merits of Lisp vs Python

[Ken Tilton]

Bjoern Schliessmann wrote:
> Alex Mizrahi wrote:
> 
>>(message (Hello 'Bjoern)
> 
> 
>>> BS> Can you give an example? I cannot imagine how homogenity
>>> always BS> results in easiness.
> 
>  
> 
>>homogenity means that i can cut any expression and paste in any
>>other expression, and as long as lexical variables are ok, i'll
>>get correct results -- i don't have to reindent it or whatever.
> 
> 
> Ah, so *that's* what you meant ... but I don't really understand the
> ease of it.

Code in the abstract exists as a tree of trees. With parens, we now have 
textual markers delimiting these trees. That means I can point to any 
arbitrary subtree by pointing to its left or right parens, and tell the 
editor to copy or delete "that chunk of logic". And now I am 
manipulating chunks of program logic instead of text.

One simple but hopefully illustrative example: suppose I have an if 
statement with two big branches. My code then looks like:
   (if (condition) (big-branch-1)(big-branch-2))

Please remember that any of those fakes can be arbitrarily deep nested 
expressions. Now during refactoring, I decide bb-2 processing goes 
elsewhere, maybe somewhere "upstream" in the logic. So I double-click 
and then drag-and-drop, or cut and paste.

Then I double-click on the entire if statement, and then do a 
control-click on the "then" condition, control-click happening to mean 
"paste what I am clicking". Suddenly the "then" is the whole form.

(And, yes, this means my vendor took away from me the normal 
copy-and-drop associated with control click <g>, but I could modify 
things to get it back if I really cared.)

Of course the next question has to be, how often does that come up? When 
refactoring it sometimes feels like I do nothing else. :) It turns out 
that this is an insanely natural way to work with code.

Note also that after any amount of dicing I simply hit a magic key combo 
and the editor reindents everything. In a sense, Lisp is the language 
that handles indentation best.

hth, ken

-- 
Algebra: http://www.tilton-technology.com/LispNycAlgebra1.htm

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