Re:Stop writing lambda expressions in Python
by another-cuppa on Friday September 28, 2018 @01:57PM
(#18095477)
If it did it would be annoying to type progn all the time and someone would make a macro...
Re:Stop writing lambda expressions in Python
by lispm on Friday September 28, 2018 @10:29AM
(#18093639)
> IIRC, Scheme requires the body of the lambda to be a single expression, doesn't it?
No, it doesn't require it.
Re:Stop writing lambda expressions in Python
by kbp on Sunday September 30, 2018 @04:32PM
(#18108239)
It used to, though. From the original Scheme paper: Note that in SCHEME, unlike MacLISP, the body of a LAMBDA expression is not an implicit PROGN.
Re:Stop writing lambda expressions in Python
by lispm on Monday October 01, 2018 @03:38AM
(#18110678)
Changed in the early/mid 80s I think. AI Memo 848 (Revised Revised Report) from 1985 has it already as an 'essential special form': (lambda (var1 ...) expr1 expr2 ...)
R1RS does not permit it. And: In the the R1RS syntax BNF there is a (DEFINE (<identifier> <identifier list>) <form>) with one form. But later in the document it is a '<form list>'... Then the LAMBDA syntax has a BODY, but it is only a FORM...
But most Lisps are pretty rough-and-ready about these sorts of things. IIRC, Scheme requires the body of the lambda to be a single expression, doesn't it? And then you just cheat your way out of it with (begin ...).