Mercurial > lasercutter

     1 /**

     2  *   Copyright (c) Rich Hickey. All rights reserved.

     3  *   The use and distribution terms for this software are covered by the

     4  *   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)

     5  *   which can be found in the file epl-v10.html at the root of this distribution.

     6  *   By using this software in any fashion, you are agreeing to be bound by

     7  * 	 the terms of this license.

     8  *   You must not remove this notice, or any other, from this software.

     9  **/

    10 

    11 /* rich Nov 2, 2009 */

    12 

    13 package clojure.lang;

    14 

    15 public final class KeywordLookupSite implements ILookupSite, ILookupThunk{

    16 

    17 final int n;

    18 final Keyword k;

    19 

    20 public KeywordLookupSite(int n, Keyword k){

    21 	this.n = n;

    22 	this.k = k;

    23 }

    24 

    25 public Object fault(Object target, ILookupHost host){

    26 	if(target instanceof IKeywordLookup)

    27 		{

    28 		return install(target, host);

    29 		}

    30 	else if(target instanceof ILookup)

    31 		{

    32 		host.swapThunk(n,ilookupThunk(target.getClass()));

    33 		return ((ILookup) target).valAt(k);

    34 		}

    35 	host.swapThunk(n,this);

    36 	return RT.get(target, k);

    37 }

    38 

    39 public Object get(Object target){

    40 	if(target instanceof IKeywordLookup || target instanceof ILookup)

    41 		return this;

    42 	return RT.get(target,k);

    43 }

    44 

    45 private ILookupThunk ilookupThunk(final Class c){

    46 	return new ILookupThunk(){

    47 			public Object get(Object target){

    48 				if(target != null && target.getClass() == c)

    49 					return ((ILookup) target).valAt(k);

    50 				return this;

    51 			}

    52 		};

    53 }

    54 

    55 private Object install(Object target, ILookupHost host){

    56 	ILookupThunk t = ((IKeywordLookup)target).getLookupThunk(k);

    57 	if(t != null)

    58 		{

    59 		host.swapThunk(n,t);

    60 		return t.get(target);

    61 		}

    62 	host.swapThunk(n,ilookupThunk(target.getClass()));

    63 	return ((ILookup) target).valAt(k);

    64 }

    65 }
author	Robert McIntyre <rlm@mit.edu>
date	Sat, 21 Aug 2010 06:25:44 -0400
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