Print Page - (lookup nil x) -> 1st item?

Title: (lookup nil x) -> 1st item?
Post by: kanen on January 28, 2011, 06:02:02 PM

Try this:

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> (set 'tr '( (1 "foo") (2 "bar") (3 "baz")))
((1 "foo") (2 "bar") (3 "baz"))
> (lookup nil tr)
"foo"

Unless I'm missing something, shouldn't (lookup) return nil?

By the way, I got here because I'm actually doing:

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(lookup x tr)

And x can be nil.

Title: Re: (lookup nil x) -> 1st item?
Post by: Lutz on January 29, 2011, 05:04:46 AM

This is fixed in the upcoming stable version 10.3.0. There is a preview here:

http://www.newlisp.org/downloads/development/inprogress/

Note, that I could only reproduce the first case in your post, not the second case where a key variable x is set to nil, where it worked correctly for me.

In upcoming 10.3.0 nil is a legitimate lookup item:

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newLISP v.10.3.0 on OSX IPv4/6 UTF-8, execute 'newlisp -h' for more info.

> (set 'tr '( (1 "foo") (nil "bar") (3 "baz")))
((1 "foo") (nil "bar") (3 "baz"))
> (lookup nil tr)
"bar"
>

the second sublist contains nil in the lookup position.

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Forum => newLISP in the real world => Topic started by: kanen on January 28, 2011, 06:02:02 PM