expandvars.py 文件源码

def pathhasvars(source):
    """Expand shell variables of form $var and ${var}.  Unknown variables
    are left unchanged."""
    global _varprog, _varprogb
    if isinstance(source, bytes):
        if b'$' not in source:
            return False
        if not _varprogb:
            import re
            #_varprogb = re.compile(br'\$(\w+|\{[^}]*\})', re.ASCII)
            _varprogb = re.compile(br'\$(\w+|\{[^}]*\})')
        search = _varprogb.search
        start = b'{'
        end = b'}'
    else:
        if '$' not in source:
            return False
        if not _varprog:
            import re
            #_varprog = re.compile(r'\$(\w+|\{[^}]*\})', re.ASCII)
            _varprog = re.compile(r'\$(\w+|\{[^}]*\})')
        search = _varprog.search
        start = '{'
        end = '}'
    i = 0
    m = search(source, i)
    return not (not m)