Replacement lookup

mauro sacchetto

I would like to implement a replacement lookup in a font instead of relying on the software. I explain the thing from the software point of view, since I am more expert in LaTeX than in fonts. The relevant part of code is as follows:

<div>\directlua{ </div><div>&nbsp; &nbsp;fonts.handlers.otf.addfeature{</div><div> &nbsp; &nbsp; name = "apo-nosc",</div><div> &nbsp; &nbsp; type = "chainsubstitution",</div><div> &nbsp; &nbsp; lookups = {</div><div> &nbsp; &nbsp; &nbsp; {</div><div> &nbsp; &nbsp; &nbsp; &nbsp; type = "substitution",</div><div> &nbsp; &nbsp; &nbsp; &nbsp; data = {</div><div> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ["quoteright.sc"] = "quoteright.fr",&nbsp;</div><div> &nbsp; &nbsp; &nbsp; &nbsp; },</div><div> &nbsp; &nbsp; &nbsp; },</div><div> &nbsp; &nbsp; },</div><div> &nbsp; &nbsp; data = {</div><div> &nbsp; &nbsp; &nbsp; rules = {</div><div> &nbsp; &nbsp; &nbsp; &nbsp; {</div><div> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; before&nbsp; = { { "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"} },</div><div> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; current = { { "quoteright.sc" } },</div><div> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; lookups = { 1 },</div><div> &nbsp; &nbsp; &nbsp; &nbsp; },</div><div> &nbsp; &nbsp; &nbsp; },</div><div> &nbsp; &nbsp; },</div><div> &nbsp; }</div><div> }</div>When I write, for example, < \textsc{l'albero L'Albero} >, the first apostrophe is correctly rendered with the low apostrophe, that is with quoteright.sc. In the second case, the replacement rule for Luatex that I set replaces quoteright.sc with the high apostrophe, that is quoteright because the apostrophe is still between two capitals:

Is it possible to create a similar rule within the font that makes additional code in the text unnecessary?

And what should I adopt? A Contextual or Chaining Contextual Substitution?
Thank you

George Thomas

Are the two quotes intentionally at the same height? Because they are.

mauro sacchetto

ops... sorry, obviously not. This is the right image

Simon Cozens

mauro sacchetto said:

Is it possible to create a similar rule within the font that makes additional code in the text unnecessary?

Sure - that's "sub [A-Z] quoteright.sc' by quoteright.fr" in AFKDO Language, right?

And what should I adopt? A Contextual or Chaining Contextual Substitution?
Thank you

Does it matter? Implementations will often replace a contextual with a chaining contextual for generality.

John Hudson

You could also do this just by putting the /quoteright.sc/ in the c2sc but not in the smcp feature. That way, you could select the whole word and apply either just smcp or both smcp/c2sc to determine what gets converted to smallcaps.

mauro sacchetto

I managed to build a Contextual Alternates lookup that refers to a Single Substitution lookup: it works fine. The second solution is actually simpler. Is there reason to prefer one or the other, or are they equivalent?