在没有 exec/eval 的情况下调用字符串中的代码，python

Question

我有这样的代码，当玩家尝试吃东西时执行：

def eat(target='object'):
    global current_room
    global locations
    global inventory
    if target in inventory:
        items[target]['on_eat'] #This is showing no results.
    else:
        print 'You have no ' + target + ' to eat.'

以及 items(trimmed) 的这段代码

items = {
'strawberry': {
    'weight': 1,
    'text': 'The strawberry is red',
    'on_eat': "normal_eat('strawberry', 'pretty good, but not as sweet as you expected')"
    },
'trees': {
    'weight': 50,
    'text': 'The trees are tall with large, leaf filled branches blocking out a majority of sunlight.',
    'on_eat': "forcesay('Eating trees? What the hell is your problem?')"
    }
}

是否有一种有效的方法来调用 items[whatever]['on_eat'] 而不做像 exec() 或 eval() 这样的愚蠢的事情？如果没有，替代格式作为示例也将受到赞赏。

在此之前， items[everyitems]['on_eat'] 值不是字符串，而是在代码运行后立即为每个项目执行 on_eat 。

我见过很多类似问题的答案，但它们不处理独特函数的参数 - 更好地说，它们更像 这个

Answer 1

您可以将函数和函数参数存储为 partial：

from functools import partial

items = { 
'strawberry': { 
    'weight': 1, 
    'text': 'The strawberry is red', 
    'on_eat': partial(normal_eat, 'strawberry', 'pretty good, but not as sweet as you expected') 
    }, 
'trees': { 
    'weight': 50, 
    'text': 'The trees are tall with large, leaf filled branches blocking out a majority of sunlight.', 
    'on_eat': partial(forcesay, 'Eating trees? What the hell is your problem?')
    } 

def eat(target='object'):  
    # those globals are probably not necessary
    if target in inventory:  
        items[target]['on_eat']()  #Add ()'s to call the partial
    else:  
        print 'You have no ' + target + ' to eat.'

Answer 2

你可以使用代码模块

def eat(target='object'):
    import code
    console = code.InteractiveConsole(locals()) # make a python interpreter with local vars
    if target in inventory:
        console.push("items[target]['on_eat']")
    else:
        print 'You have no ' + target + ' to eat.'

Answer 3

部分函数的替代方法是编写这样的项目

items = {
'strawberry': {
    'weight': 1,
    'text': 'The strawberry is red',
    'on_eat': (normal_eat,('strawberry', 'pretty good, but not as sweet as you expected'))
    },
'trees': {
    'weight': 50,
    'text': 'The trees are tall with large, leaf filled branches blocking out a majority of sunlight.',
    'on_eat': (forcesay,('Eating trees? What the hell is your problem?',))
    }
}

并像这样调用它

def eat(target='object'):
    if target in inventory:
        func, args = items[target]['on_eat']
        func(*args)
    else:
        print 'You have no ' + target + ' to eat.'

您不需要那些 global 语句，除非您将重新分配它们