I sing the praises of lambda, my friend and savior!

[Frohnhofer, James]

While I can't confirm your figures, I couldn't agree with your conclusions
more.  Simply put, lambda is intention revealing in a way that a function def
cannot be.  Further, the greatest cost savings is in program maintenance,
where lambda guarantees that a change I make will be local.

> -----Original Message-----
> From: python-list-bounces+james.frohnhofer=csfb.com at python.org
> [mailto:python-list-bounces+james.frohnhofer=csfb.com at python.org]On
> Behalf Of Clark C. Evans
> Sent: Wednesday, October 13, 2004 3:09 PM
> To: Jeff Shannon
> Cc: python-list at python.org
> Subject: Re: I sing the praises of lambda, my friend and savior!
> 
> 
> On Wed, Oct 13, 2004 at 10:47:56AM -0700, Jeff Shannon wrote:
> | Except that the Python philosophy is that overall, the 
> greatest clarity 
> | is achieved by having a single obvious way to do things.
> 
> When doing coding that uses alot of callbacks, use of lambda for
> tiny, nameless, single-use expressions is the "single obvious way to
> do something".
> 
> Assume for a moment the following programming costs:
> 
>   2m  Minting a name, that is, finding a name that is not 'foo'
>       which semantically adds to the readability and maintainability
>       of the code.
>         
>   30s Verifying that a function name is not used more than once to 
>       verify that changing its definition, or if it is reused, 
>       making sure all the places where a change would affect is OK.
> 
> In one of my files, I've got 20 or so lambdas, typically only a few
> characters to plug-in a computation.  You're asking me to pay a 40
> minute price just to mint names in this file?  Then, I've had, over
> the past year about 20 edits on that file, some of which change a
> few of these lambdas, say 2 changes per edit on average.  That's
> another 20 minutes.  So, over the last year, in this one file alone,
> not having lambdas would have cost me an additional hour of time!
> I've got 2 largish projects, each averaging about 20 files, so
> that's about 40 hours of time chewed up with small efficiency hits.
> Or, about $4,000 of billable time.   I'd rather keep the money or
> take a vacation, thank you very much.
> 
> I use Python beacuse it is a horribly efficient language for me to
> write software with; it is efficient beacuse I have the flexibiltiy
> to use several different constructs depending on which is more
> clearly expresses the intent of the developer. While lambda is a
> small part of this effiency, it is a factor.  It clearly expresses a
> simple, nameless single chunk of code that is never reused.
> 
> Propose another construct that has these features, and I'll gladly
> use it instead of lambda.
> 
> Best,
> 
> Clark
> -- 
> http://mail.python.org/mailman/listinfo/python-list
> 

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