Strange behavior in math mode: < and minus sign give leftarrow

Strange behavior in math mode: < and minus sign give leftarrow

[Otared Kavian]

Hi Hans,

While testing old documents with lmtx, I noticed that with recent versions of mkiv, as well as LuaMetaTeX, there is a strange behavior in math mode: when the characters < and - follow each other one gets \leftarrow… This is embarrassing when one writes inequalities for negative numbers.
So one has to separate them in order to obtain with curly braces. Can this be fixed or is it intended ?

\starttext
$\alpha < -1$ 

$\alpha \leftarrow 1$

$\alpha < {-1}$

$\alpha {<} - 1$
\stoptext

Best regards: OK
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Re: Strange behavior in math mode: < and minus sign give leftarrow

[Mikael P. Sundqvist]

On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>
> Hi Hans,
>
> While testing old documents with lmtx, I noticed that with recent versions of mkiv, as well as LuaMetaTeX, there is a strange behavior in math mode: when the characters < and - follow each other one gets \leftarrow… This is embarrassing when one writes inequalities for negative numbers.
> So one has to separate them in order to obtain with curly braces. Can this be fixed or is it intended ?
>
> \starttext
> $\alpha < -1$
>
> $\alpha \leftarrow 1$
>
> $\alpha < {-1}$
>
> $\alpha {<} - 1$
> \stoptext
>
> Best regards: OK
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
>
> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
> archive  : https://bitbucket.org/phg/context-mirror/commits/
> wiki     : http://contextgarden.net
> ___________________________________________________________________________________

Hi!

I asked about this before, and it is a feature.

It can be switched off with

\setupmathematics[
collapsing=1,
]

Hope it helps!

/Mikael
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Re: Strange behavior in math mode: < and minus sign give leftarrow

[Hans Hagen]

On 4/10/2019 9:40 AM, Mikael P. Sundqvist wrote:
> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>>
>> Hi Hans,
>>
>> While testing old documents with lmtx, I noticed that with recent versions of mkiv, as well as LuaMetaTeX, there is a strange behavior in math mode: when the characters < and - follow each other one gets \leftarrow… This is embarrassing when one writes inequalities for negative numbers.
>> So one has to separate them in order to obtain with curly braces. Can this be fixed or is it intended ?
>>
>> \starttext
>> $\alpha < -1$
>>
>> $\alpha \leftarrow 1$
>>
>> $\alpha < {-1}$
>>
>> $\alpha {<} - 1$
>> \stoptext
>>
>> Best regards: OK
>> ___________________________________________________________________________________
>> If your question is of interest to others as well, please add an entry to the Wiki!
>>
>> maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
>> webpage  : http://www.pragma-ade.nl / http://context.aanhet.net
>> archive  : https://bitbucket.org/phg/context-mirror/commits/
>> wiki     : http://contextgarden.net
>> ___________________________________________________________________________________
> 
> Hi!
> 
> I asked about this before, and it is a feature.
> 
> It can be switched off with
> 
> \setupmathematics[
> collapsing=1,
> ]
> 
> Hope it helps!
Indeed. Aditya is in charge of decisions about these defaults so if you 
want it differently you need to convince him. (I'm not sure how many 
users depend on it.)

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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___________________________________________________________________________________

Re: Strange behavior in math mode: < and minus sign give leftarrow

[Otared Kavian]

Hi Mikael,

Thanks for your quick reply.
Indeed I did not know about this feature, and setting collapsing=1 solves my problem…

Best regards: OK

> On 10 Apr 2019, at 09:40, Mikael P. Sundqvist <mickep@gmail.com> wrote:
> 
> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>> […]
> 
> Hi!
> 
> I asked about this before, and it is a feature.
> 
> It can be switched off with
> 
> \setupmathematics[
> collapsing=1,
> ]
> 
> Hope it helps!
> 
> /Mikael


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___________________________________________________________________________________

Re: Strange behavior in math mode: < and minus sign give leftarrow

[Otared Kavian]

Thanks Hans for your attention!

The problem of such an usual default is also with newcomers who would not know about this feature in ConTeXt: when one writes maths one would not guess that typing an inequality like $n < -1$ would end up in $n \leftarrow 1$. And writing such inequalities is very common… while \leftarrow is used seldom in a mathematical text.
So I think having the default collapsing=1 would be more logical, and more in line with the spirit of TeX.

I hope Aditya will be convinced…

Best regards: OK

> On 10 Apr 2019, at 09:53, Hans Hagen <j.hagen@xs4all.nl> wrote:
> 
> On 4/10/2019 9:40 AM, Mikael P. Sundqvist wrote:
>> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>>> […
> Indeed. Aditya is in charge of decisions about these defaults so if you want it differently you need to convince him. (I'm not sure how many users depend on it.)
> 
> Hans
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___________________________________________________________________________________

Re: Strange behavior in math mode: < and minus sign give leftarrow

[Aditya Mahajan]

[-- Attachment #1: Type: text/plain, Size: 1346 bytes --]

On Wed, 10 Apr 2019, Hans Hagen wrote:

> On 4/10/2019 9:40 AM, Mikael P. Sundqvist wrote:
>> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>>> 
>>> Hi Hans,
>>> 
>>> While testing old documents with lmtx, I noticed that with recent versions 
>>> of mkiv, as well as LuaMetaTeX, there is a strange behavior in math mode: 
>>> when the characters < and - follow each other one gets \leftarrow… This is 
>>> embarrassing when one writes inequalities for negative numbers.
>>> So one has to separate them in order to obtain with curly braces. Can this 
>>> be fixed or is it intended ?
>>> 
>>> \starttext
>>> $\alpha < -1$
>>> 
>>> $\alpha \leftarrow 1$
>>> 
>>> $\alpha < {-1}$
>>> 
>>> $\alpha {<} - 1$
>>> \stoptext
>>> 
>>> Best regards: OK
>> 
>> Hi!
>> 
>> I asked about this before, and it is a feature.
>> 
>> It can be switched off with
>> 
>> \setupmathematics[
>> collapsing=1,
>> ]
>> 
>> Hope it helps!
> Indeed. Aditya is in charge of decisions about these defaults so if you want 
> it differently you need to convince him. (I'm not sure how many users depend 
> on it.)

We can turn it off by default. But it might be better to have a more 
versbose interface:

   \setupmathematics[collapsing=yes|no]

with the default value being collapsing=no.

Aditya

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Re: Strange behavior in math mode: < and minus sign give leftarrow

[Alan Braslau]

On Wed, 10 Apr 2019 10:09:31 +0200
Otared Kavian <otared@gmail.com> wrote:

> The problem of such an usual default is also with newcomers who would not know about this feature in ConTeXt: when one writes maths one would not guess that typing an inequality like $n < -1$ would end up in $n \leftarrow 1$. And writing such inequalities is very common… while \leftarrow is used seldom in a mathematical text.
> So I think having the default collapsing=1 would be more logical, and more in line with the spirit of TeX.
> 
> I hope Aditya will be convinced…

And since we have utf-8 input, such "features" are anachronistic and should not be on by default. ←

Alan
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Re: Strange behavior in math mode: < and minus sign give leftarrow

[Hans Hagen]

On 4/10/2019 2:19 PM, Aditya Mahajan wrote:
> On Wed, 10 Apr 2019, Hans Hagen wrote:
> 
>> On 4/10/2019 9:40 AM, Mikael P. Sundqvist wrote:
>>> On Wed, Apr 10, 2019 at 9:21 AM Otared Kavian <otared@gmail.com> wrote:
>>>>
>>>> Hi Hans,
>>>>
>>>> While testing old documents with lmtx, I noticed that with recent 
>>>> versions of mkiv, as well as LuaMetaTeX, there is a strange behavior 
>>>> in math mode: when the characters < and - follow each other one gets 
>>>> \leftarrow… This is embarrassing when one writes inequalities for 
>>>> negative numbers.
>>>> So one has to separate them in order to obtain with curly braces. 
>>>> Can this be fixed or is it intended ?
>>>>
>>>> \starttext
>>>> $\alpha < -1$
>>>>
>>>> $\alpha \leftarrow 1$
>>>>
>>>> $\alpha < {-1}$
>>>>
>>>> $\alpha {<} - 1$
>>>> \stoptext
>>>>
>>>> Best regards: OK
>>>
>>> Hi!
>>>
>>> I asked about this before, and it is a feature.
>>>
>>> It can be switched off with
>>>
>>> \setupmathematics[
>>> collapsing=1,
>>> ]
>>>
>>> Hope it helps!
>> Indeed. Aditya is in charge of decisions about these defaults so if 
>> you want it differently you need to convince him. (I'm not sure how 
>> many users depend on it.)
> 
> We can turn it off by default. But it might be better to have a more 
> versbose interface:
> 
>    \setupmathematics[collapsing=yes|no]
> 
> with the default value being collapsing=no.

we already have "none" and th enumbers represent:

1 specials
2 specials + mathlist
3 mathlist + specials

Now that Alan is entering his math in unicode symbols we can default to 
'none'.

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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maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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___________________________________________________________________________________