js_internal_gen.js

var assert = require('assert')

function initArray(n){
    var res = new Array(n)
    for (var i = 0; i < n; ++i){
        res[i] = i
    }
    return res
}

function gen_normal(arity){
    if(arity === 0){
        return "unit -> 'a0"
    } else {
        return initArray(arity+1).map(x=>`'a${x}`).join(' -> ')
    }
}

function gen_bs(arity){
    if (arity === 0) {
        return "([`Arity_0], 'a0) fn"
    } else {
        return `([\`Arity_${arity} of ( ${initArray(arity).map(x=>`'a${x}`).join(" * ")} )], 'a${arity}) fn`
    }
}

function gen_bs_this(arity){
    assert.notEqual(arity,0)
    return `([\`Arity_${arity} of ( ${initArray(arity).map(x=>`'a${x}`).join(" * ")} )], 'a${arity} ) meth_callback`
}

function gen_bs_meth(arity){
    if(arity === 0){
        return `([\`Arity_0], 'a0) meth`
    }
    return `([\`Arity_${arity} of ( ${initArray(arity).map(x=>`'a${x}`).join(" * ")} )], 'a${arity}) meth`
}

function generate_mk(arity){
   return `external fn_mk${arity} : (${gen_normal(arity)}) -> (${gen_bs(arity)}) = "#fn_mk" "${arity}" `
}

function generate_call_back_mk(arity){

   var arity = arity + 1 
   return `external fn_method${arity} : (${gen_normal(arity)}) -> (${gen_bs_this(arity)}) = "#fn_method" "${arity}" `
}

function generate_run(arity){
    if(arity===0){
        return `external fn_run0 : (([\`Arity_0], 'a0) fn) ->  'a0  = "#fn_run" "0" `
    }

    return `external fn_run${arity} : (${gen_bs(arity)}) -> (${gen_normal(arity)} ) = "#fn_run" "${arity}" `
}

function generate_method_run(arity){
    if(arity === 0){
        return `external method_run0 : (([\`Arity_0], 'a0) meth) -> 'a0 = "#method_run" "0" `
    }
    return `external method_run${arity} : (${gen_bs_meth(arity)}) -> (${gen_normal(arity)} ) = "#method_run" "${arity}" `
}

var prelude = `
(* Generated by scripts/js_unsafe_gen.ml *)  
type (-'obj, +'a) meth_callback
type (-'arg, + 'result) meth
type (-'arg, + 'result) fn 
(** Js uncurried function *)
external (!)  : 'a t -> 'a = "#unsafe_downgrade"
external debugger : unit -> unit = "#debugger"
external raw_expr : string -> 'a = "#raw_expr"
external raw_stmt : string -> 'a = "#raw_stmt"
external raw_function: string ->  'a = "#raw_function"
external unsafe_downgrade : 'a t -> 'a = "#unsafe_downgrade"
`.split('\n')

function genAll(prefix){
    var arities = initArray(10)
    var code  = 
    `${prefix} ${Array.prototype.concat(
                prelude,
                arities.map(generate_mk),
                arities.map(generate_call_back_mk),
                arities.map(generate_run),
                arities.map(generate_method_run)).map(x=>" " + x).join('\n')}
end`        
        // console.log(arities, arities.map(x=>generate_call_back_mk(x)))
    return code
}

var fs = require('fs')
var path = require('path')

if(require.main === module){
    // fs.writeFileSync(path.join(__dirname, '..', 'jscomp', 'runtime', 'js_unsafe.ml'), genAll(), 'utf8')
    var jsMlFile = path.join(__dirname,'..','jscomp','runtime','js.ml')
    var jsMliFile = path.join(__dirname,'..','jscomp','runtime','js.mli')
    var replacement = genAll('module Internal = struct')

    var jsCode = fs.readFileSync(jsMlFile,'utf8')
    fs.writeFileSync(jsMlFile, jsCode.replace(/module Internal = struct([^])*?end/m, replacement),'utf8')

    jsCode = fs.readFileSync(jsMliFile,'utf8')
    fs.writeFileSync(jsMliFile, jsCode.replace(/module Internal : sig([^])*?end/m, genAll('module Internal : sig')),'utf8')
}