def _check_For_stmt(stmt, env):
"""For Loop."""
assert stmt.__class__ is ast.For
x = stmt.target
e = stmt.iter
b0 = stmt.body
b1 = stmt.orelse
x_t = infer_expr(x, env)
# (For) assignment rule. -- restricted by type inference
return (x_t and check_expr(e, PType.list(x_t), env) and
check_stmt_list(b0, env) and check_stmt_list(b1, env))
def infer_List_expr(lst, env):
"""
Determine the type of AST `List` expression under type environment `env`.
`ast.List`
- `elts`: Python list of contained expr nodes
- `ctx': context of the expr (e.g., load, store)
"""
assert lst.__class__ is ast.List
elts_list = lst.elts
first_type = infer_expr(elts_list[0], env)
if all(check.check_expr(e, first_type, env) for e in elts_list[1:]):
# (lst) assignment rule.
return PType.list(first_type)
else:
# No assignment rule found.
return None
