Language mavens: Is there a programming with "if then else ENDIF" syntax?

[bartc]

"Steve Ferg" <steve.ferg.bitbucket at gmail.com> wrote in message 
news:ff92db5b-9cb0-4a72-b339-2c5ac02fbad0 at p36g2000vbn.googlegroups.com...
> This is a question for the language mavens that I know hang out here.
> It is not Python related, except that recent comparisons of Python to
> Google's new Go language brought it to mind.
>
> NOTE that this is *not* a suggestion to change Python.  I like Python
> just the way it is.  I'm just curious about language design.
>
> For a long time I've wondered why languages still use blocks
> (delimited by do/end, begin/end, { } , etc.) in ifThenElse statements.
>
> I've often thought that a language with this kind of block-free syntax
> would be nice and intuitive:
>
>    if <condition> then
>        do stuff
>    elif <condition> then
>        do stuff
>    else
>        do stuff
>    endif
>
> Note that you do not need block delimiters.
>
> Obviously, you could make a more Pythonesque syntax by using a colon
> rather then "then" for the condition terminator.  You could make it
> more PL/I-like by using "do", etc.
>
> You can write shell scripts using if ... fi, but other than that I
> don't recall a language with this kind of syntax.
>
> Does anybody know a language with this kind of syntax for
> ifThenElseEndif?

I think Algol 68 was responsible for a lot of this syntax, but there must be 
huge numbers of languages using that those forms now, apart from C-family 
languages which evolved their own syntax (and even in C, the preprocessor 
uses #if, #elif, #endif).

Some syntaxes insist on ugly begin...end blocks, but the bracketing 
introduced by Algol68 (maybe even earlier) showed that these are redundant:

if s then s [elsif s]* [else s] fi

where s is any sequence of statements. The statements after the 'then' are 
delimited by an elsif, else or fi (endif) keyword.

The endif (or fi) is necessary to show where the final statement sequence 
ends, and fixes the dangling-else problem. (And Algol68 also allowed this 
short form:

  (a | b | c)

which is just if a then b else c fi, although it gets a bit hairy with elsif 
in there too..)

> I've often thought that a language with this kind of block-free syntax
> would be nice and intuitive: ...

You're not the first to think that.. I use these forms in my own language 
designs for that reason. And when people write pseudo-code, it always seems 
to look like this, then they go and implement it in some god-forsaken syntax 
like C++...

...For some reason I can't quite understand, this sort of clear syntax seems 
to be looked down on by 'real' programmers, who perhaps think code like this 
can't be taken seriously.


-- 
Bartc