extensions using $precommand do not work as expected

[gustafe]

Based on a question in issue #134, I'm not seeing the behavior that according to https://github.com/classilla should be there. I'm filing a bug in the hope of either a fix or a clarification...

Issue

Attempting to "alias" an existing command using the $precommand scalar in an extension does not work as documented (http://www.floodgap.com/software/ttytter/adv.html)

Repro

Create an extension called "mywebcmd", intended to add the /link command to get a link to a tweet.

$precommand = sub {
my $k = shift;
$k =~ s#^/link\s+#/web#;
return $k;
};

I loaded this extension only, no other extensions or options, and tried it out on a tweet:

b0> <@niklasorrenius> Och här en länk till @DanielOhman s fina avslöjande från i våras om hur Turkiets spionage, hot och angiveri i Sverige kan gå till http://sverigesradio.se/sida/artikel.aspx?programid=83&artikel=6661130
oysttyer> /web b0 <007
(echo 'https://twitter.com/niklasorrenius/statuses/934011568584581120')
https://twitter.com/niklasorrenius/statuses/934011568584581120
oysttyer> /link b0 <008
*** invalid command
*** to pass as a tweet, type /%%
oysttyer> <000

Expected behavior

The /link command as defined in the extension should give the same output as the /web command.

Version

oysttyer> /vcheck <007
-- checking Term::ReadLine::TTYtter version: http://www.floodgap.com/software/ttytter/01readlin.txt
-- checking oysttyer version: https://raw.githubusercontent.com/oysttyer/oysttyer/master/version_check.txt
-- your version of Term::ReadLine::TTYtter is up to date (1.4)
-- your version of oysttyer is up to date (2.9.1)