Re: Is multi-level function return possible?

On 16/03/2014 19:45, "Andy Walker" <news@cuboid.co.uk> wrote:


> On 16/03/14 17:19, Anton Ertl wrote:
>> Language design note: Given that nested functions have fallen out of
>> favour in the Algol-family world (in C and its offspring), I wonder if
>> they only really gain usefulness when combined with first-class
>> closures.


It would be wrong to imply that "the Algol-family world" consists of "C and
its offspring". Algol has many descendants that have have remained more
loyal to their family traditions, Ada 2012 first among them.


> They are also useful for variable hiding and space reclamation.
> If all functions are at the outermost level, then they can only access
> local or global variables, and so can communicate with each other only
> via globals or parameters. Global space can never be reclaimed except
> through sophisticated optimisations, and parameters have a run-time cost.


Exactly. Nested functions also permit information hiding and the tidying of
code by the introduction of abstractions that have only local relevance.


--
Bill Findlay
with blueyonder.co.uk;
use surname & forename;
[C fakes it with module static, but I take your point. -John]

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