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view src/luan/interp/ConcatExpr.java @ 35:e51906de0f11
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> |
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date | Tue, 18 Dec 2012 07:05:58 +0000 |
parents | 5cf15507d77e |
children | 8a57ebfdfd78 |
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package luan.interp; import luan.Lua; import luan.LuaFunction; import luan.LuaException; final class ConcatExpr extends BinaryOpExpr { ConcatExpr(Expr op1,Expr op2) { super(op1,op2); } @Override public Object eval(LuaStateImpl lua) throws LuaException { Object o1 = op1.eval(lua); Object o2 = op2.eval(lua); String s1 = Lua.asString(o1); String s2 = Lua.asString(o2); if( s1 != null && s2 != null ) return s1 + s2; LuaFunction fn = getBinHandler("__concat",o1,o2); if( fn != null ) return Utils.first(fn.call(lua,o1,o2)); String type = s1==null ? Lua.type(o1) : Lua.type(o2); throw new LuaException( "attempt to concatenate a " + type + " value" ); } }