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rev_assoc                                                        (Lib)
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rev_assoc : ''a -> ('b * ''a) list -> 'b

SYNOPSIS
Searches a list of pairs for a pair whose second component equals a specified
value.

KEYWORDS
list.

DESCRIBE
An invocation {rev_assoc y [(x1,y1),...,(xn,yn)]} locates
the first {(xi,yi)} in a left-to-right scan of the list such that
{yi} equals {y}. Then {xi} is returned. The lookup is done on an eqtype,
i.e., the SML implementation must be able to decide equality for the type
of {y}.

FAILURE
Fails if no matching pair is found. This will always be the case if the
list is empty.

EXAMPLE

- rev_assoc 2 [(1,4),(3,2),(2,5),(2,6)];
> val it = 3 : int




SEEALSO
Lib.assoc, Lib.assoc1, Lib.assoc2, Lib.mem, Lib.tryfind, Lib.exists,
Lib.all.

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