Creating Function Name from List and providing Property to it Dynamically in Python

Question

I'm trying to create Recursive Descent Parser in Python. It takes input string from user at runtime

Example string :

str1="(id+id*id+id)$"

and based on predefined CFG

Example Grammar :

E->TE'
E'->+TE'|e
T->FT'
T'->*FT'|e
F->(E)|id

the input string is passed through recursive functions and if it matches, the result is printed as Success.

Example Functions :

#A pointer to scan input string character by chatacter
lookahead=str1[0]

##def E():
##    #print("E()")
##    T()
##    ED()
##    
##    if count==l-1:
##        if lookahead=='$':
##            print("Success")
##        else:
##            print("Error : Rejected !")
##            return
##    else:
##        pass

#Similarly, all the other functions are defined

def T():
    F()
 *remaining code for function*

def F():
 *remaining code for function*

id = identifier and e = epsilon

Now, I was able to parse it for this Static CFG, but when I stated modifying it for Dynamic CFG which a user can input along with the string, I encountered error with Name Allocation for the functions and their attributes.

#Names of Functions to be created which is Extracted from User Input CFG 
functionList=['E','ED','T','TD','F']
#Note: using ED to display E' for function name

#Code to create function with names from functionList
def function_builder(val):
    def function(val):
        print("fun_",val)
    return function

dynamic_functions = {}
k=0
for i in functionList:
    dynamic_functions[i] = function_builder(functionList[k])
    k+=1
dynamic_functions[functionList[0]](functionList[0])

So, if input is A->TA', the program should automatically create

def A(), def T(), def AD() and so on. Also, I want to add properties to all function once they are allocated their names, like...

def A():
    T()
    AD()
 *remaining code for function*

My question is how can I define function name from list and give property then after?

P.S.: I have searched stackoverflow for Dynamic Function Name Generation from List/variable but didn't find any answers that can help me.

Take a look at this link: https://stackoverflow.com/questions/5920120/how-to-define-a-function-from-a-string-using-python it might help. — Fletchy, Aug 16 '19 at 17:29
```functionList=['E', 'ED', 'T', 'TD', 'F']``` is my list, i tried creating function using exec like this ```exec("""def """+functionList[0]+"""():\n""" """ exec(x[0][0]+())\n""" """ exec(x[0][1]+())""")``` but when i try to call function using ```exec(functionList[0]+"""()""")``` it throws error ```TypeError: can only concatenate str (not "tuple") to str``` @Fletchy1995 — alan, Aug 17 '19 at 11:49
x=[['T', 'ED'], ['T', 'ED'], ['F', 'TD'], ['F', 'TD'], '(E)|id'] — alan, Aug 17 '19 at 11:58
Well, what you expected `exec(x[0][0]+())` to do? Anyway, I think you should reconsider trying to create functions from CFG dynamically, this looks like it will result in code that's very hard to read of reason about. — Nickolay, Aug 18 '19 at 16:08
Yes ! the ```exec(x[0][0]+'()')``` should create a code which is a function, which is to be executed later, but it looks like python isn't going to let me execute it. @Nickolay — alan, Aug 20 '19 at 07:50
You wrote `+()` instead of `+'()'` in a previous comment, though, which results in the "can't concatenate tuple" error. — Nickolay, Aug 20 '19 at 11:19
I did a mistake before, but even if with ```'()' or "()" or """() """``` it is showing the same error @Nickolay — alan, Aug 20 '19 at 14:23

Creating Function Name from List and providing Property to it Dynamically in Python

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