Brendan Eich wrote:
Allen Wirfs-Brock put his proposal, which will not shock you who know
Smalltalk or Allen, on the whiteboard:
// Instead of lambda (a, b, c) { ... }, why not:
{ |a, b, c| ... } ?
Can't resist a historical note (which I haven't seen mentioned, but
perhaps I missed something): the Clipper language[1] in its version 5.0,
circa 1990, used this exact syntax for its "code block" data type, which
were in fact lexically scoped lambdas.[2]
Not surprisingly, Clipper adapted its code block syntax from Smalltalk.
Curly brackets were used instead of Smalltalk's square brackets,
presumably to fit better with existing Clipper syntax, which used curly
brackets for array definitions like {1,2,3} and square brackets for
array subscripts like x[2].
Googling for "clipper code block" turns up various pages with example
uses. Unfortunately, the examples that come up are all quite simple
ones, but code blocks, being lambdas, were capable of much more.
Anton
[1] Clipper was originally a compiler for Ashton-Tate's dBASE database
system/language, and was developed by the now-defunct Nantucket
Corporation. It was ultimately sold to Computer Associates.
[2] The terminology surrounding lambdas was unfamiliar to most Clipper
programmers at the time - the Clipper community referred to captured
lexical variables as "detached locals". Googling for that exact term
will turn up various examples of its use in the context of Clipper and
its descendants such as Harbour and xHarbour.
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