Variables

[Richard Blackwood]

Bengt Richter wrote:

>On Sat, 23 Apr 2005 22:45:14 -0400, Richard Blackwood <richardblackwood at cloudthunder.com> wrote:
>
>  
>
>>Robert Kern wrote:
>>
>>    
>>
>>>Richard Blackwood wrote:
>>>
>>>      
>>>
>>>>To All:
>>>>
>>>>   Folks, I need your help. I have a friend who claims that if I write:
>>>>
>>>>foo = 5
>>>>
>>>>then foo is NOT a variable, necessarily. If you guys can define for 
>>>>me what a variable is and what qualifications you have to back you, I 
>>>>can pass this along to, hopefully, convince him that foo is indeed a 
>>>>variable.
>>>>        
>>>>
>>>None of us can do that unless you tell us what he thinks the word 
>>>"variable" means. The terminology is a bit fluid. I suspect that your 
>>>friend applying a somewhat restricted notion of "variable" that 
>>>coincides with the behavior of variables in some other language.
>>>
>>>      
>>>
>>Indeed, this language is math. My friend says that foo is a constant and 
>>necessarily not a variable. If I had written foo = raw_input(), he would 
>>say that foo is a variable. Which is perfectly fine except that he 
>>insists that since programming came from math, the concept of variable 
>>is necessarily the identical. This can not be true. For example, I may 
>>define foo as being a dictionary, but I can not do this within math 
>>because there is no concept of dictionaries within mathematics; yet foo 
>>is a variable, a name bound to a value which can change.
>>    
>>
>
>Maybe he doesn't know that foo = 5 in Python is not an equation as in math,
>but a Python source language statement to be translated to a step in some
>processing sequence.
>
>Tell him in Python foo is a member of one set and 5 is a member of another,
>and foo = 5 expresses the step of putting them into correspondence
>to define a mapping, not declaring them equal.
>  
>
Could I honestly argue this to him? From what basis do I argue that it 
is not an equation? In any event, he would likely (passionately) 
disagree considering his notion that programming is an off-shoot of math 
and thus at the fundamental level has identical concepts and rules. 
Believe it or not, he used to be a programmer. Back in the day (while I 
was getting my PhD in philosophy), he was a employed programmer using 
Cobol, Fortran, and other languages like that. Did his seemingly 
peculiar definition of variable exist at that time?

>Even in math notation, ISTM important to distinguish between
>a finger and what it may for the moment be pointing at.
>
>Regards,
>Bengt Richter
>  
>