[Q]Ruby LISP-ish stuff

[Josef 'Jupp' Schugt]

Saluton!

* Moses Hall; 2003-07-11, 23:45 UTC:

> def rest
> self[1,-1] end

This usually is called 'tail' while self[0] is called 'head'.

Gis,

Josef 'Jupp' Schugt
--
N'attribuez jamais à la malice ce que l'incompétence explique !
-- Napoléon

[Moses Hall]

Ah, these are the "car/cdr" or "first/rest" synonyms from Haskell?

>> def rest
>> self[1,-1] end

>
> This usually is called 'tail' while self[0] is called 'head'.

/\/\oses

[Josef 'Jupp' Schugt]

Saluton!

* Moses Hall; 2003-07-14, 12:23 UTC:

> Ah, these are the "car/cdr" or "first/rest" synonyms from Haskell?
>

> >> def rest
> >> self[1,-1] end

> >
> > This usually is called 'tail' while self[0] is called 'head'.

'head' and 'tail' seems to be quite generic terms - they occur in a
large number of texts that describe dealing with lists.

The only notable issue is that 'tail' seems to have different
meanings depending on the lanugage in common. As far as languages
that do not have native list support are concerned it means 'the last
element' while in those languages that have a list data type it means
'anything but the last element'.

The former version e.g. can be found in 'Introduction to Algorithms'
by Cormen, Leiserson and Rivest or 'Algorithms in <insert language>'
by Sedgwick.

Anyway. In my opinion 'list[1,-1]' is much more telling than 'rest'
because 'rest' means 'remainder after doing something' whereas
'list[1,-1]' specifies that 'doing something'.

Gis,

Josef 'Jupp' Schugt
--
N'attribuez jamais à la malice ce que l'incompétence explique !
-- Napoléon

[Josef 'Jupp' Schugt]

Saluton!

* Ben Giddings; 2003-07-14, 21:07 UTC:

> > meanings depending on the lanugage in common. As far as languages
> > that do not have native list support are concerned it means 'the last
> > element' while in those languages that have a list data type it means
> > 'anything but the last element'.

>
> Er, that's anything but the *first* element, right?

Right you are.

Gis,

Josef 'Jupp' Schugt
--
N'attribuez jamais à la malice ce que l'incompétence explique !
-- Napoléon