Removes an abbreviation from a goal’s assumptions by substituting it
out.
DESCRIPTION
The argument to UNABBREV_TAC must be a quotation containing the name
of a variable that is abbreviated in the current goal. In other
words, when calling UNABBREV_TAC `v`, there must be an assumption of
the form Abbrev(v = e) in the goal’s assumptions. This assumption
is removed, and all occurrences of the variable v in the goal are
replaced by e. If there are two abbreviation assumptions for v
in the goal, the more recent is removed.
EXAMPLE
The goal
Abbrev(v = 2 * x + 1), v + x < 10 ?- P(v)
is transformed by Q.UNABBREV_TAC `v` to
2 * x + 1 + x < 10 ?- P(2 * x + 1)
FAILURE
Fails if there is no abbreviation of the required form in the goal’s
assumptions, or if the quotation doesn’t parse to a variable.