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diff src/luan/interp/LengthExpr.java @ 2:4da26b11d12a
start interp
git-svn-id: https://luan-java.googlecode.com/svn/trunk@3 21e917c8-12df-6dd8-5cb6-c86387c605b9
author | fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9> |
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date | Wed, 14 Nov 2012 08:53:25 +0000 |
parents | |
children | 7a2cdbc5767f |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/luan/interp/LengthExpr.java Wed Nov 14 08:53:25 2012 +0000 @@ -0,0 +1,30 @@ +package luan.interp; + +import luan.Lua; +import luan.LuaNumber; +import luan.LuaTable; +import luan.LuaException; + + +final class LengthExpr extends UnaryOpExpr { + + LengthExpr(Expr op) { + super(op); + } + + @Override Object eval() throws LuaException { + return new LuaNumber( length(op.eval()) ); + } + + private static int length(Object obj) throws LuaException { + if( obj instanceof String ) { + String s = (String)obj; + return s.length(); + } + if( obj instanceof LuaTable ) { + LuaTable t = (LuaTable)obj; + return t.length(); + } + throw new LuaException( "attempt to get length of a " + Lua.type(obj) + " value" ); + } +}