🚀 go-pugleaf

In article <25545@life.ai.mit.edu>, bkph@kauai.ai.mit.edu (Berthold K.P. Horn)
writes:
	Suppose there is a font that has a ligature --  ==>  endash

	Now suppose I have a keyboard that doesn't have a -, but does have a +
	key. So I decide to make + active and redefine it to generate the
	appropriate character code for minus, something like

	\catcode`\+=\active  \def+{\char45}

	Now I can type ++ and have it print endash, but...
	if a number follows the endash I am in trouble - for example:

	pp.~23++67

	`cause now TeX complains about bad character code since it expands
	into pp.~23\char4567  

	So I can add a \relax to the definition

	\catcode`\+=\active  \def+{\char45\relax}

	Now I don't get the complaint about bad character code, but the
	ligature doesn't work anymore!  What is the solution? (Assume that the
	character code of the desired character may actually be > 127, so that
	using the desired character in the definition isn`t an option).

Ligature substitution takes place very early, long before TeX can know the
\relax is a no-op.  For ligature substitution (or kerning) to take place, the
characters must be immediately adjacent.

There is, however, a simple way to do what you want.  Try:

	\def+{\char45 }

which works because a single space is discarded after a number.

							-- Jerry