Schwartzian Transform - History

History

The first known online appearance of the Schwartzian Transform is a December 16, 1994 posting by Randal Schwartz to a thread in comp.unix.shell, crossposted to comp.lang.perl. (The current version of the Perl Timeline is incorrect and refers to a later date in 1995.) The thread began with a question about how to sort a list of lines by their "last" word:

adjn:Joshua Ng adktk:KaLap Timothy Kwong admg:Mahalingam Gobieramanan admln:Martha L. Nangalama

Schwartz responded with:

#!/usr/bin/perl require 5; # new features, new bugs! print map { $_-> } sort { $a-> cmp $b-> } map { } <>;

This code produces the result:

admg:Mahalingam Gobieramanan adktk:KaLap Timothy Kwong admln:Martha L. Nangalama adjn:Joshua Ng

Schwartz noted in the post that he was "Speak with a lisp in Perl," a reference to the idiom's Lisp origins.

The term "Schwartzian Transform" itself was coined by Tom Christiansen in a followup reply. Later posts by Christiansen made it clear that he had not intended to name the construct, but merely to refer to it from the original post: his attempt to finally name it "The Black Transform" did not take hold ("Black" here being a pun on "schwarz", which means black in German).