Fix#4331. Parser treats TRUE/FALSE as functions rather than constants, which is nominally harmless, but it then expects an argument count of 0 and instead sees null-string. Changed to recognize this situation and leave TRUE/FALSE/TRUE()/FALSE() unchanged.
Fix#4129. Fix#4168. Html Writer, which all the Pdf writers use, defines its charts and drawings (henceforth I will just use charts for this discussion) using position:absolute and z-index. Browsers handle this correctly, but none of the Pdf writers do, and I can't think of an alternative method of styling them. The result is that the charts take up too much or too little room on the Pdf.
I suggested in the two discussions that treating the areas covered by the charts as merged cells might mitigate the problem. I think there are too many unknowns to do so automatically (and see next paragraph). However, adding to Spreadsheet new methods `mergeChartCellsForPdf` and `mergeDrawingCellsForPdf` allows the end user to do this if desired. The new methods are exercised for charts in samples/Chart/32_Chart_read_write_PDF, the results of which are much improved as a result. New samples/Pdf/21f_Drawing_mpdf does likewise for drawings.
The new methods alter the spreadsheet they are working on, which could be a problem if you still wish to work with the spreadsheet after writing it to Pdf. In that case, making a copy of the spreadsheet, then calling the new methods on the copy, and writing the copy to Pdf is probably best.
Custom properties would be better in this context using j (no leading 0) rather than d (leading 0) for day of month.
Properties has the same problem, and also needs backslashes before p to make it part of a <sup> tag.
The native preg functions (preg_match, preg_replace, etc.) often require us to add a lot of useless boilerplate code to satisfy Phpstan, Scrutinizer, etc. Composer/Pcre offers us a way to remove that boilerplate, thereby giving us a cleaner codebase. I decided to try it on a few modules, and saw a result that clearly demonstrated the usefulness of doing this (aside from the cleaner codebase).
Sample 22_Reader_issue1767 reads an Xlsx spreadsheet with complex sheet names used in defined names, and writes it to Xlsx and Xls output files. When I changed Writer/Xls/Parser to use Composer/Pcre, this sample failed in many different places writing the Xls file. It turns out that some regexes were failing not because the string didn't match, but because the regex encountered "catastrophic backtracing". Composer/Pcre throws an exception when this happens; the native preg_match does return false, but we were not checking for that. The regexes in question are now changed to something which works, and formal unit tests are added for them. Finding this previously undetected error indicates that we should proceed with this change.
An alternative to using Composer/Pcre would be to test for false after all the preg calls. I have done this in the two samples changed with this PR. That seems adequate for a small number of changes, but it really just makes for more clutter considering the large number of regexps that we use in our code. I think Composer/Pcre is a better choice.
It isn't quite transparent. Composer forces all regexps to use PREG_UNMATCHED_AS_NULL, so some match fields will now be null instead of null-string (or non-existent if the unmatched field comes at the end). Our test suite doesn't report any problem (yet) due to this change, although Phpstan is sensitive to it. Several Phpstan annotations were eliminated due to this change, but some others are now needed.
It is not necessary to do this all at once. This PR addresses all the calls in Writer. I intend to address other components in several tickets.