The \multicolumn command allows to set vertical lines for individual rows.
These are not yet displayed, but if they are supported one day, the code in
a27ff13663 needs to be adjusted. This change hints at the adjustment.
This is a fixup to commit 39329935. The two fixes are
* add forgotten offset `y' when drawing the line
* in order to have a continuous vertical line, draw from the offset of
the previous row.
Fixes bug #10363.
Now by default all insets paint their own background when needed. This
means that 63cf3297 and part of 9940acc5 can be reverted.
To avoid extra painting, background drawing is disabled for
InsetCommand and InsetCollapsable. These insets draw background as
part of their normal drawing activity.
This will avoid drawing artifacts with InsetNewpage, InsetVSpace and
probably some others.
For reference, the bug was that quote insets grew bolder because, when
painted over themselves, anti-aliasing made them darker.
It turned out that the fix there created others than were
painstakingly fixed: #7164, #7165, #7174, #7193... More recently, it
created other problems:
http://article.gmane.org/gmane.editors.lyx.devel/163471
We use the right fix here:
* draw background of quote inset when not doing full repaint
* draw background of math macro template when not doing full repaint
* remove hack that grew from #4889 fix.
This is the well known file locking problem: The TempFile class keeps the
created file locked for the own process, and this prevents the CAS to read it.
The main thing it does is integrate mouse-modifiers into the
FuncRequest machinery. Previously, these had to be passed
separately, which led to some ugly function signatures.
There was also an unnecessary form of the constructor, which
can now be removed.
No change of behavior is intended.
The only exceptions are:
- The purpose of the header is to drag in the used symbol, e.g. unique_ptr.h
- The used symbol is inside a class or a namespace other than lyx
The reason for this is that global 'using' statements effectively forbid to
use the used symbols in any other namespace in the whole program, since simply
adding or removing an #include of the corresponding header subtly changes the
name lookup. The namespace lyx is sort of global, so it should not have these
statements either.
Maxima uses \it as a markup for multiletter variables. However,
it has been reported that since texlive 2016 using \it in math
mode produces an error, even though I was not able to reproduce.
Anyway, this can be avoided by replacing the old-style construct
"{\it ...}" with the new-style one "\mathit{...}".
The problem has also been reported upstream:
https://sourceforge.net/p/maxima/bugs/3181/
but this workaround will hold whatever the resolution.
This was dead code that did never work, and most of it was boilerplate that
you can steel in 15 minutes from any existing math inset. Apart from that it
did contain a pointer to InsetXYMatrix which would create the same problems
we saw with the macros.
This requires to change many docstrings into std::strings. The logic behind that
is that they represent a fixed set of math fonts, and therefore “string” means
here “poor man's enum” rather than text (this is consistent with MetricsBase).
Profiling of scrolling inside a document over macro-instensive areas:
Before the patch:
44,1% BufferView::updateMetrics()
-> 34,8% InsetMathHull::metrics()
-> 9,8% FontSetChanger::FontSetChanger()
28,4% BufferView::draw()
After the patch:
35,3% BufferView::updateMetrics()
-> 27,2% InsetMathHull::metrics
-> 0,4% FontSetChanger::FontSetChanger()
47,5% BufferView::draw()
FontSetChanger::FontSetChanger() is made 41x less expensive (with reference
BV::draw()) just by removing this conversion. The remaining 0,4% could be
squished by replacing the strings with a proper enum, but this is premature. Of
course, this only treats the symptoms: there is no good reason that this
function is called 45500 times over the time of 40 repaints.
Replace the manual manipulation of a stack of RowEntries with a Changer
function. When I introduced the stack of RowEntries, I did not know about the
Changer mechanism.
RefChanger temporarily assigns a value to a non-const reference of any
kind. RefChanger provides a flexible and uniform generalisation of the various
scope guards previously derived from the old Changer class in MetricsInfo.h.
As before, a temporary assignment lasts as long as the Changer object lives. But
the new Changer is movable. In particular, contorsions are no longer needed to
change a private field. Special code can be moved into the appropriate classes,
and it is no longer necessary to create a new class for each specific use.
Syntax change:
FontSetChanger dummy(mi.base, value);
-> Changer dummy = mi.base.changeFontSet(value);
New function for generating arbitrary Changers:
Changer dummy = make_change(ref, val, condition);
Bugfix:
* Fix the display of \displaystyle{\substack{\frac{xyz}{}}} (missing style
change).
This is a mechanical replacement. For now it seems that unique_ptrs are
essentially used for exception-safety. More could certainly be done to clarify
pointer ownership in general.
The parameter passed to allowDisplayMath will need to be copied, so it
made sense to pass it by value. Since Coverity complains about that,
the code is rewritten to make the copy explicit.
This is a first cleanup step. More complex rules have to be
implemented on top of this.
Use proper spacing \thinmuskip, \medmuskip and \thickmuskip instead of
ad-hoc values.
Rename isRelOp to isMathRel and introduce isMathBin and isMathPunct
(for InsetMathChar and InsetMathSymbol). Update the categories of
characters in InsetMathChar according to LaTeX source (fontmath.ltx).
Set correctly the spacing around mathrel, mathbin and mathpunct
elements. Use \thinmuskip around MathDelim instead of a hardcoded 4.
This is related to bug #8883.
The old name would be confusing wrt setSelection(), which does additional checks.
This one is a pure acessor, and the more complete methods are
* setSelection(), which avoids empty selections
* clearSelection(), which resets anchor, and sets word selection and mark more to false.
Most of the code should use these two instead of selection(bool), but this is for later.
Some headers contain
class Foo;
whereas there is no class Foo.
The list of class statements is given by
classes=`git grep '^\(class\|struct\) [a-zA-Z_:]*;' src | sed 's/^.* \(.*\);/\1/'|sort -u`
The ones that are useless are:
for c in $classes ; do grep -r "\\<$c\\>" src| grep -vq '^[^:]*:\(class\|struct\) [a-zA-Z_:]*;' || echo "$c"; done
Those two functions used two different hackish and buggy
implementation to know when the function is disabled. Replace that by
asking the containing inset whether it accepts inserting display math
inset.
Fixes bug #10033.
The old name conflicted with the newly introduced Inset::isTable.
Now the meaning is as follows.
* Inset::isTable() is true when the inset is composed of lines and columns
* InsetMathHull::allowsTabularFeatures is true when the current type of hull allows for tabular-like functions.
inset-select-all has 3 levels
1. select current cell
2. select all cells
3. select inset from outside.
The second level makes sense for tables (text and math), but not for things like a math fraction.
Introduce a new method Inset::isTable() that allows to detect this case properly and skip level 2.
Remove in particular all comparisons < and >= involving HullType.
Add a guard to make sure that mutate() only operates on types it has been
designed for. Then I figured I could use this new knowledge to give feedback
when math-mutate is not implemented via getStatus(). (To test this, insert a
regexp in Advanced Search & Replace and try to change it into a standard
equation via the contextual menu.)
AMS align environment should have some spacing between odd and even columns.
Add a new virtual method displayColSpace() to InsetMathGrid, InsetMathHull and
InsetMathSplit.
A longstanding problem... (related: #1861)
The columns in AMS math environments have a fixed alignment (colAlign() in
InsetMathGrid.cpp). We set this alignment for display (Georg's
displayColAlign()) in InsetMathHull and InsetMathSplit. This is done according
to tests and documentation for the various environments.
There is also some mechanical code factoring via colAlign().
Finally, I disable setting the horizontal alignment in InsetMathSplit, which has
no impact on the LaTeX output, and has no longer any impact on the screen. (As
for vertical alignment I discovered that it was in fact customisable for
\aligned & friends! I hope that the more faithful interface will let other
users discover that too.)
This fixes a failing unit test with 32bit gcc 4.9.3 and -O2 optimization:
It computed 9953 instead of 9954 for Length::inPixels() of value 2342.
The reason for this is probably different rounding behaviour caused by storing
the unrounded value in a processor register (uses 80bit accuracy) vs. writing
it back to memory (uses 64bit accuracy). The unrounded value is very close to
9953.5 (which is not representable as an exact IEEE floating point value).
Apart from that, having a proper function for rounding makes the code more
readable, and has the nice side effect to make Length::inPB() work for
negative lengths as well.
This concerns InsetPreview, InsetIPA and InsetMathHull.
Caching such a value is bad when opening the same buffer in two views.
In this case, it is not necessary to remember use_preview_ at all,
actually.
Also remove private member dim_ which is not used and remove some trailing whitespace.
Fixes bugs #9085 abd #9957.
The tabular-features LFUN was merged with "inset-modify tabular" when
simplifying the tabular dialog at b5049e7. This choice later indirectly caused a
few regressions (#7308, #9794).
I reintroduce tabular-feature to allow more flexibility for user
commands, whereas "inset-modify tabular" is now reserved for the tabular
dialog. In particular, inset-modify tabular is no longer caught by math grid
insets. The name tabular-feature is kept to avoid renaming icons.
Known issues:
* After successfully applying a tabular command, the cursor is truncated to the
table.
* Note that the tabular dialog still has similar issues that are inherited from
the achitecture of the dialog menu. For instance the pref change can be
mis-dispatched to an inset inside a cell and cause an error, for instance:
Lexer.cpp (934): Missing 'Note'-tag in InsetNote::string2params. Got
tabular instead. Line: 0
Maybe the inset-modify LFUN should be modified to treat commands coming from
the wrong dialog (by checking the type) as unknown and undispatched so that
the parent can get it. In that case a non AtPoint variant of inset-modify
could be reintroduced in order to generalise tabular-feature. See:
http://mid.gmane.org/n4rdk1$efj$1@ger.gmane.org
AMS align environment should have some spacing between odd and even columns.
Add a new virtual method displayColSpace() to InsetMathGrid, InsetMathHull and
InsetMathSplit.
I have no clue why this was automatically committed, I just applied the path, nothing more.
This reverts commit bb5470b5d1.
# Conflicts:
# src/mathed/InsetMathGrid.cpp
# src/mathed/InsetMathSplit.cpp
AMS align environment should have some spacing between odd and even columns.
Add a new virtual method displayColSpace() to InsetMathGrid, InsetMathHull and
InsetMathSplit.
A longstanding problem... (related: #1861)
The columns in AMS math environments have a fixed alignment (colAlign() in
InsetMathGrid.cpp). We set this alignment for display (Georg's
displayColAlign()) in InsetMathHull and InsetMathSplit. This is done according
to tests and documentation for the various environments.
There is also some mechanical code factoring via colAlign().
Finally, I disable setting the horizontal alignment in InsetMathSplit, which has
no impact on the LaTeX output, and has no longer any impact on the screen. (As
for vertical alignment I discovered that it was in fact customisable for
\aligned & friends! I hope that the more faithful interface will let other
users discover that too.)
Gcc STL debugging feature asserts when swapping an object with itself. This happens in some cases with math grids that have only one column.
A quick review of other uses of swap() in the code base did not reveal any other dubious case.
Fixes bug #9902.
The pointer macroInset points to a vector element. When another element is inserted in this vector, some reallocation occur and the pointer points to a deleted element.
This does not crash LyX by default, but it is bad enough to make valgrind cry.
See ticket #9804.
We already have a CoordCache of insets dimensions. It is not necessary
to store the same information in two places.
Give a name to CoordCache tables types to improve code readability.
Remove ParagraphMetrics::singleWidth, which is not used anymore.
This deep copy used to mess with the unique identifier: what TexRow saw was
different from the original uid. There may also be performance improvements.
(Using Georg's suggestion)
These features are active in DEVEL_VERSION when Debug is set to LATEX.
1. The TexRow information is prepended to the source panel.
2. Clicking on any line in the source triggers reverse search. (This would be an
interesting feature to implement on the user side, but we need a proper LFUN.)
WriteStream is now built from an otexstream instead of an odocstream, and
therefore counts lines in a TexRow. Calls to TexRow are added in relevant places
in math insets.
This finishes adding line tracking for math in the source panel and for forward
search.
The id is just the memory address.
The status bar now spits out the math inset uid information when in a math cell
in DEVEL_VERSION, like it already does when in a paragraph.
This is preliminary work for extending the cursor<->row tracking to math.
These were found by cppcheck:
Member variable 'x' is not initialized in the constructor.
The crash #9788 would not have happened if this had been done earlier.
The test case did show several problems:
- The alignment argument was not parsed correctly if it was not in braces
- There one column too much created, since I did not take into account that
the current cell must bge replaced by the multicolumn cell
- If the last line of an array contained only an empty multicolumn cell, then
the complete multicolumn was swallowed
- The decision whether to output the column separator & was sometimes wrong
for multicolumns
This fixes the crash of bug #9788. However, the misparsing of \multicolumn
is still there: LyX thinks that the array has three columns, it inserts an
additional one before the multicolumn.
Use the function support:truncateWithEllipsis() to shorten a docstring with
... at the end. Actually we use U+2026 HORIZONTAL ELLIPSIS instead of "..." when
automatically shortening strings. This is to be consistent with Qt's own
truncation and is much nicer on the screen.
This includes the bugs #9575 and #9572 regarding broken text elision in the
outliner.
Known issues (non-regressions):
* TocBackend::updateItem() should be rewritten to update all TOCs. (#8386)
* "..." should be replaced with … everywhere else on the interface (including
translation strings).
* We should prefer to rely on QFontMetrics::elidedText() to truncate strings
with an ellipsis whenever possible, or an equivalent for the buffer view
dependent on the font metrics. See the warning in src/support/lstrings.h.
* New TOC "math-macro". This means that math macros can now be accessed in the
outline pane in their order of appearance or in alphabetical order, and can be
searched using the filter.
* Lists of floats now show subfloats deeper in the navigation menu
* The arbitrary 30 element cut-off after which nothing is shown except "Open
Navigator..." is removed. Menus now have no limit in size, so Qt may display
them scrollable. In exchange, we always show "Open outliner..." at the
beginning. I tested for performance issues with a rather complex document and
it is fine; but this does not exclude corner cases with lots of TOC entries of
a certain kind. If necessary, populating the navigation sub-menu should be
delayed like the main menu.
* Elements that do not contribute to the output (e.g. in a note, a disabled
branch) are now preceded with a symbol indicating this status. (The machinery
was already there; I wonder why it was not implemented already.) I have chosen
U+274E NEGATIVE SQUARED CROSS MARK.
* Fix the contextual menus in the outliner (bug introduced at 94e992c5).
* Toc item now move to the caption when present, but first center on the float,
to prevent the situation where the caption is at the top of the screen and the
contents of the float is off-screen above the caption.
(Internally, the action of the toc items can now be customised)
* Fix the LyXHTML output. Disabled captions no longer appear in the list of
figures.
Remove unwanted clearSelection()s in MathData::updateMacros(). These calls broke
text selection with keyboard and mouse, search-and-replace, restoring selection
after Undo, etc. in a document with math macros since 1.6.0. (Regression at
6aa54673 and 12314897)
I do not know the purpose of these calls, but the selection code has been worked
on since, and I cannot produce undesired behaviour after removing
them.
We introduce TocBuilder for building TOCs that take into account both float
insets and their captions.
* Floats without caption are shown with their content.
* Floats with a caption are shown with their caption, but clicking the entry now
correctly moves to the float and not to the caption.
* Subsequent captions produce additional entries in the TOC.
* Figures and subfigures are correctly ordered in the outliner.
* New TOC "senseless" for captions appearing alone (a bit like broken references
are still displayed in the menu and outliner).
* Disable LFUN_CAPTION_INSERT if there is already a caption in a listing
Known issues:
* Inconsistent output for includes located inside floats
* We should record the end of the float in addition of the beginning for a more
accurate cursor -> outliner entry conversion
(#9762)
* fixes a bug where this was already the expected behaviour of
math-subscript and math-superscript but failed.
* corrects the behaviour where if there is \newcommand in the
selection, then a corresponding macro template is introduced
instead of a math inset.
* fixes a bug where math-display, math-subscript and math-supscript
would also introduce such a macro template in a way unrelated to
their function. Now it only happens with math-mode without
arguments.
* fixes a bug where a text that does not denote a macro definition,
e.g. "aaa\newcommandaaa", would produce \invalidmacro.
These were all found by cppcheck. Even in constructors that are there "only
because of std containers" the class should be initialized correctly. You can
never know whether such an object does not get used, and then a nice crash
caused by dereferencing a NULL-pointer is better than undefined behaviour.
The functions reverseDirectionNeeded() and reverseDirectionNeeded() do
not rely on the Bidi class. The first one is changed into a Cursor
method, and the second one is replaced with explicit code.
The bug workaround added an extra repaint, which can be very bad when
editing large tables.
It turns out that the bug this is trying to fix is due to the handling
of LFUN_LINE_END in InsetMathGrid. Adding the same code as in
InsetMathNest fixes the problem.
The workaround can therefore be removed.
When the cursor had idx > 0 (since math-display does merging anyways),
reset cursor to the start of the inset. This looks less strange than
setting it at the end.
Now at least the basic case of a displayed equation with cursor
somewhere at top-level is handled correctly.
The math-display lfun operates at top level in the math inset.
Therefore, when the cursor is in an inner inset, it will after the
lfun be moved at top level. Unfortunately, there is no way that I know
f to detect this in Inset::doDispatch.
Even if we could, as things stand, it is difficult to keep the cursor in the
inner inset, especially if the inner inset moves : this happens for
example when moving from eqnarray to inline maths.
Therefore this fix is the best I can think of now.
Fixes part of bug #9664.
It turns out that it is always better using the copy of the MacroData
for updating the macro_ pointer to avoid problems related to the cursor
position.
This can happen when a macro is copied and then the document where
it is defined is closed. In this case, the macro survives in the
cut stack but the the buffer pointer is dangling.
The MacroData pointer is updated by MathData::metrics() which is not
called when selecting a math inset with instant preview for math on.
Thus, we have to update it in the copy constructor otherwise a crash
is almost assured when hitting Ctrl+C.
We only look once for the definition of the same macro, but we have
to always check its arguments when the same macro appears more than
once in a math inset. So, move earlier this check.
The strategy adopted in bc47054b had some drawbacks related to the way
instant preview snippets are generated. See the subthread starting at
http://www.mail-archive.com/lyx-devel@lists.lyx.org/msg187916.html
for details.
The strategy adopted in this commit is that of adding macro definitions
only for the macros actually used in a preview snippet, independently
of whether some macro was already used in a previous snippet. In this way
the snippets don't need to be changed according to whether they are
compiled as a whole or separately from each other. This fact was causing
the regeneration of a preview snippet whenever the cursor entered the
corresponding inset, even if the generated image would have not changed.
The problem of defining or redefining a macro is taken care by the
python scripts.
The FIXME is not needed, this is how StyleChanger and FracChanger work:
In the constructor, they change the state of the FontInfo, and in the
destructor the state is set back. Therefore, all code that needs the changed
state, needs to be executed while the objects do still exist.
The math parser could not handle multicolumn grids. This is a problem because
there is no true ERT in math (everything is parsed).
Now multicolumn cells are parsed correctly. The display is also somewhat OK,
but apart from that any multicolumn related UI is missing. Since the file
format change is now done the UI can be added at any later point. The most
important part of bug 396 is now fixed: tex2lyx does not create invalid .lyx
files anymore for formulas containing \multicolumn.
I updated the tex2lyx test cases that produce correct output. tex2lyx does
still produce invalid output for the test cases which are not updated because
of the previous format change.
Newer boost versions use complicated type traits for boost::next and
boost::prior, which do not work with the RandomAccessList iterators.
The long term solution is to use std::next and std::prev, for now supply
simple replacements for compilers that do not support C++11 yet.
This is still a hack, but a less dangerous one. The old code had a problem
if it was called from different threads, or if for some reason it would get
called recursively.
Avoid that \newcommand[x] definitions of math macros are pushed multiple
times to the preview loader.
Redefinitions (via \renewcommand[x]) are properly handled.
In the test case the crash occured in mathml export of the temporary buffer,
because the macro was updated, and because one of the used other macros was
not copied, the macro argument was detached. However, the underlying problem
of the crash was a broken ArgumentProxy::mathMacro_ reference which became
invalid each time the ownng MathMacro was copied. In the bug test case the
copying happened due to resizing a std::vector, but any other copy would have
created the same problem. The crash did not always happen, because sometimes
the old freed memory was not immediately reused, so the invalid reference did
still point to usable data.
The fix is easy: Convert ArgumentProxy::mathMacro_ to a pointer and update it
always after creating a copy of the owner. The pimpl of MathMacro from the
previous commit helps here to distinguish between the data that can be
automatically copied (in MathMacro::Private) and the cleanup that needs to be
done manually (in MathMacro). This way, the manual copy constructor and
assigment operator of MathMacro does not need to be touched if a new member is
added.
The expanded cells of a mathmacro were previously stored in an InsetMathSqrt.
This was only used as a container for the MathData object in the first cell
of the sqrt inset, which contained the actual expanded arguments.
Funny enough, the only place were the inset property of expanded_ was really
used cannot be seen in the diff. It was MathMacro::kerning(), and this usage
was wrong, since InsetMathSqrt::kerning() always returns 0. Threfore, using
the correct type (MathData) for expanded_ does not only make the code more
readable, gets rid of an unneeded dependency, but also fixes a bug: Now the
correct kerning is returned for expanded cells. Also, expanded_ and
definition_ use the same type now, which looks nicely symmetric.
Previously, things like [ name ] where exported for computer algebra systems.
Now, the expanded macros are exported, which may still be wrong, but now the
CAS has at least a chance to understand what was meant.
The computation of length on screen depend in particular of the computation of the size of an em. Many places of the code used to rely on the width of the M character, which is not really correct:
http://en.wikipedia.org/wiki/Em_%28typography%29
In digital typography, the best value to use is the point size of the font.
* Implement FontMetrics::em(), which returns the value in pixels of the EM unit.
Convert code to use it.
* Introduce Length::inPixel(MetricsBase const &), which takes the textwidth and em information from the MetricsBase object. Convert code to use it.
* Fix several places where Length::inPixel is used without a proper em value.
* add mathed_font_em() helper function. It should eventually be removed like some other functions in MathSupport.
* Add dummy implementation of FontMetrics to tex2lyx for linking purposes.
LyX did not display the limits of the big math operators defined by
stmaryrd.sty correctly. The reason for this was a missing check in
InsetMathSymbol::metrics(), where it is hardcoded which symbols use display
style limits and which symbols use inline limits. In an ideal world this
information would be contained explicitly in lib/symbols.
This should go to branch as well.
We have some math macros that exist only because LyX can display them easily,
but which require user preamble code. These commands should not appear in
autocompletion, they are only there to make the formulas of users who actually
need thgese symbols and know what to put into the preamble more beautiful.
This avoids invoking the insert space dialog instead of the math version. Thereafter, spaces are correctly inserted inside macro templates.
This is the last part of the fix to #9432.
Thanks to Scott for testing. If a macro is unknown (displayed in red), then
macro_ is 0. The LATTEST is now adjusted and works like in MathMacro::write()
where I stole it from.
The math icons for the symbol image in the math completer were hardcoded to the
command names. This is wrong for some icons for various reasons, e.g. the case
insensitivity of windows file systems. Therefore we have to use the replacement
list which is also used for the toolbar icons. Bug #3538 is not closed because
of this problem, but IMHO it has nothing to do with this bug, it is a more
general one.
Rename recordUndoFullDocument to recordUndoFullBuffer.
Separate the notion of recording changes to paragraphs and recording changes in buffer parameters.
Audit every user of recordUndoFullDocument and replace it with either recordUndoBufferParams or recordUndoFullBuffer. Add comments to identify remaining work.
The problem was that the conversion to plain text (which is used as an
intermediate step) requires for some insets a valid buffer pointer, but
insets in the cut stack do not have one. Now we use the same temp buffer
business as for copying to the external clipboard.
Actually I wanted to do that in cc87f8100 but forgot to adjust the original
solution completely. Now we do not search for an arbitrary latexkeys instance
which just happens to have the same name as the macro, but we only use the
symbol that was explicitly set for global macros.
This patch fixes a series of warnings like:
{{{
In file included from ../../master/src/mathed/InsetMathBoldSymbol.cpp:13:
In file included from ../../master/src/mathed/InsetMathBoldSymbol.h:15:
../../master/src/mathed/InsetMathNest.h:37:7: warning: 'lyx::InsetMathNest::metrics' hides overloaded virtual function [-Woverloaded-virtual]
void metrics(MetricsInfo const & mi) const;
^
../../master/src/insets/Inset.h:186:15: note: hidden overloaded virtual function 'lyx::Inset::metrics' declared here: different number of parameters
(2 vs 1)
virtual void metrics(MetricsInfo & mi, Dimension & dim) const = 0;
^
}}}
For a description of the problem, see for example:
http://stackoverflow.com/questions/18515183/c-overloaded-virtual-function-warning-by-clang
3 different strategies have been used:
* in frontend, some functions have been renamed.
* in InsetMath.h, Inset::write has been explicitly imported too
* in InsetMathNest.h, since a comment said that hiding Inset::metrics is intended, a special trick has bee used to silence the warning.
Thanks to Enrico, who noticed that the previous fix did not take into account
the case of nonempty length argument + the next line beginning with [.
Now the parsing is exactly the inverse of InsetMathGrid::eolString().
There was an unsymmetry between reading and writing: InsetMathGrid::eolString()
adds curly braces if the first cell of the next line starts with [ to prevent
misparsing as optional argument of \\. These braces were not removed on reading.
