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view src/luan/interp/UnmExpr.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 | 2a35154aec14 |
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package luan.interp; import luan.Lua; import luan.LuaNumber; import luan.LuaFunction; import luan.LuaException; // unary minus final class UnmExpr extends UnaryOpExpr { UnmExpr(Expr op) { super(op); } @Override public Object eval(LuaStateImpl lua) throws LuaException { Object o = op.eval(lua); LuaNumber n = Lua.toNumber(o); if( n != null ) return new LuaNumber( -n.value() ); LuaFunction fn = Utils.getHandler("__unm",o); if( fn != null ) return Utils.first(fn.call(lua,o)); throw new LuaException("attempt to perform arithmetic on a "+Lua.type(o)+" value"); } }