问thinkscript if函数在重要情况下无用

EN

# Get the current offset from the right edge from BarNumber()
# BarNumber(): The current bar number. On a chart, we can see that the number increases
# from left 1 to number of bars e.g. 140 at the right edge.
def barNumber = BarNumber();
def barCount = HighestAll(barNumber);
# rightOffset: 0 at the right edge, i.e. at the rightmost bar,
# increasing from right to left.
def rightOffset = barCount - barNumber;

# This script gets the minimum value from data in the offset range between startIndex
# and endIndex. It serves as a functional but not direct replacement for the
# GetMinValueOffset function where a dynamic range is required. Expect it to be slow.
script getMinValueBetween {
    input data = low;
    input startIndex = 0;
    input endIndex = 0;
    plot minValue = fold index = startIndex to endIndex with minRunning = Double.POSITIVE_INFINITY do Min(GetValue(data, index), minRunning);
}

# Call this only once at the last bar.
script buildConditions {
    input startIndex = 1;
    input endIndex = -1;
# Since endIndex < startIndex, getMinValueBetween() should never
# be executed. However it is executed nevertheless.
    plot minValue = if (endIndex > startIndex) then getMinValueBetween(low, startIndex, endIndex) else close[startIndex];
}
plot scan;
if (rightOffset == 0) {
    scan = buildConditions();
} else {
    scan = 0;
}
declare lower;