Error-Msg Jeannie's charming, teasing ways

[Cameron Simpson]

On 23Feb2023 14:58, Hen Hanna <henhanna at gmail.com> wrote:
>Python's Error-Msg  genie  (Jeannie)  is cute and fickle...   She 
>sometimes teases me by not telling me what the VALUE of the   "int"  is
>                         ( "That's for me to know, and for you to find out!" )
>as in:
>                           TypeError: can only concatenate str (not 
>                           "int") to str

This is a runtime error< not a syntax error. Valid code using invalid 
values. It can only be seen at runtime.

>Other times, she (Jeannie)  gives me a helpful comment:
>ABCD (above and beyond... her job desc.)
>                              if (x=0):
>                                    ^^^
>SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '='?

Syntax error can be seen at compile time. Since Python's interpreted, 
the compilation step i usually implicit in trying to run things. But 
technically this happens before any of _your_ code runs.

The helpfulness of this warning is a _very_ recent upgrade, with Python 
3.11 I think, maybe 3.10.  The syntax errors used to be a lot less 
helpful.

>is there a Tool that can scan my code and tell me   such   (wink,wink)  
>type suggestions????

There are several type checking programs for Python, with mypy probably 
being the best known. I seem to recall seeing some mention of tools 
which will aid inferring types from partially types programmes, usually 
as an aid to completing the type annotations.

Cheers,
Cameron Simpson <cs at cskk.id.au>