else on for
- Posted by kbochert at copper.net
Aug 08, 2003
--Alt-Boundary-10696.1125213
Content-description: Mail message body
On 6 Aug 2003 at 20:36, David Cuny wrote:
>
> I've implemented REDO, BREAK and CONTINUE in my own BASIC interpreter.
> Additionally, there is a ELSE clause on all the control structures, so if
> they complete without hitting a BREAK clause, the THEN executes:
>
> for i = 1 to length( s )
> if s[i] = 999 then
> break
> end if
> else
> printf( "999 was not found" )
> end for
>
> It saves having to set up a flag marking that something was found, and is
> cheap to implement.
>
I very much like this, but shouldn't the sense be reversed?
for i = 1 to length( s )
if s[i] = 999 then
break
end if
else
printf( "999 WAS found!!" )
end for
treating the 'break' as a sort of small-scale exception?
A loop being expected to run to completion, and a break
being abnormal?
By analogy with 'if - else'; The 'else' only executes when the
'for' doesn't (completely) execute.
Is 'else' the best name??
Any opinions?
Karl Bochert
--Alt-Boundary-10696.1125213
Content-type: text/html; charset=US-ASCII
Content-transfer-encoding: 7BIT
Content-description: Mail message body
<?xml version="1.0" ?><html>
<head>
<title></title>
</head>
<body>
<div align="left"><font face="Arial"><span style="font-size:10pt">On 6 Aug 2003
at 20:36, David Cuny wrote:</span></font></div>
<div align="left"><br/>
</div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> I've implemented REDO, BREAK and CONTINUE in my own
BASIC interpreter. </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> Additionally, there is a ELSE clause on all the
control structures, so if </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> they complete without hitting a BREAK clause, the
THEN executes:</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> for i = 1 to length( s
)</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> if s[i] = 999
then</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">>
break</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> end
if</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> else</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> printf( "999
was not found" )</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> end for</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> It saves having to set up a flag marking that
something was found, and is </span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> cheap to implement.</span></font></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt">> </span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">I very much
like this, but shouldn't the sense be reversed?</span></font></div>
<div align="left"><br/></div>
<div align="left"><font face="Arial" color="#7f0000"><span
style="font-size:10pt"> </span></font><font face="Arial"><span
style="font-size:10pt"> for i = 1
to length( s )</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt"> if s[i] = 999
then</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt">
break</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt"> end
if</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt"> else</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt"> printf( "999 WAS
found!!" )</span></font></div>
<div align="left"><font face="Arial"><span
style="font-size:10pt"> end for</span></font></div>
<div align="left"><br/></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">treating the
'break' as a sort of small-scale exception?</span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">A loop being
expected to run to completion, and a break</span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">being
abnormal?</span></font></div>
<div align="left"><br/>
</div>
<div align="left"><font face="Arial"><span style="font-size:10pt">By analogy
with 'if - else'; The 'else' only executes when the</span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">'for' doesn't
(completely) execute.</span></font></div>
<div align="left"><br/>
</div>
<div align="left"><font face="Arial"><span style="font-size:10pt">Is 'else' the
best name??</span></font></div>
<div align="left"><br/>
</div>
<div align="left"><font face="Arial"><span style="font-size:10pt">Any
opinions?</span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">
</span></font></div>
<div align="left"><font face="Arial"><span style="font-size:10pt">Karl
Bochert</span></font></div>
--Alt-Boundary-10696.1125213--
|
Not Categorized, Please Help
|
|
