Require fay code from nodejs

Question

Is it possible to require compiled modules from other simple server side javascript files in nodejs? It would be great. Maybe there is some option in the compiler for creating modules compatible with commonjs?

Answer 1

This is probably a bad idea, as it depends heavily on the features of the generated code.

Pay attention to the following points:

• Regardless of the name of the compiled module, fay is created in the main variable.
• In node.js, the return value from require is the modules.export module (which is originally the same object as export ), but it does not necessarily remain the same).
• A variable can be used before its definition is declared with var . The specified variable is the same. He doesn't care about anything to streamline the source code, and everything that happened at runtime.
• Fay by default (i.e. without --library ) can instantiate an object and execute main .

Remarkably, this means that in main we can change module.exports or exports to export the fay code. Of course, we should use ffi, but this is a fairly simple matter; the following, compiled without --library (which, yes, slightly contradicts intuition and really confirms the credibility of the hypothesis that this is an unpleasant hack, doesn't it) works to some extent:

 import FFI main :: Fay () main = ffi "module.exports = main" 

when require 'd from node, the returned object is a bit of an effect

 { 'Main$main': { forced: true, value: { value: [Circular] } }, _: [Function: Fay$$_], '$': [Function: Fay$$$], '$fayToJs': [Function: Fay$$fayToJs], '$jsToFay': [Function: Fay$$jsToFay] } 

With a working knowledge of Fay's internal representations, it is possible (although perhaps too much effort) to write a javascript wrapper for all thunk-forcing, etc.

(We could do more - in fact, with a bit more ffi work, we could write all the bindings as ffi code. It would be mildly stupid.)

Answer 2

You can use fay code from javascript, but at the moment it is a bit detailed, you need to use fully qualified names and manually call function calls.

 var m = new Main(); document.body.innerHTML = "The 10th fibonacci number is : " + m._(m.Main$fibN(9)); 

Currently everything is at the center of Main, we want to separate the compilation of each module so that each can be displayed separately. (then we can also switch to haskell-packages )

Then we need the ability to output a shell that does forcing and type of conversions for each module, so you don’t need this manually when calling from JavaScript.

Here are some related tickets: # 279 , 260