cml.js

var cml = {
    Buffer:function (n) {
        var buf = [];
        this.full=function() {
            return !(buf.length < n);
        }
        this.add=function(item){
            buf.push(item);
        }
        this.remove=function(item){
            return buf.shift();
        }
        this.size=function(){
            return buf.length;
        }
        return this;
    },
    Channel:function (buffer){
        this.recvq = [];
        this.sendq = [];
        this.buffer = buffer;
        // TODO: closed
        return this
    },
    RX:function (channel) {
        this.block=function (resume_recv,recv_state) {
            if(channel.buffer.size() > 0) {
                var val = channel.buffer.remove();
                return function() { return val };
            }
            var sendq = channel.sendq
            var pessimistic = function () {
                var recvq = channel.recvq;
                recvq.push([resume_recv, recv_state]);
            };
            while(true){
                if (sendq.length > 0) {
                    var val = sendq[0][0];
                    var resume_sender = sendq[0][1];
                    var state = sendq[0][2];
                    if (state[0] == "W") {
                        state[0] = "S";
                        sendq.shift();
                        resume_sender(function () { return true; });
                        return function() { return val };
                    } else {
                        sendq.shift();
                    }
                } else {
                    return pessimistic();
                }
            }
        }
        return this
    },
    TX:function (channel, value) {
        this.block=function (resume_send, send_state){
            var recvq = channel.recvq;
            while(true){
                if(recvq.length > 0) {
                    var resume_recv = recvq[0][0];
                    var state = recvq[0][1];
                    if (state[0] == "W") {
                        state[0] = "S";
                        recvq.shift();
                        resume_recv(function () { return value; });
                        return function() { return true };
                    } else {
                        recvq.shift();
                    }
                } else {
                    if(!channel.buffer.full()) {
                        channel.buffer.add(value);
                        return function() { return true };
                    } else {
                        var sendq = channel.sendq
                        sendq.push([value, resume_send, send_state]);
                        return false;
                    }
                }
            }
            
             
        }
        return this;
    },
    Select:function (events) {
        this.block=function (resume, state) {
            for(var i = 0; i < events.length; i++) {
                events[i].block(resume, state);
            }
        }
        return this;
    },
    Timeout:function (ms) {
        var waits = [];
        var done = false;
        this.block=function (resume, state) {
            if(done) {
                state[0] = "S";
                return resume(function () {return true;});
            } else {
                waits.push([resume, state]);
            }
        }
        setTimeout(function () {
            for(var i = 0; i < waits.length; i++) {
                if(waits[i][1][0] == "W") {
                    waits[i][1][0] = "S";
                    var resume = waits[i][0];
                    setTimeout(function () {
                        return resume(function () {return true;});
                    });
                }
            }
            waits = [];
        }, ms);
        return this
    },
    sync:function (event, callback) {
        var state = ["W"];
        var f = event.block(callback, state);
        if (f) {
            return callback(f);
        } 
    },
    go:function (f) {
        console.log(f);
        var waits = [];
        var iter = f();
        var result = iter.next();
        var step = function() {
            if(!result.done) {
                var state = ["W"];
                var f = result.value.block(
                    function (f) {
                        setTimeout(function () {
                            result = iter.next(f());
                            step();
                        }, 0);
                    },
                    state);
                if (f) {
                    result = iter.next(f());
                    return step();
                }
            } else {
                for(var i = 0; i<waits.length; i++) {
                    if(waits[i][1][0] == "W") {
                        waits[i][1][0] = "S";
                        var resume = waits[i][0];
                        setTimeout(function () {
                            resume(function () {return result.value;});
                        }, 0);
                    }
                }
            }
        }
        setTimeout(step, 0);
        return {block:function (resume, state) {
            if(!result.done) {
                waits.push([resume, state]);
            } else {
                state[0] = "S";
                return resume(function () {return result.value;});
            }
        }};
    }
}

console.log("foo");

var as = new cml.Channel(new cml.Buffer(0));
var bs = new cml.Channel(new cml.Buffer(0));


cml.go(function*(){
    yield new cml.Timeout(1000*Math.random());
    yield new cml.TX(as, "A");
})

cml.go(function*(){
    yield new cml.Timeout(1000*Math.random());
    yield new cml.TX(bs, "B");
})

var x = cml.go(function*(){
    var x = yield new cml.Select([new cml.RX(as),new cml.RX(bs)]);
    console.log(x);
    return 10;
})

cml.go(function*(){
    var w = yield x;
    console.log(w);
})