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comparison src/luan/interp/ConcatExpr.java @ 8:8896068e0a4b

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finish operators git-svn-id: https://luan-java.googlecode.com/svn/trunk@9 21e917c8-12df-6dd8-5cb6-c86387c605b9
author fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9>
date Wed, 21 Nov 2012 06:57:09 +0000
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children 8217d8485715
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7:bca8fc5d928b 8:8896068e0a4b
1 package luan.interp;
2
3 import luan.Lua;
4 import luan.LuaNumber;
5 import luan.LuaException;
6 import luan.LuaState;
7
8
9 final class ConcatExpr extends BinaryOpExpr {
10
11 ConcatExpr(Expr op1,Expr op2) {
12 super(op1,op2);
13 }
14
15 @Override Object eval(LuaState lua) throws LuaException {
16 Object v1 = op1.eval(lua);
17 Object v2 = op2.eval(lua);
18 check(v1);
19 check(v2);
20 return Lua.toString(v1) + Lua.toString(v2);
21 }
22
23 private static void check(Object v) throws LuaException {
24 if( !(v instanceof String || v instanceof LuaNumber) )
25 throw new LuaException( "attempt to concatenate a " + Lua.type(v) + " value" );
26 }
27 }