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Haha, I had assumed someone would mention that.

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 ...).

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If it did it would be annoying to type progn all the time and someone would make a macro...

> IIRC, Scheme requires the body of the lambda to be a single expression, doesn't it?

No, it doesn't require it.

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.

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...

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