* [NTG-context] letfrozen?
@ 2023-06-12 8:57 Hans van der Meer via ntg-context
2023-06-12 9:12 ` Hans Hagen via ntg-context
0 siblings, 1 reply; 6+ messages in thread
From: Hans van der Meer via ntg-context @ 2023-06-12 8:57 UTC (permalink / raw)
To: NTG ConTeXt; +Cc: Hans van der Meer
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The manual LMTX-primitives on page 21 tells me:
You can explicitly freeze an unfrozen macro.
...
A redefinition will now give: You can't redefine a frozen macro.
But is this true? The following code seems to contradict this:
\def\HOME{myhome}
\writestatus{1}{\meaning\HOME}
\letfrozen\HOME
\writestatus{2}{\meaning\HOME}
\def\HOME{other home}
\writestatus{3}{\meaning\HOME}

Is this mechanism broken? It looks so useful to prevent accidental redefinition!
dr. Hans van der Meer
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* Re: [NTG-context] letfrozen?
2023-06-12 8:57 [NTG-context] letfrozen? Hans van der Meer via ntg-context
@ 2023-06-12 9:12 ` Hans Hagen via ntg-context
2023-06-12 10:32 ` Hans van der Meer via ntg-context
0 siblings, 1 reply; 6+ messages in thread
From: Hans Hagen via ntg-context @ 2023-06-12 9:12 UTC (permalink / raw)
To: Hans van der Meer via ntg-context; +Cc: Hans Hagen
On 6/12/2023 10:57 AM, Hans van der Meer via ntg-context wrote:
> The manual LMTX-primitives on page 21 tells me:
> You can explicitly freeze an unfrozen macro.
> ...
> A redefinition will now give: You can't redefine a frozen macro.
>
> But is this true? The following code seems to contradict this:
>
> \def\HOME{myhome}
> \writestatus{1}{\meaning\HOME}
> \letfrozen\HOME
> \writestatus{2}{\meaning\HOME}
> \def\HOME{other home}
> \writestatus{3}{\meaning\HOME}
>
>
> 
>
> Is this mechanism broken? It looks so useful to prevent accidental redefinition!
here i run with
\enabledirectives[overloadmode=error]
(you can do that in cont-sys.mkxl)
\enabledirectives[overloadmode=warning]
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [NTG-context] letfrozen?
2023-06-12 9:12 ` Hans Hagen via ntg-context
@ 2023-06-12 10:32 ` Hans van der Meer via ntg-context
2023-06-12 17:47 ` Hans Hagen via ntg-context
0 siblings, 1 reply; 6+ messages in thread
From: Hans van der Meer via ntg-context @ 2023-06-12 10:32 UTC (permalink / raw)
To: NTG ConTeXt; +Cc: Hans van der Meer
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> On 12 Jun 2023, at 11:12, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
>
> On 6/12/2023 10:57 AM, Hans van der Meer via ntg-context wrote:
>> The manual LMTX-primitives on page 21 tells me:
>> You can explicitly freeze an unfrozen macro.
>> ...
>> A redefinition will now give: You can't redefine a frozen macro.
>> But is this true? The following code seems to contradict this:
>> \def\HOME{myhome}
>> \writestatus{1}{\meaning\HOME}
>> \letfrozen\HOME
>> \writestatus{2}{\meaning\HOME}
>> \def\HOME{other home}
>> \writestatus{3}{\meaning\HOME}
>> 
>> Is this mechanism broken? It looks so useful to prevent accidental redefinition!
>
> here i run with
>
> \enabledirectives[overloadmode=error]
>
> (you can do that in cont-sys.mkxl)
>
> \enabledirectives[overloadmode=warning]
> Hans
>
Pity. Now I get on loading the tex file:
"csname overload > fatal error, protection level 4, control sequence 'nbsp', properties 'immutable', file 't-hvdm-text.tex', line 63
while I had hoped that frozen would give me something like:
illegal attempt to redefine \HOME
Byproduct (not unwanted) the above illegal redefinition to be solved :-)
May I ask why obviously the frozen-mechanism seems (yet?) unimplemented?
dr. Hans van der Meer
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [NTG-context] letfrozen?
2023-06-12 10:32 ` Hans van der Meer via ntg-context
@ 2023-06-12 17:47 ` Hans Hagen via ntg-context
2023-06-13 10:43 ` Hans van der Meer via ntg-context
0 siblings, 1 reply; 6+ messages in thread
From: Hans Hagen via ntg-context @ 2023-06-12 17:47 UTC (permalink / raw)
To: ntg-context; +Cc: Hans Hagen
On 6/12/2023 12:32 PM, Hans van der Meer via ntg-context wrote:
>> On 12 Jun 2023, at 11:12, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
>>
>> On 6/12/2023 10:57 AM, Hans van der Meer via ntg-context wrote:
>>> The manual LMTX-primitives on page 21 tells me:
>>> You can explicitly freeze an unfrozen macro.
>>> ...
>>> A redefinition will now give: You can't redefine a frozen macro.
>>> But is this true? The following code seems to contradict this:
>>> \def\HOME{myhome}
>>> \writestatus{1}{\meaning\HOME}
>>> \letfrozen\HOME
>>> \writestatus{2}{\meaning\HOME}
>>> \def\HOME{other home}
>>> \writestatus{3}{\meaning\HOME}
>>> 
>>> Is this mechanism broken? It looks so useful to prevent accidental redefinition!
>>
>> here i run with
>>
>> \enabledirectives[overloadmode=error]
>>
>> (you can do that in cont-sys.mkxl)
>>
>> \enabledirectives[overloadmode=warning]
>> Hans
>>
>
> Pity. Now I get on loading the tex file:
> "csname overload > fatal error, protection level 4, control sequence 'nbsp', properties 'immutable', file 't-hvdm-text.tex', line 63
>
> while I had hoped that frozen would give me something like:
> illegal attempt to redefine \HOME
>
> Byproduct (not unwanted) the above illegal redefinition to be solved :-)
>
> May I ask why obviously the frozen-mechanism seems (yet?) unimplemented?
It's okay and has been around for quite a while now.
\enabledirectives[overloadmode=error]
\starttext
\frozen\def\HOME{!!!!}
\def\HOME{!!!!!}
\stoptext
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [NTG-context] letfrozen?
2023-06-12 17:47 ` Hans Hagen via ntg-context
@ 2023-06-13 10:43 ` Hans van der Meer via ntg-context
2023-06-13 17:23 ` Hans Hagen via ntg-context
0 siblings, 1 reply; 6+ messages in thread
From: Hans van der Meer via ntg-context @ 2023-06-13 10:43 UTC (permalink / raw)
To: NTG ConTeXt; +Cc: Hans van der Meer
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Of course. But without that \enabledirective I can redefine the frozen macro at will, as a simple test did show.
The crux, however, is that one wants to protect the frozen code always, irrespective of that directive setting.
dr. Hans van der Meer
> On 12 Jun 2023, at 19:47, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
>
> On 6/12/2023 12:32 PM, Hans van der Meer via ntg-context wrote:
>>> On 12 Jun 2023, at 11:12, Hans Hagen via ntg-context <ntg-context@ntg.nl> wrote:
>>>
>>> On 6/12/2023 10:57 AM, Hans van der Meer via ntg-context wrote:
>>>> The manual LMTX-primitives on page 21 tells me:
>>>> You can explicitly freeze an unfrozen macro.
>>>> ...
>>>> A redefinition will now give: You can't redefine a frozen macro.
>>>> But is this true? The following code seems to contradict this:
>>>> \def\HOME{myhome}
>>>> \writestatus{1}{\meaning\HOME}
>>>> \letfrozen\HOME
>>>> \writestatus{2}{\meaning\HOME}
>>>> \def\HOME{other home}
>>>> \writestatus{3}{\meaning\HOME}
>>>> 
>>>> Is this mechanism broken? It looks so useful to prevent accidental redefinition!
>>>
>>> here i run with
>>>
>>> \enabledirectives[overloadmode=error]
>>>
>>> (you can do that in cont-sys.mkxl)
>>>
>>> \enabledirectives[overloadmode=warning]
>>> Hans
>>>
>> Pity. Now I get on loading the tex file:
>> "csname overload > fatal error, protection level 4, control sequence 'nbsp', properties 'immutable', file 't-hvdm-text.tex', line 63
>> while I had hoped that frozen would give me something like:
>> illegal attempt to redefine \HOME
>> Byproduct (not unwanted) the above illegal redefinition to be solved :-)
>> May I ask why obviously the frozen-mechanism seems (yet?) unimplemented?
> It's okay and has been around for quite a while now.
>
> \enabledirectives[overloadmode=error]
>
> \starttext
>
> \frozen\def\HOME{!!!!}
>
> \def\HOME{!!!!!}
>
> \stoptext
>
>
> -----------------------------------------------------------------
> Hans Hagen | PRAGMA ADE
> Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
> tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
> -----------------------------------------------------------------
>
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
> webpage : https://www.pragma-ade.nl / http://context.aanhet.net
> archive : https://bitbucket.org/phg/context-mirror/commits/
> wiki : https://contextgarden.net
> ___________________________________________________________________________________
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___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
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___________________________________________________________________________________
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [NTG-context] letfrozen?
2023-06-13 10:43 ` Hans van der Meer via ntg-context
@ 2023-06-13 17:23 ` Hans Hagen via ntg-context
0 siblings, 0 replies; 6+ messages in thread
From: Hans Hagen via ntg-context @ 2023-06-13 17:23 UTC (permalink / raw)
To: Hans van der Meer via ntg-context; +Cc: Hans Hagen
On 6/13/2023 12:43 PM, Hans van der Meer via ntg-context wrote:
> Of course. But without that \enabledirective I can redefine the frozen macro at will, as a simple test did show.
> The crux, however, is that one wants to protect the frozen code always, irrespective of that directive setting.
there are several caregories, like primitive, permanent, instance,
mutable, immutable and frozen
at some point we could deepfreeze them all but in the end that makes no
sense because then we can't for instance run tikz
so in the end it's mostly about warnings and errors (one can actually
distinguish between categories)
there's also \overloaded and \aliased and \enforced etc
of course you can at some point do
\newcount\overloadmode
but who can predict side effects (and one can argue that tex is
progrmamable and that users get what they ask for) and keep in mind that
all should also not hit performance too badly
there's quite a bit involved here .. pretty all context commands have
some kind of flagging and protection (which also is handy for tracing)
You can spent hours playing with prefixes:
\frozen
\permanent
\immutable
\mutable
%primitive
\noaligned
\instance
\untraced
\global
\tolerant
\protected
\overloaded
\aliased
\immediate
\deferred
\semiprotected
\enforced
\inherited
\constant
if you're in the mood.
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context
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wiki : https://contextgarden.net
___________________________________________________________________________________
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2023-06-12 17:47 ` Hans Hagen via ntg-context
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