Parser for simplest S-expression or array-expression of parentheses by using 1-character input in Python

sread-c1.py

from sys import stdin

LH = False
def get_token():
    def put_c1(x): global LH; LH = x
    def null_c1(): global LH; LH = False
    def get_c1():
        if not LH:
            try: return stdin.read(1)
            except EOFError: pass
        else: lh = LH; null_c1(); return lh
    def tstring(t): return ''.join(t)
    def skip_spaces():
        c = get_c1();
        while c in ' \n\r\x1a': c = get_c1()
        put_c1(c)
    c = get_c1(); t = []
    while True:
        if c in ' \n\r\x1a':
            skip_spaces();
            if not t: c = get_c1()
            else: return tstring(t)
        elif c == '(': skip_spaces(); return c
        elif c == ')':
            if not t: return c
            else: put_c1(c); return tstring(t)
        else: t = t + [c]; c = get_c1()

def sread():
    def slist():
        t = get_token()
        if   t == ')': return []
        elif t == '(': h = slist(); return [h] + slist()
        else: return [t] + slist();
    t = get_token()
    return slist() if t == '(' else t

print(sread())