Do you know where your variables are? PerlMonks

### Re^6: Understanding the Schwartzian transform.

by choroba (Bishop)
 on Jul 22, 2013 at 16:05 UTC ( #1045686=note: print w/replies, xml ) Need Help??

Because in GRT, you just change the data so they can be sorted lexicographically as strings, while in Schwartzian transform, you create a structure. You can simplify both to map {} sort {} map {} list (in GRT, sort block can be omitted), their difference can be seen only if you give more details.
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ
• Comment on Re^6: Understanding the Schwartzian transform.

Replies are listed 'Best First'.
Re^7: Understanding the Schwartzian transform.
by Laurent_R (Canon) on Jul 22, 2013 at 18:07 UTC

Agreed, but: 1. the OP did not ask for the difference between Guttman-Rosler and Schwartzian transforms, but only if MJD's code he had was a canonical ST. And this example is a canonical ST, which it what I said. The fact that I somewhat summarized for brevity (and because it could be other code for a different probklem and still be a ST) does not invalidate my point and certainly does not make the OP's initial code nor the summary that I made a GR transform. As you said, a GR transform would have omitted the sort block. I reallyt think that the OP question was whether the standard ST consists of the map-sort-map construct.

Agreed ... OPs question

Yes, the original is canonical ST, there is no disputing that (you answered correctly)

But your shortening (somewhat summarized for brevity ) to  @out = map {} sort {} map {} @in is definitely not the canonical Schwartzian Transform

because the essence of ST is not the pipeline, pipeline is regular usage of map/grep, its even present in GRT. The essence of ST, the trick of it, the rule of it , [ is the caching ] .

If you replace the essence with  {BLOCK} its unrecognizable, might as well call it  transform / sort / transform -- nothing Schwartzian about it :) and not very descriptive, unlike decorate-sort-undecorate which describes both ST and GRT

Create A New User
Node Status?
node history
Node Type: note [id://1045686]
help
Chatterbox?
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others pondering the Monastery: (2)
As of 2018-04-25 21:15 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
My travels bear the most uncanny semblance to ...

Results (94 votes). Check out past polls.

Notices?