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edited Feb 1, 2015 at 18:27

HoldPattern has attribute HoldAll

Attributes[HoldPattern]
(* {HoldAll, Protected} *)

So one can use the following injection

Cases[rules, HoldPattern[Alternatives@## -> _] & @@ targets]
(* {a -> 1, b -> 2} *)

P.S. Conceptually, HoldPattern is here the wrong tool for the job, even if this works. See Leonid's answer.

HoldPattern has attribute HoldAll

Attributes[HoldPattern]
(* {HoldAll, Protected} *)

So one can use the following injection

Cases[rules, HoldPattern[Alternatives@## -> _] & @@ targets]
(* {a -> 1, b -> 2} *)

HoldPattern has attribute HoldAll

Attributes[HoldPattern]
(* {HoldAll, Protected} *)

So one can use the following injection

Cases[rules, HoldPattern[Alternatives@## -> _] & @@ targets]
(* {a -> 1, b -> 2} *)

P.S. Conceptually, HoldPattern is here the wrong tool for the job, even if this works. See Leonid's answer.

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created Feb 1, 2015 at 17:59

HoldPattern has attribute HoldAll

Attributes[HoldPattern]
(* {HoldAll, Protected} *)

So one can use the following injection

Cases[rules, HoldPattern[Alternatives@## -> _] & @@ targets]
(* {a -> 1, b -> 2} *)