2018-11-26 Reason Language Server codemod example

ExampleCodemod.re

open Parsetree;

open Codemod.Helpers;

let replaceErrors = (ctx, expr) =>
  expr
  ->mapExpr((mapper, expr) => {
      switch (expr.pexp_desc) {
      | Pexp_construct({txt: Longident.Lident("Student")} as lid, Some({pexp_desc: Pexp_tuple([name, age])})) =>
        let loc = Location.none
        Some([%expr Student({name: [%e name], age: [%e age]})])
      | _ => None
      };
    });

let modify = (ctx, structure) =>
{
  structure->strExpr((mapper, expr) =>
      expr->mapFnExpr((mapper, args, body) => {
         /* Format.printf("%a\n%!", Pprintast.expression, body);*/
          switch (ctx->getExprType(body)) {
          | Reference(Public({moduleName: "More-Tryit", modulePath: _, name: "person"} as s), _) =>
            Format.printf("\n\x1b[33m%s \x1b[34m%s\x1b[0m\n%!", s.moduleName, s.name);
            Some((args, replaceErrors(ctx, body)))
          | _ =>
            None
          };
        })
      ->Some
    );
};

switch (Sys.argv) {
  | [|_, root|] =>
    print_endline("Running on project: " ++ root);
    Codemod.run(
      root,
      (path, moduleName) => Filename.extension(path) == ".re",
      modify
    );
  | _ => ()
};

More.re

open Result;

type person =
  | Student(string, int)
  | Teacher
  | Admin;

let s1 = Student("Alexa", 0);

/*
 original code:
 let nonCollapsible = something => Student("wow", 9999);
 */
let nonCollapsible = something => Student({name: "wow", age: 9999});