----------------------------------------------------------------------
assoc                                                       (hol88Lib)
----------------------------------------------------------------------
assoc : ''a -> (''a * 'b) list -> ''a * 'b

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

DESCRIBE
{assoc x [(x1,y1),...,(xn,yn)]} returns the first {(xi,yi)} in the list such
that {xi} equals {x}. The lookup is done on an eqtype, i.e., the SML
implementation must be able to decide equality for the type of {x}.

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

EXAMPLE

  - assoc 2 [(1,4),(3,2),(2,5),(2,6)];
 (2, 5) : (int * int)


COMMENTS
Superseded by {Lib.assoc} and {Lib.assoc1}.

SEEALSO
hol88Lib.rev_assoc, Lib.assoc, Lib.assoc1.

----------------------------------------------------------------------