拆分空格分隔的字符串，忽略单引号内的空格

def split_string(input_string):
    result = []
    in_quotes = False
    start = 0

    for i in range(len(input_string)):
        if input_string[i] == "'":
            in_quotes = not in_quotes
        elif input_string[i] == ' ' and not in_quotes:
            result.append(input_string[start:i])
            start = i + 1

    result.append(input_string[start:])

    return result

# 示例用法
input_string = "hello world 'this is a test' foo bar"
output = split_string(input_string)
print(output)

['hello', 'world', "'this is a test'", 'foo', 'bar']