将Pine脚本转换为MQL4语言(简易指示器)

//@version=4
study("Simple Moving Average", shorttitle="SMA", overlay=true)
length = input(20, minval=1)
src = close
sma = sma(src, length)
plot(sma)

#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 Blue

double smaBuffer[];

int OnInit() {
    SetIndexBuffer(0, smaBuffer);
    SetIndexStyle(0, DRAW_LINE);
    SetIndexLabel(0, "SMA");
    return(INIT_SUCCEEDED);
}

int OnCalculate(const int rates_total, const int prev_calculated, const datetime &time[], const double &open[], const double &high[], const double &low[], const double &close[], const long &tick_volume[], const long &volume[], const int &spread[]) {
    int limit = MathMin(rates_total - prev_calculated, Bars - 1);
    for (int i = 0; i < limit; i++) {
        smaBuffer[i] = iMA(NULL, 0, 20, 0, MODE_SMA, PRICE_CLOSE, i);
    }
    return(rates_total);
}