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     1 ;;  Copyright (c) Jason Wolfe. All rights reserved.  The use and

     2 ;;  distribution terms for this software are covered by the Eclipse Public

     3 ;;  License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can

     4 ;;  be found in the file epl-v10.html at the root of this distribution.  By

     5 ;;  using this software in any fashion, you are agreeing to be bound by the

     6 ;;  terms of this license.  You must not remove this notice, or any other,

     7 ;;  from this software.

     8 ;;

     9 ;;  map_utils.clj

    10 ;;

    11 ;;  Utilities for operating on Clojure maps.

    12 ;;

    13 ;;  jason at w01fe dot com

    14 ;;  Created 25 Feb 2009

    15 

    16 (ns 

    17   ^{:author "Jason Wolfe, Chris Houser",

    18      :doc "Utilities for operating on Clojure maps."}

    19   clojure.contrib.map-utils)

    20 

    21 

    22 (defmacro lazy-get 

    23   "Like get, but doesn't evaluate not-found unless it is needed."

    24   [map key not-found]

    25   `(if-let [pair# (find ~map ~key)] 

    26        (val pair#)

    27      ~not-found))

    28 

    29 (defn safe-get 

    30   "Like get, but throws an exception if the key is not found."

    31   [map key] 

    32   (lazy-get map key 

    33    (throw (IllegalArgumentException. (format "Key %s not found in %s" key map)))))

    34 

    35 (defn safe-get-in 

    36   "Like get-in, but throws an exception if any key is not found."

    37   [map ks]

    38   (reduce safe-get map ks))

    39 

    40 ; by Chouser:

    41 (defn deep-merge-with

    42   "Like merge-with, but merges maps recursively, applying the given fn

    43   only when there's a non-map at a particular level.

    44 

    45   (deepmerge + {:a {:b {:c 1 :d {:x 1 :y 2}} :e 3} :f 4}

    46                {:a {:b {:c 2 :d {:z 9} :z 3} :e 100}})

    47   -> {:a {:b {:z 3, :c 3, :d {:z 9, :x 1, :y 2}}, :e 103}, :f 4}"

    48   [f & maps]

    49   (apply

    50     (fn m [& maps]

    51       (if (every? map? maps)

    52         (apply merge-with m maps)

    53         (apply f maps)))

    54     maps))

    55
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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