ComputerCraft - Gom - A Better Go Program For Turtles

-- An improved version of the go builtin command.
-- Accepts a sequence of commands of the form "[repetitionNumber]<action>" where the
-- repetitionNumber is optional and defaults to 1. Action can be
-- f -> forward, b --> backwards, l -> move one to the left, r -> ...
-- u -> up, d -> down
-- tl -> turn left, tr -> turn right

function terminate(errMsg)
    print(errMsg)
    os.sleep(5)
    os.queueEvent("terminate")
end


function execute(action, repetitionNumber)

    for i=1,repetitionNumber do
        if action == "f" then
            turtle.forward()
        elseif action == "b" then
            turtle.back()
        elseif action == "l" then
            if i == 1 then
                turtle.turnLeft()
            end
            turtle.forward()
            if i==repetitionNumber then
                turtle.turnRight()
            end
        elseif action == "r" then
            if i == 1 then
                turtle.turnRight()
            end
            turtle.forward()
            if i==repetitionNumber then
                turtle.turnLeft()
            end
        elseif action == "u" then
            turtle.up()
        elseif action == "d" then
            turtle.down()

        elseif action == "tl" then
            turtle.turnLeft()
        elseif action == "tr" then
            turtle.turnRight()

        else
            terminate(action .. " not a valid action. terminating...")
        end
    end
end

function split(command)
    local repetition = string.match(command, "%d*")
    if repetition == "" then
        repetition = 1
    end

    local action = string.match(command, "%a+")
    if action == "" then
        terminate(command .. " not a valid action. terminating...")
    end

    return tonumber(repetition), action
end

local args = {...}
for i, command in ipairs(args) do
    local repetitionNumber, action = split(command)
    execute(action, repetitionNumber)
end