Mercurial Hosting > luan
diff src/luan/interp/LenExpr.java @ 7:bca8fc5d928b
work on expressions
git-svn-id: https://luan-java.googlecode.com/svn/trunk@8 21e917c8-12df-6dd8-5cb6-c86387c605b9
author | fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9> |
---|---|
date | Tue, 20 Nov 2012 10:06:27 +0000 |
parents | src/luan/interp/LengthExpr.java@7a2cdbc5767f |
children | b7d7069fee58 |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/luan/interp/LenExpr.java Tue Nov 20 10:06:27 2012 +0000 @@ -0,0 +1,31 @@ +package luan.interp; + +import luan.Lua; +import luan.LuaNumber; +import luan.LuaTable; +import luan.LuaException; +import luan.LuaState; + + +final class LenExpr extends UnaryOpExpr { + + LenExpr(Expr op) { + super(op); + } + + @Override Object eval(LuaState lua) throws LuaException { + return new LuaNumber( length(op.eval(lua)) ); + } + + 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" ); + } +}