Re: [stack] Parameters: ordered versus named

Don Groves <[email protected]> wrote:
> I believe it was sci-fi writer Robert Heinlein who coined the phrase,
> "There ain't no such thing as a free lunch."

Possibly -- that's where I read it too.

> The price we pay for the
> simplicity of
> concatenative syntax is the amount of parameter checking we must do at
> run-time which other languages to at compile-time.

Not true. Concatenative semantics don't require parameter passing, so
there is nothing to do to parameters at runtime. There are, of course,
other prices we must pay; but that's not one of them.

> The parametric details in DEFINE foo (int x, char y,void *z), etc.
> are explicit
> whereas they are implicit in DEFINE foo = ...dup...swap, etc. To give

There are concatenative languages that require explicit type
specifications; Cat, Factor, and strongForth are three very different
examples. In general, most strongly statically typed concatenative
languages have defined a syntax something like this

"DEFINE foo ( int char pointer-to-void -- int )". The syntax is
similar to Forth's classical stack diagrams.

> a truly
> realistic picture of a concatenative foo, shouldn't we also give its
> stack effect, as in this for map:
> [a b ...] [f] map ==> [af bf ...] (where xf denotes the application
> of f to x)

We definitely should -- it's a good habit, even if the language you're
using doesn't use static types, you should put that in a comment.

> One beauty of concatenative notation is the hiding of information
> such as described here,

Nothing's hidden.

> but we all know that hidden info must be dealt with
> eventually,
> unless the language is so primitive as to not care about these matters.

But this is true. (Well, mostly -- Cat does type inferencing so you
don't always have to describe the types, while Enchilada defines its
semantics so that all its types are compatible.)

> Don Groves

-Billy