Monthly Start Lines

//version=5
indicator("Monthly Start Lines", overlay=true)

// Detect the first bar of a new month
is_new_month = (month != month[1])

// Draw vertical lines on the first bar of a new month
if is_new_month
line.new(x1=bar_index, y1=high + 100, x2=bar_index, y2=low - 100, color=color.new(color.white, 80), width=1, extend=extend.none)