internal static List<SchemeObject> lookupSymbolsFromEnv( ref SchemeAST currentAST, ISchemeEnvironment environment )
{
List<SchemeObject> ret = new List<SchemeObject>();
ret.Add( environment.get( (SchemeSymbol) currentAST.currentObject ) );
// not nice, but it works
/* if( ret[0] == null ) // this holds true if the currentObjcet is NOT in the symbol table. Then it might either be an integer or a float and has not been redefined or the function is unknown
{
ret.RemoveAt( 0 );
int intValue;
var symbol = ( (SchemeSymbol) currentAST.currentObject ).value;
if( int.TryParse( symbol, out intValue ) )
{
ret.Add( new SchemeInteger( intValue ) );
}
else //TODO extend for floats
{
throw new SchemeUndefinedSymbolException( String.Format( "Undefined Symbol: {0}", symbol ) );
}
} */
foreach (SchemeAST child in currentAST.children)
{
if( child.currentObject.GetType() == typeof( SchemeSymbol ) )
{
var symbol = (SchemeSymbol) child.currentObject;
ret.Add( environment.get( symbol ) );
if( ret[ret.Count -1]== null ) //objcet is not in symbol list, check for integer and float!
{
throw new SchemeUndefinedSymbolException( String.Format( "Undefined Symbol: {0}", symbol.value ) );
}
}
else
{
ret.Add( child.currentObject );
}
}
return ret;
}
private bool updateToNextLevelChild(ref SchemeAST currentAst, ISchemeEnvironment environment)
{
Type type = currentAst.currentObject.GetType();
if (type == typeof(SchemeSymbol))
{
SchemeType t = environment.get((SchemeSymbol)currentAst.currentObject);
if (t == null)
{
throw new SchemeUndefinedSymbolException(String.Format("Undefined Symbol: {0}", currentAst.currentObject.ToString()), currentAst.fileName, currentAst.sourceLength, currentAst.sourceOffset);
}
Type obj = t.GetType();
if (obj == typeof(SchemeBuiltInLambda)) // or typeof if. this is needed for parts which should not be evaluated.
{
return false;
}
if (obj == typeof(SchemeBuiltInIf))
{
var tmpRoot = new SchemeAST();
var condition = currentAst.children[0];
var oldParent = condition.parent;
tmpRoot.children.Add(condition);
condition.parent = tmpRoot;
var evaluated = evaluate(ref tmpRoot); //evaluate the if condition
tmpRoot = new SchemeAST(currentAst, evaluated[0]);
currentAst.children[0] = tmpRoot;
return false;
}
}
foreach (SchemeAST child in currentAst.children)
{
if (child.children.Count != 0)
{
currentAst = child;
return true;
}
}
return false;
}
private SchemeType getType(ref SchemeAST ast, ISchemeEnvironment environment)
{
SchemeObject ret = ast.currentObject;
if (ast.currentObject.GetType() == typeof(SchemeSymbol))
{
ret = environment.get((SchemeSymbol)ret);
}
if (!(ret is SchemeType))
{
return null;
}
return (SchemeType)ret;
}
private ISchemeFunction getFunction(ref SchemeAST ast, ISchemeEnvironment environment)
{
SchemeObject ret = ast.currentObject;
if (ast.currentObject.GetType() == typeof(SchemeSymbol))
{
ret = environment.get((SchemeSymbol)ret);
}
if (!(ret is ISchemeFunction))
{
return null;
}
return (ISchemeFunction)ret;
}
