Why is Python popular, while Lisp and Scheme aren't?

[Jay O'Connor]

In article <uso6sqgn3fmcb0 at corp.supernews.com>, "Cameron Laird"
<claird at lairds.com> wrote:

> In article <20021108.121940.201305624.9010 at cybermesa.com>, Jay O'Connor
> <joconnor at cybermesa.com> wrote:
>>In article <uso37rcegqdpf6 at corp.supernews.com>, "Cameron Laird"
>><claird at lairds.com> wrote:
>>
>>> In article <20021108.115059.1034949299.9010 at cybermesa.com>, Jay
>>> O'Connor <joconnor at cybermesa.com> wrote:
>>> 			.
>>> 			.
>>> 			.
>>>>Yes, I was a Python advocate in a TCL shop for awhile and had a hard
>>>>time convincing
>>>>people that there was a qualitative difference between.
>>>>
>>>>set x [lindex [lindex $var 5] 5]
>>>>
>>>>and
>>>>
>>>>x = var[5][5]
>>> 			.
>>> 			.
>>> 			.
>>> Tcl has definite problems that are close to what this example
>>> expresses.
>>>  Somebody's tilting the idiomatic playing field, though; the
>>>  experienced
>>> Tcl-ers I know would write
>>>   set x $var(5,5)
>>> rather than deal with the monstrosity above.
>>
>>Unfortunately the code I was dealing with was using lists of lists of
>>lists nested many, many levels deep with no documentation in the code as
>>to why '5' was a particular field.
>>
>>Try hundreds to thousands of lines of 'the monstrosity above'
> 			.
> 			.
> 			.
> You have my sympathy.  Are you making a subtle point that Tcl invites
> bad coding?  

No, I'm making the point that TCL is syntactically weaker at expressing
complex structures and this is a qualitative difference between the two
languages

Expanding beyond just getting a single value from a multidimensional list
is what happens when you start throwing in lrange for slicing and other
ways of unwrapping the structure.  TCL's approach of using 'functionName
$var1 var2' leads quite easily and naturally to such 'monstrosities' as a
natural consequence of the stucture of the language.   When you start
throwing in heterogenous structures, especially dealing with nested
arrays (dictionaries) , etc..the syntactical shortcut doesn't scale very
well to dealing with complex data.  (incidentally, your example does not
do the same thing.

set l1 "1 2 3"
set l2 "4 5 6"
set l3 [list $l1 $l2]
set x [lindex [lindex $l3 1] 1]
puts $x

results in '5'

using 'set x(1,1)
results in an error

> What you describe sounds like the moral equivalent of a
> Pythoneer writing
>   i = 0
>   while 1:
>       if i < 73:
> 	  break
>       i = i + 1
>       ...
> rather than
>   for i in range(limit):

If limit is a variable based on conditions within the loop, then your
first example is a valid way of expressing counting until a conditional
is  reached.  Or, under circumstances, the basic approach is valid and
would only be 'wrong' in the situation where the loop end was static.

-- 
Jay O'Connor
joconnor at cybermesa.com
http://www.r4h.org/r4hsoftware