Attempt at Diamond Kata in Pony

diamond.pony

actor Main

    new create(env: Env) =>
        try 
            let size: U8 = env.args(1)?.u8()?
            let diamond = Diamond(size)?
            env.out.print(diamond.render())
        end


class Diamond
    //let _halfLevels:U8
    var _result:String = ""
    
    new create(size:U8)? =>
        if size == 0 then error end

        let halfLevels = size
        let width = halfLevels

        if halfLevels == 1 then
            _result = "A"
            return
        end
        
        var i:U8 = 0
        while i < halfLevels do
            _result.append(_spaces(i))
            _result.append("B").append("\n")
            i = i + 1
        end

        
    fun render():String =>
        _result
    
    fun _spaces(number:U8):String =>
        var spaces = String(number.usize())
        var i:U8 = 0
        while i < number do
            spaces.append("_")
            i = i + 1
        end

        spaces