✈️

Author: Iwan

.#README.md

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+[email protected].79594

.gitignore

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+.DS_Store
+node_modules/
+lib
+npm-debug.log
+.merlin

README.md

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+# Transit-js Bucklescript bindings #
+
+Make client-server communication great again.
+
+This repo provides rudimentary bindings to transit-js with Bucklescript,
+prototyped in under 15min. thanks to Bucklescript compiling at the speed of light.
+
+Json is nice, but I want to send records and variants among other things straight over
+the wire. Feels like a shame to lose all this information & type everything as js objects.
+Since transit provides a way to encode/decode custom data, it seemed like
+a good fit for encoding ml types. If this thing works out, remind me to automate the
+encoding/decoding with ppx.
+
+Head over to `src/example.re` to get up & running ASAP.

bsconfig.json

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+{
+    "name" : "transit-bs",
+    "sources" : { "dir" :  "src"},
+    "generate-merlin": true,
+}

package.json

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+{
+  "devDependencies": {
+    "bs-platform": "^1.4.1",
+    "transit-js": "^0.8.846"
+  },
+  "scripts": {
+    "build": "bsb",
+    "watch": "bsb -w"
+  }
+}

src/example.re

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+module Coordinate = {
+  type t = {x: int, y: int};
+  let make x y => {x, y};
+
+  /**
+   Transit read & write helpers
+   */
+  let writerSpec =
+    Transit.makeWriteHandler ({pub tag () => "coord"; pub rep {x, y} () => (x, y)} [@bs]);
+  let readerSpec (x, y) => {x, y};
+};
+
+module Size = {
+  type t = {width: int, height: int};
+  let make width height => {width, height};
+
+  /**
+   Transit read & write helpers
+   */
+  let writerSpec =
+    Transit.makeWriteHandler ({pub tag () => "size"; pub rep v () => (v.width, v.height)} [@bs]);
+  let readerSpec (width, height) => {width, height};
+};
+
+module Language = {
+  type t =
+    | Ocaml
+    | Lisp
+    | Other;
+
+  /**
+   Transit read & write helpers
+   */
+  let writerSpec = {
+    pub tag () => "lang";
+    pub rep v () =>
+      switch v {
+      | Ocaml => 0
+      | Lisp => 1
+      | Other => 3
+      }
+  };
+  let readerSpec rep =>
+    switch rep {
+    | 0 => Ocaml
+    | 1 => Lisp
+    | _ => Other
+    };
+};
+
+module Rectangle = {
+  type t = {origin: Coordinate.t, size: Size.t};
+  let make origin size => {origin, size};
+
+  /**
+   Transit read & write helpers
+   */
+  let writerSpec =
+    Transit.makeWriteHandler (
+      {pub tag () => "coord"; pub rep {origin, size} () => (origin, size)} [@bs]
+    );
+  let readerSpec (origin, size) => {origin, size};
+};
+
+let reader = Transit.reader {"handlers": {point: Coordinate.readerSpec, size: Size.writerSpec}};
+
+let writer =
+  Transit.writer @@
+  /*
+   In javascript this is a transit map from function constructors as keys to
+   writehandlers as values. Function constructors as keys only
+   matter if you have something like:
+   var Point = function(x, y) { this.x = x; this.y = y; };
+   (I think, need to investigate more)
+    */
+  Transit.map (
+    "Coordinate",
+    Coordinate.writerSpec,
+    "Size",
+    Size.writerSpec,
+    "Language",
+    Language.writerSpec,
+    "Rectangle",
+    Rectangle.writerSpec
+  );
+
+let encodedCoordinate = Transit.write writer (Coordinate.make 8 8);
+
+let encodedSize = Transit.write writer (Size.make 5 5);
+
+let encodedLanguage = Transit.write writer Language.Ocaml;
+
+let encodedRectangle =
+  Transit.write writer (Rectangle.make (Coordinate.make 0 0) (Size.make 10 10));
+
+let coordinate: Coordinate.t = Transit.read reader encodedCoordinate;
+
+let size: Size.t = Transit.read reader encodedSize;
+
+let lang: Language.t = Transit.read reader encodedLanguage;
+
+let rect: Rectangle.t = Transit.read reader encodedRectangle;
+
+let () =
+  Language.(
+    switch lang {
+    | Ocaml => print_endline "OCaml!!!"
+    | Lisp => print_endline "The most intelligent way to misuse a computer"
+    | _ => print_endline "other stuff"
+    }
+  );

src/transit.re

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+type reader;
+
+type format =
+  | Json
+  | JsonVerbose;
+
+let string_of_format t =>
+  switch t {
+  | Json => "json"
+  | JsonVerbose => "json-verbose"
+  };
+
+external raw_reader : string => 'options => reader =
+  "reader" [@@bs.val] [@@bs.module "transit-js"];
+
+let reader ::format=Json options => {
+  let readerType = string_of_format format;
+  raw_reader readerType options
+};
+
+external read : reader => 'a => 'b = "read" [@@bs.send];
+
+type writehandler;
+
+external makeWriteHandler : 'a => writehandler =
+  "makeWriteHandler" [@@bs.val] [@@bs.module "transit-js"];
+
+type writer;
+
+type transitMap;
+
+external map : 'handlers => transitMap = "map" [@@bs.val] [@@bs.module "transit-js"];
+
+external raw_writer : string => 'handler => writer =
+  "writer" [@@bs.val] [@@bs.module "transit-js"];
+
+let writer ::format=Json options => {
+  let writerType = string_of_format format;
+  raw_writer writerType {"handlers": options}
+};
+
+external write : writer => 'a => 'b = "write" [@@bs.send];

src/transit.rei

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+type format;
+
+type reader;
+
+let reader: format::format? => 'options => reader;
+
+type writer;
+
+external read : reader => 'a => 'b = "read" [@@bs.send];
+
+type writehandler;
+
+external makeWriteHandler : 'a => writehandler =
+  "makeWriteHandler" [@@bs.val] [@@bs.module "transit-js"];
+
+type transitMap;
+
+external map : 'handlers => transitMap = "map" [@@bs.val] [@@bs.module "transit-js"];
+
+let writer: format::format? => transitMap => writer;
+
+external write : writer => 'a => 'b = "write" [@@bs.send];