6.42.3 Can you answer these questions?

6.42.3.1 Lua function that replaces strings, but ignores spaces and TeX comments

https://tex.stackexchange.com/landing/r/digest?cta=question&id=557091

I would like a Lua function for LuaTeX, called 
replaceButIgnoreSpacesAndComments (<string>, <what to replace>, <what to replace it by>) 
It is supposed to work like a string  ... 
[luatex] [strings] [lua]
 

asked by Gaussler https://tex.stackexchange.com/landing/r/digest?cta=user&id=19809 1 vote

6.42.3.2 Lettrine loversize causes Parallel text to be bottom aligned

https://tex.stackexchange.com/landing/r/digest?cta=question&id=556979

For some reason, using a lettrine with the optional loversize argument at the start of a ParallelLText or ParallelRText in a p-type Parallel environment causes the parallel text to be bottom-aligned  ... 
[xetex] [lettrine] [parallel]
                                                                                  

                                                                                  
 

asked by Andrew Ray https://tex.stackexchange.com/landing/r/digest?cta=user&id=212888 1 vote

6.42.3.3 Spacing and font in \frac

https://tex.stackexchange.com/landing/r/digest?cta=question&id=557113

When I write text in frac, it looks bad no space... bad font. How can I change it 
\documentclass{article} 
\begin{document} 
$ \frac{Lorem Ipsum}{abc dfe}$ 
\end{document} 
[math-mode]
 

asked by mathali https://tex.stackexchange.com/landing/r/digest?cta=user&id=221622 1 vote

answered by Henri Menke https://tex.stackexchange.com/landing/r/digest?cta=user&id=10995 0 votes