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comparison src/luan/interp/IndexExpr.java @ 35:e51906de0f11

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implement metatables git-svn-id: https://luan-java.googlecode.com/svn/trunk@36 21e917c8-12df-6dd8-5cb6-c86387c605b9
author fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9>
date Tue, 18 Dec 2012 07:05:58 +0000
parents
children 2a35154aec14
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34:0cdc1da466ee 35:e51906de0f11
1 package luan.interp;
2
3 import luan.Lua;
4 import luan.LuaException;
5 import luan.LuaTable;
6 import luan.LuaFunction;
7
8
9 final class IndexExpr extends BinaryOpExpr {
10
11 IndexExpr(Expr op1,Expr op2) {
12 super(op1,op2);
13 }
14
15 @Override public Object eval(LuaStateImpl lua) throws LuaException {
16 return index(lua,op1.eval(lua),op2.eval(lua));
17 }
18
19 private static Object index(LuaStateImpl lua,Object t,Object key) throws LuaException {
20 Object h;
21 if( t instanceof LuaTable ) {
22 LuaTable tbl = (LuaTable)t;
23 Object value = tbl.get(key);
24 if( value != null )
25 return value;
26 h = Utils.getHandlerObject("__index",t);
27 if( h==null )
28 return null;
29 } else {
30 h = Utils.getHandlerObject("__index",t);
31 if( h==null )
32 throw new LuaException( "attempt to index a " + Lua.type(t) + " value" );
33 }
34 if( h instanceof LuaFunction ) {
35 LuaFunction fn = (LuaFunction)h;
36 return Utils.first(fn.call(lua,t,key));
37 }
38 return index(lua,h,key);
39 }
40 }