Hagen - Pragma ADE

74
Features
}
}
This goodie file is only providing information about the meaning of a stylistic alternate.
These have abstract tags like ss01 and in this case this category collects alternative
italic (calligraphic) shapes. Because math does not follow the same rules as text, this
feature is enabled explicitly.
In the goodie file of Xits math the alternates table has more entries:
alternates = {
cal = { ... comment = "Mathematical Calligraphic Alphabet" },
greekssup = { ... comment = "Mathematical Greek Sans Serif Alphabet" },
greekssit = { ... comment = "Mathematical Italic Sans Serif Digits" },
monobfnum = { ... comment = "Mathematical Bold Monospace Digits" },
mathbbbf = { ... comment = "Mathematical Bold Double-Struck Alphabet" },
mathbbit = { ... comment = "Mathematical Italic Double-Struck Alphabet" },
mathbbbi = { ... comment = "Mathematical Bold Italic Double-Struck Alphabet" },
upint = { ... comment = "Upright Integrals" },
vertnot = { ... comment = "Negated Symbols With Vertical Stroke" },
}
An alternate is triggered at the T E X end with:
$ABC$ $\cal ABC$ $\mathalternate{cal}\cal ABC$
This is an example of a dynamic feature that gets applied when enabled at a specific
location in the input. The cal is only recognized when it is defined in a goodies file,
where the value is defined (in all of the above cases the value is 1).
The Xits math fonts has a goodie files that starts with:
return {
name = "xits-math",
version = "1.00",
comment = "Goodies that complement xits (by Khaled Hosny).",
author = "Hans Hagen",
copyright = "ConTeXt development team",
mathematics = {
italics = {
["xits-math"] = italics,
},
alternates = {
Here the italics variable is a table defined before the return that looks as follows:
local italics = {
defaultfactor = 0.025,