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Groups > comp.compilers > #2079
| From | bartc <bc@freeuk.com> |
|---|---|
| Newsgroups | comp.compilers |
| Subject | Re: language design after Algol 60 |
| Date | 2018-04-14 20:43 +0100 |
| Organization | virginmedia.com |
| Message-ID | <18-04-068@comp.compilers> (permalink) |
| References | (11 earlier) <18-04-034@comp.compilers> <18-04-041@comp.compilers> <18-04-046@comp.compilers> <18-04-050@comp.compilers> <18-04-065@comp.compilers> |
On 14/04/2018 05:19, Robin Vowels wrote:
> From: "bartc" <bc@freeuk.com>
> Sent: Friday, April 13, 2018 4:40 AM
>
>
>> But it is not adding extra syntax; if anything it is getting rid of it!
>> If a for-loop starts like this:
>>
>> for i:=1 to n do ...
>>
>> Then by leaving out the bits not needed you end up with this:
>>
>> to n do ...
>
> The control variable, i, must not be omitted.
> It may be required for computations within the loop
> (including subscript references).
>
> Even if not explicitly referenced within the loop,
> its value will be required for fault finding (with error control
> and/or with debugger).
Huh? Who says that?
This example is from my language (inspired by Algol68), where the
control variable /can/ be omitted. And it's not needed any more than you
need one here for this line of code repeated three times:
print "*"
print "*"
print "*"
(For that matter, it can be omitted from a C for-loop too, if only
because that language is so crude it doesn't even have the concept of a
control variable for a loop.)
>> A repeat-n-times loop (one that doesn't have to maintain an explicit
>> loop counter accessible as a reference-counted variable from the source
>> code).
>
> It's still required, as described above.
If implemented as an actual loop (rather than unrolling or whatever),
then there might be a count kept somewhere. But it doesn't need to be in
a format compatible with the regular variables in the language or be
part of its type system.
The count might also increment upwards or downwards; more likely the latter.
If a loop index is needed for fault-finding, then you just switch over
to for-loop that does have the index.
--
bartc
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Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-12 16:17 +0000
Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-13 03:02 +0000
Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-19 11:04 +0000
Re: Add nested-function support in a language the based on a stack-machine Gene Wirchenko <genew@telus.net> - 2018-03-19 12:50 -0700
Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-20 16:16 +0000
Re: Add nested-function support in a language the based on a stack-machine Martin Ward <martin@gkc.org.uk> - 2018-03-23 10:44 +0000
Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-23 18:47 +0000
Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-24 14:06 +0000
Re: algorithm performance, was Add nested-function support in a language the based on a stack-machine rpw3@rpw3.org (Rob Warnock) - 2018-03-25 07:02 +0000
Re: algorithm performance "Robin Vowels" <robin51@dodo.com.au> - 2018-03-27 01:22 +1100
Re: sorting performance, Add nested-function support in a language the based on a stack-machine w.clodius@icloud.com (William Clodius) - 2018-03-24 23:25 -0600
Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-20 09:06 +0000
Re: Add nested-function support in a language the based on a stack-machine Bill Findlay <findlaybill@blueyonder.co.uk> - 2018-03-20 12:49 +0000
Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-03-27 14:46 +0100
Re: language design after Algol 60, was Add nested-function support anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-30 14:20 +0000
Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-04-06 16:09 +0100
Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-08 14:21 +0100
Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-09 16:51 -0400
Re: language design after Algol 60, was Add nested-function support anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-04-10 05:48 +0000
Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-10 14:32 -0400
Re: language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-12 01:09 +0200
Re: language design after Algol 60, was Add nested-function support bartc <bc@freeuk.com> - 2018-04-12 11:51 +0100
Re: language design after Algol 60, was Add nested-function support bartc <bc@freeuk.com> - 2018-04-12 19:40 +0100
Re: language design after Algol 60, was Add nested-function support Martin Ward <martin@gkc.org.uk> - 2018-04-13 14:10 +0100
Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-14 14:11 +1000
RE: language design after Algol 60 "Costello, Roger L." <costello@mitre.org> - 2018-04-16 12:56 +0000
Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-17 19:08 +1000
Re: Language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-18 14:58 +1000
Re: language design after Algol 60 Gene Wirchenko <genew@telus.net> - 2018-04-18 16:12 -0700
Re: language design after Algol 60 Martin Ward <martin@gkc.org.uk> - 2018-05-01 10:42 +0100
Re: language design after Algol 60 "Robin Vowels" <robin51@dodo.com.au> - 2018-04-14 14:19 +1000
Re: language design after Algol 60 bartc <bc@freeuk.com> - 2018-04-14 20:43 +0100
Re: language design after Algol 60 Andy Walker <anw@cuboid.co.uk> - 2018-04-15 00:04 +0100
Re: language design after Algol 60, was Add nested-function support rpw3@rpw3.org (Rob Warnock) - 2018-04-12 14:05 +0000
Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-12 20:51 -0400
Re: OOP language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-13 03:22 +0000
Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-13 10:22 +0200
Re: OOP language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-14 13:40 -0400
Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-15 00:12 +0200
Re: OOP language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-15 00:23 +0200
Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-10 13:15 +0100
Re: language design after Algol 60, was Add nested-function support Hans-Peter Diettrich <DrDiettrich1@netscape.net> - 2018-04-11 13:27 +0200
Re: language design after Algol 60, was Add nested-function support "Derek M. Jones" <derek@_NOSPAM_knosof.co.uk> - 2018-04-11 20:06 +0100
Re: language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-10 18:32 +0000
Re: language design after Algol 60, was Add nested-function support George Neuner <gneuner2@comcast.net> - 2018-04-12 20:57 -0400
Re: OOP language design after Algol 60, was Add nested-function support Kaz Kylheku <157-073-9834@kylheku.com> - 2018-04-13 03:28 +0000
Re: language design after Algol 60, was Add nested-function support albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2018-05-05 13:50 +0200
Re: Add nested-function support in a language the based on a stack-machine mac <acolvin@efunct.com> - 2018-03-20 15:27 +0000
Re: Add nested-function support in a language the based on a stack-machine w.clodius@icloud.com (William Clodius) - 2018-03-12 21:09 -0600
Re: Add nested-function support in a language the based on a stack-machine Kartik Agaram <ak@akkartik.com> - 2018-03-13 13:27 -0700
Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-14 00:07 +0000
Re: Add nested-function support in a language the based on a stack-machine Kartik Agaram <ak@akkartik.com> - 2018-03-13 22:31 -0700
Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-14 14:49 +0000
Re: Add nested-function support in a language the based on a stack-machine Kaz Kylheku <157-073-9834@kylheku.com> - 2018-03-13 20:51 +0000
Re: Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-14 00:27 +0000
Re: Add nested-function support in a language the based on a stack-machine Andy Walker <anw@cuboid.co.uk> - 2018-03-14 16:37 +0000
Re: Add nested-function support in a language the based on a stack-machine anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2018-03-14 15:16 +0000
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