Grammarcells: SubstituteCell does not work with n-ary expressions

[danielratiu]

I created an n-ary expression hierarchy and defined the editor using grammar-cells as shown in the attached screenshot. When I try to generate code for the editor definition, MPS produces a generation error (second screenshot).

I have also attached the language reproducing this error. grammar_cells_error.zip

[danielratiu]

I found a fix for this and committed it on the branch bugfix/#1997

@slisson please check if my fix is OK, if yes then please merge into master

[slisson]

Child collections are currently not supported by the parser. Using ChildSymbol in the generator is not valid, because it is for child links with 0..1/1 cardinality only.

[danielratiu]

@slisson thank you for the feedback. I do not understand the grammarcells framework good enough to extend ChildSymbol to deal with links with multiple cardinalities.

IMO being able to substitute N-ary expressions would be very useful ...