local ds = require("DataStructures")
local Dictionary, Stack, WordInfo, Environment = ds.Dictionary, ds.Stack, ds.WordInfo, ds.Environment

local CoreHelpers = {}

function CoreHelpers.defineWord(dict: Dictionary, str: string, func: function(Environment, ...: any): any..., imm: boolean)
	local info = WordInfo:new(func, imm)
	dict:define(str, info)
end



function CoreHelpers.areNumbers(a: any, b: any): boolean
	return a is number and b is number
end

function CoreHelpers.getActiveDataStack(state: Environment): Stack
	return state.activeDataStack
end

function CoreHelpers.isNumber(token: string): boolean
	if tonumber(token) ~= nil then
		return true
	else
		return false
	end
end

function CoreHelpers.isWhitespace(chr: string): boolean
	return (chr == " " or
					chr == "\t" or
					chr == "\r" or
					chr == "\n" or
					chr == "\v" or
					chr == "\f")
end
function CoreHelpers.skipWhitespace(state: Environment)
	local chr = state.activeInputStream:readCurrentCharacter()
	while (CoreHelpers.isWhitespace(chr)) do
		chr = state.activeInputStream:advanceOffset()
	end
end

function CoreHelpers.popTwoOperands(state: Environment): any, any
	local stack = CoreHelpers.getActiveDataStack(state)
	local b: any = stack:pop()
	local a: any = stack:pop()
	return a, b
end


function CoreHelpers.parseToken(state: Environment): string
	local chr = state.activeInputStream:readCurrentCharacter()
	local token = ""
	while(not CoreHelpers.isWhitespace(chr)) do
		token = token..chr
		chr = state.activeInputStream:advanceOffset()
	end
	return token
end

function CoreHelpers.reset(env: Environment)
	env.instructionPointer.index = 0 -- will get incremented after this instruction
end

return CoreHelpers