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view src/luan/LuanState.java @ 49:8ede219cd111
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git-svn-id: https://luan-java.googlecode.com/svn/trunk@50 21e917c8-12df-6dd8-5cb6-c86387c605b9
author | fschmidt@gmail.com <fschmidt@gmail.com@21e917c8-12df-6dd8-5cb6-c86387c605b9> |
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date | Fri, 28 Dec 2012 19:35:04 +0000 |
parents | 64ecb7a3aad7 |
children | 5c9cadd0acce |
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package luan; import java.io.InputStream; import java.io.PrintStream; import java.util.List; import java.util.ArrayList; public abstract class LuanState { private final LuanTable global = new LuanTable(); private final List<MetatableGetter> mtGetters = new ArrayList<MetatableGetter>(); final List<StackTraceElement> stackTrace = new ArrayList<StackTraceElement>(); public InputStream in = System.in; public PrintStream out = System.out; public PrintStream err = System.err; public final LuanTable global() { return global; } public final LuanTable getMetatable(Object obj) { if( obj instanceof LuanTable ) { LuanTable table = (LuanTable)obj; return table.getMetatable(); } for( MetatableGetter mg : mtGetters ) { LuanTable table = mg.getMetatable(obj); if( table != null ) return table; } return null; } public final void addMetatableGetter(MetatableGetter mg) { mtGetters.add(mg); } public Object[] call(LuanFunction fn,LuanElement calledFrom,String fnName,Object... args) throws LuanException { stackTrace.add( new StackTraceElement(calledFrom,fnName) ); try { return fn.call(this,args); } finally { stackTrace.remove(stackTrace.size()-1); } } public final String checkString(LuanElement el,Object obj) throws LuanException { String s = Luan.asString(obj); if( s == null ) throw new LuanException( this, el, "attempt to use a " + Luan.type(obj) + " as a string" ); return s; } public final Number checkNumber(LuanElement el,Object obj) throws LuanException { Number n = Luan.toNumber(obj); if( n == null ) throw new LuanException( this, el, "attempt to perform arithmetic on a " + Luan.type(obj) + " value" ); return n; } public final LuanFunction checkFunction(LuanElement el,Object obj) throws LuanException { if( obj instanceof LuanFunction ) return (LuanFunction)obj; throw new LuanException( this, el, "attempt to call a " + Luan.type(obj) + " value" ); } public final String toString(LuanElement el,Object obj) throws LuanException { LuanFunction fn = getHandlerFunction(el,"__tostring",obj); if( fn != null ) return checkString( el, Luan.first( call(fn,el,"__tostring",obj) ) ); if( obj == null ) return "nil"; if( obj instanceof Number ) return Luan.toString((Number)obj); if( obj instanceof LuanException ) { LuanException le = (LuanException)obj; return le.getMessage(); } return obj.toString(); } public final LuanFunction getHandlerFunction(LuanElement el,String op,Object obj) throws LuanException { Object f = getHandler(op,obj); if( f == null ) return null; return checkFunction(el,f); } public final Object getHandler(String op,Object obj) { LuanTable t = getMetatable(obj); return t==null ? null : t.get(op); } public final LuanFunction getBinHandler(LuanElement el,String op,Object o1,Object o2) throws LuanException { LuanFunction f1 = getHandlerFunction(el,op,o1); if( f1 != null ) return f1; return getHandlerFunction(el,op,o2); } public final boolean isLessThan(LuanElement el,Object o1,Object o2) throws LuanException { if( o1 instanceof Number && o2 instanceof Number ) { Number n1 = (Number)o1; Number n2 = (Number)o2; return n1.doubleValue() < n2.doubleValue(); } if( o1 instanceof String && o2 instanceof String ) { String s1 = (String)o1; String s2 = (String)o2; return s1.compareTo(s2) < 0; } LuanFunction fn = getBinHandler(el,"__lt",o1,o2); if( fn != null ) return Luan.toBoolean( Luan.first(call(fn,el,"__lt",o1,o2)) ); throw new LuanException( this, el, "attempt to compare " + Luan.type(o1) + " with " + Luan.type(o2) ); } }