While trying to correct a bug in the Algebra question type (see CONTRIB-5337) created by Roger Moore and that I have been maintaining for several years, I discovered something that I was not aware of.
- first, I don't know why (I suspect he wanted it to be more easily customizable), Roger has put the TeX fragment to display a multiplication in the lang pack defining
$string['multiply'] = '\\\\times';
This was a mistake because there should be only one escaped anti-slash not two.
But when I went to AMOS to see how translators had translated that string, I discovered that AMOS has removed all anti-slashes both in the English string on the left and on the translated string on the right and that it was in fact not possible to enter a translation containing any anti-slash.
Of course it was easy to fix the problem by removing the string from the lang file and hard-coding the TeX fragment in the code (as it was done for all other TeX fragments). I just published a corrected version of the qtype_algebra plugin.
But I want to know if this AMOS feature is documented somewhere and if there are other forbidden characters in language strings. Do somebody know the answer to this question ?