def gen_free_name(tree: ast.AST,
env: SymbolTable,
prefix: tp.Optional[str] = None) -> str:
names = used_names(tree) | env.keys()
if prefix is not None and prefix not in names:
return prefix
elif prefix is None:
prefix = '__auto_name_'
f_str = prefix + '{}'
c = 0
name = f_str.format(c)
while name in names:
c += 1
name = f_str.format(c)
return name
def gen_free_prefix(tree: ast.AST,
env: SymbolTable,
preprefix: tp.Optional[str] = None) -> str:
def check_prefix(prefix: str, used_names: tp.AbstractSet[str]) -> bool:
return not any(name.startswith(prefix) for name in used_names)
names = used_names(tree) | env.keys()
if preprefix is not None and check_prefix(preprefix, names):
return preprefix
elif preprefix is None:
preprefix = '__auto_prefix_'
f_str = preprefix + '{}'
c = 0
prefix = f_str.format(c)
while not check_prefix(prefix, names):
c += 1
prefix = f_str.format(c)
return prefix
def is_free_prefix(tree: ast.AST, env: SymbolTable, prefix: str):
names = used_names(tree)
return not any(
name.startswith(prefix) for name in itertools.chain(names, env.keys()))