[EMAIL PROTECTED] wrote:
> Also, you seem to be asking for an explicit way to say, "this variable
> does not respect Tennent correspondence; I know I am doing this and I
> have a good reason" --
>
>
> http://gafter.blogspot.com/2006/08/tennents-correspondence-principle-and.html
I'm suspicious of Tennent correspondence, because I think simple
variations of the statement do not match anyone's expectations.
if I understand correctly, Tennent correspondence says:
t1: any expr should be equivalent to
(function() {expr}) ()
and one of the difficulties is, what if expr has control-flow
statements, such as break or return. another difficulty is, what if
expr has lexically-scoped statements, such as local variable declarations.
assume N is a unique generated symbol. Tennant correspondence could
also be stated as
t2: any expr should be equivalent to a function in the same scope
function N() {expr}
and a call to that function
N()
that isn't true in any practical language I know, and it seems unhelpful
to say that function declaration is broken in all of them. I don't
think anyone expects that you can extract arbitrary pieces of code into
a separate function without fixing up control-flow and scoping.
and part of the usefulness of functions is that they _do_ introduce a
discontinuity, which lets you express things that are more difficult to
express without it.
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