feature suggestion

Scott David Daniels Scott.Daniels at Acm.Org
Fri Dec 24 14:37:22 CET 2004


flexibal wrote:
> hi there.
> 
> i didnt know if i should post it at python-dev or here, so i'll start
> here. 

Good choice.  Python-dev is not a location for you to propose work for
other people to do for you.

> BASIC has the "OPTION EXPLICIT" feature that forces you to explicitly
> declare all variables, and i see no reason why python should have a
> similar mechanism.
What you are looking for is "pychecker" -- use google and find that;
you will be able to find many of the code problems you talk about
here.

> syntactic verification, at parsing time. for example:
> my-prog.py:
> -------------
> ##decl x
> ##decl y, z
> x = 5
> y = 6
> z = 8
> a = 6  ### causes and error

This is _not_ a syntax error, syntax can be checked locally, without
memory.  "a = 6" is not a syntax error because you can tell exactly
valid what form the statement has, and the form of every expression
in the statement.  "a = 6 5" _is_ a syntax error; there is no way to
interpret "6 6" as an expression, and there is no way to interpret 
"<statement> 6" as a statement.  So, even if your proposal were to
be implemented, it would probably be an "access to undeclared
identifier" error.


--Scott David Daniels
Scott.Daniels at Acm.Org



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