[RFC] Executors - the SimpleEval equivalent of exec()

[zhudotexe]

Note: This PR includes the changes in #62, #63, and #64.

I'd like to hear any comments on the idea of extending SimpleEval to execute a full body of statements, akin to py3's exec() function! This draft PR includes an implementation (starting on L746) that builds off of my changes in #63 of SimpleExecutor.execute(expression).

Additionally, I implemented multi-line statements and control flow (if, for, while, break, etc) in ExecutorWithControl.

Let me know if this sounds like something that's out of this library's scope, or if I should write up some test cases for executors!

Here's some examples of executors in action:

If-else

>>> import simpleeval
>>> e = simpleeval.ExecutorWithControl(functions={'range': range, 'print': print})
>>> expr = """
... if 1 < 0:
...     print("true")
... else:
...     print("false")
... """.strip()
>>> e.execute(expr)
false

For

>>> import simpleeval
>>> e = simpleeval.ExecutorWithControl(functions={'range': range, 'print': print})
>>> expr = """
... for i in range(5):
...     print(i)
... print(i)
... """.strip()
>>> e.execute(expr)
0
1
2
3
4
4

Nested control

>>> import simpleeval
>>> e = simpleeval.ExecutorWithControl(functions={'range': range, 'print': print})
>>> expr = """
... for i in range(5):
...     if i < 2:
...         print(f"{i} < 2")
...     elif i == 2:
...         print(f"{i} == 2")
...     else:
...         print(f"{i} > 2")
... """.strip()
>>> e.execute(expr)
0 < 2
1 < 2
2 == 2
3 > 2
4 > 2

Keyword control

>>> import simpleeval
>>> e = simpleeval.ExecutorWithControl(functions={'range': range, 'print': print})
>>> expr = """
... for i in range(5):
...     if i == 2:
...         break
... 
... return i
... """.strip()
>>> e.execute(expr)
2

[pep8speaks]

Hello @mommothazaz123! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file simpleeval.py:

Line 366:80: E501 line too long (82 > 79 characters)
Line 368:80: E501 line too long (103 > 79 characters)
Line 610:80: E501 line too long (97 > 79 characters)
Line 611:80: E501 line too long (109 > 79 characters)
Line 612:80: E501 line too long (81 > 79 characters)
Line 626:80: E501 line too long (82 > 79 characters)
Line 680:80: E501 line too long (86 > 79 characters)
Line 684:80: E501 line too long (101 > 79 characters)
Line 707:80: E501 line too long (86 > 79 characters)
Line 726:80: E501 line too long (103 > 79 characters)
Line 736:80: E501 line too long (112 > 79 characters)
Line 738:80: E501 line too long (119 > 79 characters)
Line 752:80: E501 line too long (101 > 79 characters)
Line 784:80: E501 line too long (85 > 79 characters)
Line 801:80: E501 line too long (105 > 79 characters)
Line 803:80: E501 line too long (106 > 79 characters)
Line 806:80: E501 line too long (93 > 79 characters)
Line 838:80: E501 line too long (112 > 79 characters)

• In the file test_simpleeval.py:

Line 16:80: E501 line too long (110 > 79 characters)
Line 17:80: E501 line too long (83 > 79 characters)
Line 597:45: E231 missing whitespace after ':'
Line 597:50: E231 missing whitespace after ':'
Line 597:55: E231 missing whitespace after ':'
Line 602:59: E231 missing whitespace after ':'
Line 602:64: E231 missing whitespace after ':'
Line 602:69: E231 missing whitespace after ':'
Line 605:66: E231 missing whitespace after ','
Line 607:68: E231 missing whitespace after ':'
Line 607:73: E231 missing whitespace after ':'
Line 622:53: E231 missing whitespace after ':'
Line 622:58: E231 missing whitespace after ':'
Line 627:68: E231 missing whitespace after ':'
Line 627:73: E231 missing whitespace after ':'
Line 656:80: E501 line too long (83 > 79 characters)
Line 823:80: E501 line too long (90 > 79 characters)
Line 858:23: E231 missing whitespace after ':'
Line 858:26: E231 missing whitespace after ':'

[coveralls]

Coverage decreased (-4.6%) to 95.094% when pulling ed11c10 on mommothazaz123:executors into b47858d on danthedeckie:master.

[coveralls]

Coverage decreased (-4.6%) to 95.114% when pulling ed11c10 on mommothazaz123:executors into b47858d on danthedeckie:master.