -> unit

Suitable for -pp and also usable as a standalone command line tool.

If the first command line argument is -as-ppx then it will run as a ppx rewriter.

val run_as_ppx_rewriter : unit -> unit

Suitable for -ppx. Used only for the public release.