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Dienstag, 29. Januar 2008 link
"There is a tension between the [..] dual role as interactive command language and [..] programming language. A command language should be terse and convenient to type. It doesn't have to be comprehensible. Users don't have to maintain or understand a command they typed [..] a month ago. A command language can be ``write-only,'' because commands are thrown away after they are used. [..] Terse notation is important for interactive tasks."
From the generally very interesting "A Scheme Shell" (1994) by [create Olin Shivers] which not only describes his Scsh, but also explains and justifies the thoughts underlying scsh. And yes, the quote above is carefully edited to leave out any "shell" reference -- which leaves us with a general distinction between "command" and "programming" language. These considerations are also interesting regarding many other systems with interactive access: think Kdb+ with K and Q, think SQL-databases, think Erlang or Lisp-runtimes, think Mathematica, etc.
And in very related news:
Arc is out! -- "Arc is designed above all for exploratory programming: the kind where you decide what to write by writing it. A good medium for exploratory programming is one that makes programs brief and malleable, so that's what we've aimed for. This is a medium for sketching software."
A few of the more interesting bits extracted from the tutorial:
Lists/hashes/... are functions (projections):
In Arc, data structures can be used wherever functions are, and they behave as functions from indices to whatever's stored there.
Since functions of one argument are so often used in Lisp programs, Arc has a special notation for them.
You can compose functions by putting a colon between the names. I.e.
There's also a more general operator called zap that changes something to the result any function returns when applied to it. I.e.
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