确定if条件中使用的布尔表达式中哪个条件为真

Question

Suppose we have a simple boolean expression filled with boolean return type function calls with logical OR operators between them. This boolean expression is used only in a single if clause. For example:

if (c1() or c2() or c3()): #c1(), c2(), c3() are sample boolean return type methods
  foo1()
  foo2()
  print ("foo1() and foo2() have been executed because condition # <number> is true")

1. Is it possible to find out the method call (most basic unit of condition such as c2() is condition # 2) because of which the program entered the code inside the if clause without storing the return values of any of the method call or calling any method again?
2. Suppose c1() , c2() and c3() would have all returned true boolean values. However due to short-circuit boolean evaluation , c2() and c3() would never be executed. Can we somehow find it because of which conditions/method calls, the program might have still entered the code block inside the if clause while applying the same conditions mentioned in point number 1.

The answer can be in any programming language. I'm just curious to see if it is and how it is possible.

Answer 1

For some reason you tagged both on python and c# , the answer can be completly different in each language.

In c# I would have done it in the following pattern:

public ResultModel checkSomething()
{
    ResultModel retVal = new ResultModel();

    if(condition1)
    {
        retVal.DidSucceed = true;
        retVal.Source = eSource.Condition1;
    }
    else if (condiction2){
        ...
    }

    return retVal;
}

class ResultModel
{
    public bool DidSucceed {get;set;}
    public eSource Source {get;set;}
}

Answer 2

Here's how you can do this in Python,

condn = 0
for i, c in enumerate((c1(), c2(), c3()):
    if c:
        condn = i + 1
        break
if condn:
  foo1()
  foo2()
  print("condition number #{} is true".format(condn))

# if c2() is true, it prints
"condition number #2 is true"

Answer 3

you can do something tricky like this, but not the best solution

check = []
def c1():
    global check
    if True: check.append('c1')

Answer 4

第一个问题的答案是“否”，每当其中一个函数返回true ，if中的代码就会执行，并且如果没有调试器或将值存储在某个变量中就看不到值是什么。

Answer 5

To get this behaviour without polluting namespace with global variables or turning c* functions into classes I would implement it like this:

conditions = [c1, c2, c3]
for index, cond in enumerate(conditions):
    if cond():
        foo1()
        foo2()
        print(f"foo1() and foo2() have been executed because condition {index} is true")
        break

this basically hardcodes or behaviour, but other than that is fine.