"Steve Ferg" <steve.ferg.bitbuc...@gmail.com> wrote in message
news:ff92db5b-9cb0-4a72-b339-2c5ac02fb...@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
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