blocks|key|4130066|text|我从这个answer中得到了灵感，以便详细阐述我的。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4130067|因此，我将使用inspect和re模块以及一个decorator来检查是否调用了run方法：|style|CODE|4130068|import+re
import+inspect

def+check_run_is_called(func):
++++def+wrapper(*args,+**kwargs):
++++++++#+Here+the+interesting+part
++++++++#+We're+searching+if+the+string+`.run()`+exists+in+the+code+context
++++++++run_exist+=+re.search(r'\.run$.*?$',+inspect.stack()[-1].code_context[0])
++++++++if+not+run_exist:
++++++++++++raise+Exception('Run+must+be+called+!')
++++++++f+=+func(*args,+**kwargs)
++++++++return+f
++++return+wrapper


class+TestClass():
++++@check_run_is_called
++++def+method1(self,+arg):
++++++++print(arg)
++++++++return+self

++++@check_run_is_called
++++def+method2(self,+arg):
++++++++print(arg)
++++++++return+self

++++@check_run_is_called
++++def+method3(self,+arg):
++++++++print(arg)
++++++++return+self

++++def+run(self):
++++++++print('Run')


#+test
if+__name__+==+'__main__':
++++app+=+TestClass()
++++app.method1('method1').method2('method2').method3('method3').run()|code-block|syntax|javascript|4130069|输出：|4130070|method1
method2
method3
Run|4130071|否则，如果我们调用方法链而不包含run方法：|4130072|app.method1('method1').method2('method2').method3('method3')|4130073|我们会得到一个Exception|4130074|Exception:+Run+must+be+called+!|4130075|除此之外，您还可以像下面这样创建链的组合：|4130076|app.method1('method1').run()
#+method1
#+Run
app.method1('method1').method2('method2').run()
#+method1
#+method2
#+Run
app.method2('method2').method3('method3').method1('method1').run()
#+method2
#+method3
#+method1
#+Run|4130077|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/8663885/3926995^0|4|6|0|0|7|7|F|2|N|9|14|3|0|0|0|0|G|3|0|0|7|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|E|5|6|7|1E|8|@$A|1F|B|1G|F|G]|$A|1H|B|1I|F|G]|$A|1J|B|1K|F|G]|$A|1L|B|1M|F|G]]|9|@]|C|$]]|$1|H|3|I|5|J|7|1N|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1O|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1P|8|@]|9|@]|C|$K|L]]|$1|Q|3|R|5|6|7|1Q|8|@$A|1R|B|1S|F|G]]|9|@]|C|$]]|$1|S|3|T|5|J|7|1T|8|@]|9|@]|C|$K|L]]|$1|U|3|V|5|6|7|1U|8|@$A|1V|B|1W|F|G]]|9|@]|C|$]]|$1|W|3|X|5|J|7|1X|8|@]|9|@]|C|$K|L]]|$1|Y|3|Z|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|10|3|11|5|J|7|1Z|8|@]|9|@]|C|$K|L]]|$1|12|3|-4|5|6|7|20|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]]]

I got inspired by this <a href="https://stackoverflow.com/a/8663885/3926995">answer</a> in order to elaborate mine.

So, i'll use <code>inspect</code> and <code>re</code> modules alongside with a <code>decorator</code> in order to check if <code>run</code> method is called or not:

<pre><code>import re
import inspect

def check_run_is_called(func):
 def wrapper(*args, **kwargs):
 # Here the interesting part
 # We're searching if the string `.run()` exists in the code context
 run_exist = re.search(r'\.run$.*?$', inspect.stack()[-1].code_context[0])
 if not run_exist:
 raise Exception('Run must be called !')
 f = func(*args, **kwargs)
 return f
 return wrapper


class TestClass():
 @check_run_is_called
 def method1(self, arg):
 print(arg)
 return self

 @check_run_is_called
 def method2(self, arg):
 print(arg)
 return self

 @check_run_is_called
 def method3(self, arg):
 print(arg)
 return self

 def run(self):
 print('Run')


# test
if __name__ == '__main__':
 app = TestClass()
 app.method1('method1').method2('method2').method3('method3').run()
</code></pre>

Output:

<pre><code>method1
method2
method3
Run
</code></pre>

Otherwise, if we call the method chain without including <code>run</code> method:

<pre><code>app.method1('method1').method2('method2').method3('method3')
</code></pre>

We'll get an <code>Exception</code>:

<pre><code>Exception: Run must be called !
</code></pre>

Besides of this, you can also create a combination of chains like this example:

<pre><code>app.method1('method1').run()
# method1
# Run
app.method1('method1').method2('method2').run()
# method1
# method2
# Run
app.method2('method2').method3('method3').method1('method1').run()
# method2
# method3
# method1
# Run
</code></pre>

blocks|key|4129581|text|你想要的是一个流畅的界面。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4129582|我将给你一个简单的例子，用某种装饰器可以使它变得更好|4129583|class+A:
++++def+__init__(self):
++++++++self.call_chain+=+[]

++++def+m1(self,+arg):
++++++++def+_actual_logic():
++++++++++++print(arg)
++++++++self.call_chain.append(actual_logic)
++++++++return+self

++++def+run(self):
++++++++for+f+in+self.call_chain:
++++++++++++f()

a+=+A().m1('snth')
a.run()|code-block|syntax|javascript|4129584|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

what you want is something like a fluent interface.

i'll give you a simple example, which could definitely be made better with some sort of decorator

<pre><code>class A:
 def __init__(self):
 self.call_chain = []

 def m1(self, arg):
 def _actual_logic():
 print(arg)
 self.call_chain.append(actual_logic)
 return self

 def run(self):
 for f in self.call_chain:
 f()

a = A().m1('snth')
a.run()
</code></pre>

I have a chain of methods in my python program of the <code>TestClass</code> object like below:-

<pre><code>TestClass().method1(args).method2(args).method3(args)
</code></pre>

I want to build a utility which will scan the above chain and then it can build an execution sequence. (similar to the way the data processing frameworks build their execution graph or dag). Also, the above sequence won't run until I call <code>run()</code> at the end.

so, in my case, it will run only when <code>run()</code> method is added to the end of the chain.

<pre><code>TestClass().method1(args).method2(args).method3(args).run()
</code></pre>

How to achieve this?

method chain lazy execution in python

我在TestClass对象的python程序中有一个方法链，如下所示：TestClass().method1(args).method2(args).method3(args)我想建立一个实用程序，它将扫描上述链，然后它可以建立一个执行序列。(类似于数据处理框架构建其执行图或dag的方式)。而且，直到我在最后调用run...

问python中的方法链惰性执行
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