Double quotation marks - special-characters

Question

I am trying to allow double quotation marks into my grammar's functions. I was hoping that I could use Haskell conventions to generate something like:
> mkSentence "This is \"just\" a sentence"
> This is "just" a sentence
However, when I try this in my grammar, I am faced with errors like in the example below using the English RGL:
> cc -table ss "This is \"just\" a sentence"
constant not found: just
given Predef, Predef, CatEng, ResEng, MorphoEng, Prelude,
ParadigmsEng
A function type is expected for ss "This is " instead of type {s : Str}
0 msec
> cc -table ss "This is \"just a sentence"
lexical error
0 msec
I can see that src/common/ExtendFunctor.gf in the RGL has an implementation of quoted:
oper
quoted : Str -> Str = \s -> "\"" ++ s ++ "\"" ; ---- TODO bind ; move to Prelude?
I have tried to implement something similar, but " may be used in different parts of my grammar, so ideally the double quotation marks could be escaped without special binds. I am considering defaulting to ” to avoid the issues with ", but maybe there is a way to escape double quotation marks "everywhere" (like in these docs)?
Any tips or reference to other docs would be very appreciated!

Answer 1

As far as I know, there is no API function for handling quotes. You can just do something like this yourself:
oper
qmark : Str = "\"" ;
quote : Str -> Str = \s -> qmark + s + qmark ;
And call it like this:
> cc -one ss ("This is" ++ quote "just" ++ "a sentence")
This is "just" a sentence
As long as you're only handling strings that are not runtime tokens, it works fine.
It's of course a bit clumsy to have to write it like that, but you can always write a sed oneliner from your preferred syntax. This works for just one "quoted" part, adjust as you wish for more.
$ sed -E 's/(.*) \\"(.*)\\" (.*)/("\1" ++ quote "\2" ++ "\3")/'
this is \"just\" a sentence
("this is" ++ quote "just" ++ "a sentence")
this is \"just\" a sentence with \"two\" quoted words
("this is \"just\" a sentence with" ++ quote "two" ++ "quoted words")