functions running in list as parameter

April 9, 2023

I am making a library for creating text adventure games.

Here is my main.py code:

from txtadvlib import utils

utils.menu("Main Menu", ["play","about","quit"])
utils.getInput(prompt="user>",
               ifs=[
                 "1",
                 "2",
                 "3"
               ],
               thens=[
                 print(1),
                 print(2),
               ],
               catch="print('caught')"
              )

Here is the code I use for the library:

import os
import time
import random
import colorama
from datetime import date
from colorama import Fore

class utils:
  def menu(title,optionsArray,):
    print(title)
    cycles = 0
    for i in optionsArray:
      cycles += 1
      print(f"[{cycles}].{i}")
      
  def getInput(prompt, ifs, thens, catch):
    choice = input(prompt)
    for i in ifs:
      if choice == i:
        eval(thens[ifs.index(i)])
        break
      else:
        eval(catch)

I do not want to be using eval for every function as it requires the library user to format any functions as strings.

Here is the problem:
the functions in the thens list run immediately and then the input goes.

Here is the output:

Main Menu
[1].play
[2].about
[3].quit
1    <--- function in the list ran
2    <--- function in the list ran
user>   <--- input prompt

I have tried making the function parameters one line, and I can’t think of anything else to try.

>Solution :

You could expect the library user to pass in a callable, which will be called in case this option is selected:

...
import functools 

def catch():
  print('caught')

utils.getInput(prompt="user>",
               ifs=[
                 "1",
                 "2",
                 "3"
               ],
               thens=[
                 lambda: print(1),
                 functools.partial(print, 2),
               ],
               catch=catch
              )

Then you code should look sth like this:

...
  def getInput(prompt, ifs, thens, catch):
    choice = input(prompt)
    for i in ifs:
      if choice == i:
        thens[ifs.index(i)]()
        break
      else:
        catch()