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* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
@ 2020-10-10  7:02 Michael Heerdegen
  2020-10-10 10:03 ` Mattias Engdegård
  0 siblings, 1 reply; 7+ messages in thread
From: Michael Heerdegen @ 2020-10-10  7:02 UTC (permalink / raw)
  To: 43902


Hello,

here is a recipe for emacs -Q:

M-x calc RET
d L			;; calc-latex-language
 '			;; calc-algebraic-entry
1+1/2 RET

The result is 1, and the Trail shows alg' (1 + 1) / 2.  It does not make
much sense to me to use a precedence rule where addition has higher
precedence than division.  I know LaTeX a bit and don't expect such a
result, and it doesn't seem to be documented.  Is it intended or a bug?

TIA,

Michael.


In GNU Emacs 28.0.50 (build 62, x86_64-pc-linux-gnu, GTK+ Version 3.24.23, cairo version 1.16.0)
 of 2020-10-09 built on drachen
Repository revision: 6b346963d5a5bdb37cf3ecb50ce6d7dc6ec32d20
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12008000
System Description: Debian GNU/Linux bullseye/sid






^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-10  7:02 bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language Michael Heerdegen
@ 2020-10-10 10:03 ` Mattias Engdegård
  2020-10-13  9:40   ` Mattias Engdegård
  0 siblings, 1 reply; 7+ messages in thread
From: Mattias Engdegård @ 2020-10-10 10:03 UTC (permalink / raw)
  To: Michael Heerdegen; +Cc: 43902, Jay Belanger

Michael Heerdegen dixit:

> M-x calc RET
> d L			;; calc-latex-language
>  '			;; calc-algebraic-entry
> 1+1/2 RET
> 
> The result is 1, and the Trail shows alg' (1 + 1) / 2.  It does not make
> much sense to me to use a precedence rule where addition has higher
> precedence than division.  I know LaTeX a bit and don't expect such a
> result, and it doesn't seem to be documented.  Is it intended or a bug?


Indeed, $a+b/c$ is typeset by (La)TeX as (approx.) a + b/c which can only mean one thing, but Calc incorrectly parses it as (a+b)/c. This seems to be the consequence of an explicit change:

  commit fda9b316f84dbc6d68e6cb74b386ee4b92d81b31
  Author: Jay Belanger <jay.p.belanger@gmail.com>
  Date:   Fri Nov 16 04:15:23 2007 +0000

    (math-oper-table): Fix typo.  Reduce precedence of "/" for TeX.

  --- a/lisp/calc/calc-lang.el
  +++ b/lisp/calc/calc-lang.el
  -     ( "/"       /                185 186 )
  +     ( "/"       /                170 171 )

Jay, do you remember the reason for this change?






^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-10 10:03 ` Mattias Engdegård
@ 2020-10-13  9:40   ` Mattias Engdegård
  2020-10-13 16:22     ` Eli Zaretskii
  0 siblings, 1 reply; 7+ messages in thread
From: Mattias Engdegård @ 2020-10-13  9:40 UTC (permalink / raw)
  To: Michael Heerdegen; +Cc: Jay Belanger, 43902-done

Very well, since Jay couldn't recall the reason for the precedence change either -- it was a long time ago -- I have no reverted it back to the previous level where it sits between '+' and '*', which should be compatible with how humans interpret what TeX renders.

Pushed to master and closed.






^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-13  9:40   ` Mattias Engdegård
@ 2020-10-13 16:22     ` Eli Zaretskii
  2020-10-13 18:03       ` Mattias Engdegård
  0 siblings, 1 reply; 7+ messages in thread
From: Eli Zaretskii @ 2020-10-13 16:22 UTC (permalink / raw)
  To: Mattias Engdegård; +Cc: michael_heerdegen, 43902

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Tue, 13 Oct 2020 11:40:43 +0200
> Cc: Jay Belanger <jay.p.belanger@gmail.com>, 43902-done@debbugs.gnu.org
> 
> Very well, since Jay couldn't recall the reason for the precedence change either -- it was a long time ago -- I have no reverted it back to the previous level where it sits between '+' and '*', which should be compatible with how humans interpret what TeX renders.
> 
> Pushed to master and closed.

Thanks, but should this change be called out in NEWS?





^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-13 16:22     ` Eli Zaretskii
@ 2020-10-13 18:03       ` Mattias Engdegård
  2020-10-13 18:22         ` Eli Zaretskii
  0 siblings, 1 reply; 7+ messages in thread
From: Mattias Engdegård @ 2020-10-13 18:03 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: michael_heerdegen, 43902

13 okt. 2020 kl. 18.22 skrev Eli Zaretskii <eliz@gnu.org>:

> Thanks, but should this change be called out in NEWS?

As you wish.






^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-13 18:03       ` Mattias Engdegård
@ 2020-10-13 18:22         ` Eli Zaretskii
  2020-10-14  7:26           ` Mattias Engdegård
  0 siblings, 1 reply; 7+ messages in thread
From: Eli Zaretskii @ 2020-10-13 18:22 UTC (permalink / raw)
  To: Mattias Engdegård; +Cc: michael_heerdegen, 43902

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Tue, 13 Oct 2020 20:03:27 +0200
> Cc: 43902@debbugs.gnu.org, michael_heerdegen@web.de
> 
> 13 okt. 2020 kl. 18.22 skrev Eli Zaretskii <eliz@gnu.org>:
> 
> > Thanks, but should this change be called out in NEWS?
> 
> As you wish.

I just asked a question.  What do you think?





^ permalink raw reply	[flat|nested] 7+ messages in thread

* bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language
  2020-10-13 18:22         ` Eli Zaretskii
@ 2020-10-14  7:26           ` Mattias Engdegård
  0 siblings, 0 replies; 7+ messages in thread
From: Mattias Engdegård @ 2020-10-14  7:26 UTC (permalink / raw)
  To: Eli Zaretskii; +Cc: michael_heerdegen, 43902

13 okt. 2020 kl. 20.22 skrev Eli Zaretskii <eliz@gnu.org>:

> I just asked a question.  What do you think?

A NEWS entry is not necessary but I don't particularly mind having one either.






^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2020-10-14  7:26 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-10-10  7:02 bug#43902: 28.0.50; Calc: Wrong eval precedence rules with LaTeX language Michael Heerdegen
2020-10-10 10:03 ` Mattias Engdegård
2020-10-13  9:40   ` Mattias Engdegård
2020-10-13 16:22     ` Eli Zaretskii
2020-10-13 18:03       ` Mattias Engdegård
2020-10-13 18:22         ` Eli Zaretskii
2020-10-14  7:26           ` Mattias Engdegård

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