User Guide

Making OpenType Fonts
669
This sub-run represents the target sequences of the lookups called by this
rule. The lookup type of the lookup called by this rule is auto-detected from
their target and replacement sequences in the same way as in their
corresponding stand-alone (i.e. non-contextual) statements.
Example 1. This calls a lookup. The rule below means: in sequences "a d"
or "e d" or "n d", substitute "d" by "d.alt".
substitute [a e n] d' by d.alt;
Example 2. This also calls a single substitution lookup. The rule below
means: if a capital letter is followed by a small capital, then replace the
small capital by its corresponding lowercase letter.
substitute [A-Z] [Asmall-Zsmall]' by [a-z];
Example 3. This calls a ligature substitution lookup. The rule below
means: in sequences "e t c" or "e.begin t c", substitute the first two glyphs
by the ampersand.
substitute [e e.begin]' t' c by ampersand;