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Re: "Python for Lisp Programmers"

McCarthy used parens for grouping in the original Lisp paper


probably because parens are usually used for grouping in math,
which is what Lisp was at that point.

I considered using some alternatives to parens for s-expressions
in Arc, but decided to stick with parens.  They are more
directional than square brackets, which is important when
you have nested delimiters. Screen versions of l and r parens 
overlap in about 3 pixels, whereas square brackets overlap in all 
but 2 pixels. Compare )( and ][.  Angle-brackets are the most
directional (and would have given added hipness points for
looking like html/xml ;-) but don't seem to enclose expressions
as much.

> Historical question: Ergonomically, Parentheses are annoying because
> they
> require constant use of the SHIFT key.  Square brackets would have
> been a
> better choice.  Who chose parentheses and why?
> Note: the argument that, if square brackets were better, people would
> use
> them loses to the argument that network externalities make everyone
> do the
> same thing even if it is suboptimal (worse-is-better, microsoft,
> etc).
> The holds for infix Lisp and infix scheme.
> -Alex-
> ___________________________________________________________________
> S. Alexander Jacobson                   i2x Media
> 1-917-783-0889 voice                    1-212-697-1427 fax

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