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

[Michael Torrie]

Steve Ferg wrote:
> Is there any particular reason why this might be a *bad* language-
> design idea?

Syntactically, using braces, begin/end blocks, python white space, and
your if/elif/then/endif structures, amounts to the same thing; they are
all equivalent.  Thus from a language pov, there's no compelling reason
to do one over the other.

One good reason to avoid the if/elif/then/endif syntax and its related
friends in a language (while/wend, do/loop, for/next) is that they
require parser support for what amounts to three or four versions of
precisely the same construct: the block.  Thus from a parser or compiler
point of view, it's far better and easier to have blocks begin and end
with something that is consistent and recognizable without a lot of
look-ahead or context.

I once started to write a parser for the QuickBasic language but found
very quickly that the grammar required a fair amount of token
look-ahead.  For example, if I found the token "End", I had to look at
least one token ahead to find out if this was an "end if" or just an
"end."  Also "end" could, if I recall, have an optional number parameter
that would set the exit errorlevel code.  Certainly QuickBasic was not
context-free and was not LL(1).

I'm not sure, but Python's grammar is LL(1) I think, and probably darn
close to context-free.