1. Suggestion for conditional loops
Hi all,
I'd like to suggest a new syntax for conditional loops:
Use "loop" or something similar (rather than "end while") to denote the
end of a conditional loop, also allow conditional loops without a while
statement. So the basic conditional loop would look like:
do
<command_1>
<command_2>
...
loop
rather than currently
while 1 do
<command_1>
<command_2>
...
end while
Then allow a while statement at the beginning *or at the end* of the
loop:
while x < 2 do
<command_1>
<command_2>
...
loop
do
<command_1>
<command_2>
...
loop while x < 2
The advantage is in the last case, where we currently have to write:
while 1 do
<command_1>
<command_2>
...
if x >= 2 then
exit
end if
end while
The problems concerning compatibility are little, we just would have to
replace "end while" with "loop" in existing programs.
But I don't know whether this would require big changes in the parser.
Also, we now always have "end <keyword>" (end if, end for, end function, ...).
Using "do/loop" instead of "while/end while" would introduce an
exception, so I don't know whether this actually ia good idea. But at
least I wanted to tell you for discussion.
Regards,
Juergen
--
Have you read a good program lately?
2. Re: Suggestion for conditional loops
Juergen Luethje wrote:
>
> Hi all,
>
> I'd like to suggest a new syntax for conditional loops:
>
> Use "loop" or something similar (rather than "end while") to denote the
> end of a conditional loop, also allow conditional loops without a while
> statement. So the basic conditional loop would look like:
> do
> <command_1>
> <command_2>
> ...
> loop
>
> rather than currently
> while 1 do
> <command_1>
> <command_2>
> ...
> end while
>
>
> Then allow a while statement at the beginning *or at the end* of the
> loop:
> while x < 2 do
> <command_1>
> <command_2>
> ...
> loop
>
>
> do
> <command_1>
> <command_2>
> ...
> loop while x < 2
>
>
> The advantage is in the last case, where we currently have to write:
> while 1 do
> <command_1>
> <command_2>
> ...
> if x >= 2 then
> exit
> end if
> end while
>
>
> The problems concerning compatibility are little, we just would have to
> replace "end while" with "loop" in existing programs.
>
> But I don't know whether this would require big changes in the parser.
> Also, we now always have "end <keyword>" (end if, end for, end function, ...).
> Using "do/loop" instead of "while/end while" would introduce an
> exception, so I don't know whether this actually ia good idea. But at
> least I wanted to tell you for discussion.
>
> Regards,
> Juergen
>
> --
> Have you read a good program lately?
>
>
Yes, Euphoria could use a loop with the test at the end so that it runs at least
once. But I don't think it will be implemented.
One way of doing it currently instead of using exit is:
-- example from wc.ex
ch = getc(FILE)
while ch != EOF do
-- some logic to count lines, words, chars
ch = getc(FILE)
end while
The problem of course is that if you make any changes to the variable
expression, you have two lines to change instead of one.
C'est la vie with Euphoria.
</eucode>
{{{
=====================================
Too many freaks, not enough circuses.
j.
3. Re: Suggestion for conditional loops
On 15 Jul 2005, at 11:59, Juergen Luethje wrote:
>
>
> Hi all,
>
> I'd like to suggest a new syntax for conditional loops:
>
> Use "loop" or something similar (rather than "end while") to denote the
> end of a conditional loop, also allow conditional loops without a while
> statement. So the basic conditional loop would look like:
> do
> <command_1>
> <command_2>
> ...
> loop
Didn't we call those "repeat-until" loops?
Been asked for, RobC said no.
Kat
> rather than currently
> while 1 do
> <command_1>
> <command_2>
> ...
> end while
>
>
> Then allow a while statement at the beginning *or at the end* of the
> loop:
> while x < 2 do
> <command_1>
> <command_2>
> ...
> loop
>
>
> do
> <command_1>
> <command_2>
> ...
> loop while x < 2
>
>
> The advantage is in the last case, where we currently have to write:
> while 1 do
> <command_1>
> <command_2>
> ...
> if x >= 2 then
> exit
> end if
> end while
>
>
> The problems concerning compatibility are little, we just would have to
> replace "end while" with "loop" in existing programs.
>
> But I don't know whether this would require big changes in the parser.
> Also, we now always have "end <keyword>" (end if, end for, end function, ...).
> Using "do/loop" instead of "while/end while" would introduce an exception, so
> I
> don't know whether this actually ia good idea. But at least I wanted to tell
> you
> for discussion.
>
> Regards,
> Juergen
>
> --
> Have you read a good program lately?
>
>
>
>
