gcode.js

const EventEmitter = require('events')
class Gcode extends EventEmitter {}

function create() {
    var gcode = new Gcode()

    // state
    gcode.mode = 'G0'
    gcode.speeds = {
    	G0: 1200,
    	G1: 400
    }

    // local functions
    function getKeyValues(str) {
    	var kv = {}
        for (var i = 0; i < str.length; i++) {
            if (str[i].match('[A-Za-z]')) { // regex to match upper case letters
                var lastIndex = str.indexOf(' ', i)
                if (lastIndex < 0) {
                    lastIndex = str.length
                }
                var key = str[i].toUpperCase()
                kv[key] = parseFloat(str.slice(i + 1, lastIndex))
            }
        }
        return kv
    }

    function parseGcode(str){
    	var instruction = {
    		position: {},
    		hasMove: false,
    		speed: 0
    	}

    	kv = getKeyValues(str)
    	// track modality
    	if(kv.G == 0 | kv.G == 1){
    		gcode.mode = 'G' + kv.G.toString()
    	} else if (kv.G != null) {
    		// no arcs pls
    		console.log('unfriendly Gcode mode!', kv)
    	}

    	for(key in kv){
    		if(key.match('[A-EX-Z]')){
    			instruction.position[key] = kv[key]
    			instruction.hasMove = true
    		} else if (key.match('[F]')){
    			gcode.speeds[gcode.mode] = kv.F
    		}
    	}

    	instruction.speed = gcode.speeds[gcode.mode]
    	// and this for help later?
    	instruction.kv = kv

    	return instruction
    }

    // input functions
    gcode.lineIn = function(str) {
    	var instruction = parseGcode(str)
    	if (instruction.hasMove){
    		gcode.emit('newInstruction', instruction)
    	} else {
    		gcode.emit('modeChange', gcode.mode)
    	}
    }

    return gcode
}

module.exports = {
    create: create
}