transformations.py 文件源码

def cleanupSlices(a):
    """Remove any slice shenanigans, because Python lets you include unneccessary values"""
    if not isinstance(a, ast.AST):
        return a
    if type(a) == ast.Subscript:
        if type(a.slice) == ast.Slice:
            # Lower defaults to 0
            if a.slice.lower != None and type(a.slice.lower) == ast.Num and a.slice.lower.n == 0:
                a.slice.lower = None
            # Upper defaults to len(value)
            if a.slice.upper != None and type(a.slice.upper) == ast.Call and \
                type(a.slice.upper.func) == ast.Name and a.slice.upper.func.id == "len":
                if compareASTs(a.value, a.slice.upper.args[0], checkEquality=True) == 0:
                    a.slice.upper = None
            # Step defaults to 1
            if a.slice.step != None and type(a.slice.step) == ast.Num and a.slice.step.n == 1:
                a.slice.step = None
    return applyToChildren(a, cleanupSlices)