Compiler from OCaml to Javascript.
OTHER License
Js_of_ocaml is a compiler from OCaml bytecode to JavaScript. It makes it possible to run pure OCaml programs in JavaScript environment like browsers and Node.js.
Js_of_ocaml is composed of multiple packages:
See opam file for version constraints.
opam install js_of_ocaml js_of_ocaml-compiler js_of_ocaml-ppx
Your program must first be compiled using the OCaml bytecode compiler ocamlc
.
JavaScript bindings are provided by the js_of_ocaml
package. The syntax
extension is provided by js_of_ocaml-ppx
package.
ocamlfind ocamlc -package js_of_ocaml -package js_of_ocaml-ppx -linkpkg -o cubes.byte cubes.ml
Then, run the js_of_ocaml
compiler to produce JavaScript code:
js_of_ocaml cubes.byte
Most of the OCaml standard library is supported. However,
Extra libraries distributed with OCaml (such as Thread) are not supported in general. However,
Tail call is not optimized in general. However, mutually recursive functions are optimized:
Effect handlers are supported with the --enable=effects
flag.
Data representation differs from the usual one. Most notably, integers are 32 bits (rather than 31 bits or 63 bits), which is their natural size in JavaScript, and floats are not boxed. As a consequence, marshalling, polymorphic comparison, and hashing functions can yield results different from usual:
OCaml | javascript |
---|---|
int | number (32bit int) |
int32 | number (32bit int) |
nativeint | number (32bit int) |
int64 | Object (MlInt64) |
float | number |
string | string or object (MlBytes) |
bytes | object (MlBytes) |
"immediate" (e.g. true, false, None, ()) | number (32bit int) |
"block" | array with tag as first element (e.g. C(1,2) => [tag,1,2] ) |
array | block with tag 0 (e.g. [|1;2|] => [0,1,2] ) |
tuple | block with tag 0 (e.g. (1,2) => [0,1,2] ) |
record | block (e.g. {x=1;y=2} => [0,1,2] ) |
constructor with arguments | block (e.g. C (1, 2) => [tag,1,2] ) |
module | block |
exception and extensible variant | block or immediate |
function | function |
Filename | Description |
---|---|
LICENSE | license and copyright notice |
README | this file |
compiler/ | compiler |
examples/ | small examples |
lib/ | library for interfacing with JavaScript APIs |
ppx/ | ppx syntax extensions |
runtime/ | runtime system |
toplevel/ | web-based OCaml toplevel |