RE: block return semantic

["Eric Ries" <eries@...>]

I would be willing to have to write:

foo = dostring( "if a < b then a else b end" )

if that is simpler. The difference being that if-then-else is not changed,
only the interpreter silently keeps a "return buffer" with the result of the
last-executed statement and returns that if no return value is explicitly
specified.

Eric

> -----Original Message-----
> From: owner-lua-l@tecgraf.puc-rio.br
> [mailto:owner-lua-l@tecgraf.puc-rio.br]On Behalf Of Tom Wrensch
> Sent: Wednesday, June 27, 2001 8:24 AM
> To: Multiple recipients of list
> Subject: RE: block return semantic
>
>
> Hmm... the statement termination issue could be a real problem. I like not
> having required statement termination, but it can cause problems in some
> cases. I wonder if there's a general solution based on expression
> priorities or some kind of syntactic trick. A nice little research project
> for one of my students (* insert maniaical laugh *).
>
> The 'or' trick is nice, and covers about half of the cases where I find an
> if-then-else as expression to be useful.
>
> I agree that I would rather extend if-then-else than try to add new
> structures to a language like Lua. Its small footprint and relatively
> small number of structures is too important to give up to add minor
> features.
>
>   - Tom
>
> On Wed, 27 Jun 2001, Reuben Thomas wrote:
>
> > > Could you elaborate on the "all sorts of reasons" for not allowing
> > > if-then-else as an expression rather than just a statement?
> >
> > The sort of thing that's been discussed before: it might be nice, but it
> > would have compatibility implications (especially because of
> Lua's optional
> > statement terminators), efficiency implications; it would complicate the
> > language &c. This argument has already been had (with me as a
> proponent of a
> > more functional Lua!) on the list a few times.
> >
> > > is allowed. I find it quite useful for handling default values for
> > > uninitialized variables
> >
> > You can use the "a = f(x) or d" trick for this
> >
> > > Note that an alternative approach would be to implement a special
> > > expression version of if-then-else such as Java's <cond> ? <exp1> :
> > > <exp2> form.
> >
> > I'd prefer a more functional Lua rather than a special case.
> >
> > --
> > http://sc3d.org/rrt/ | Academics age by degrees
> >