public override bool TryOptimize(CompilerTarget target, out AstExpr expr)
{
expr = null;
var placeholders = Conditions.Count(AstPartiallyApplicable.IsPlaceholder);
for (var node = Conditions.First; node != null; node = node.Next)
{
var condition = node.Value;
_OptimizeNode(target, ref condition);
node.Value = condition; //Update list of conditions with optimized condition
PValue resultP;
if (condition is AstConstant &&
((AstConstant) condition).ToPValue(target).TryConvertTo(target.Loader,
PType.Bool, false, out resultP))
{
if ((bool) resultP.Value == ShortcircuitValue)
{
// Expr1 OP shortcircuit OP Expr2 = shortcircuit
// Expr1 OP shortcircuit OP Expr2 OP ? = const(shortcircuit)
var shortcircuitConst = new AstConstant(condition.File, condition.Line,
condition.Column, ShortcircuitValue);
if (placeholders > 0)
{
if (!Conditions.Last.Value.IsPlaceholder() || placeholders > 1)
_reportInvalidPlaceholders(target);
expr = shortcircuitConst.ConstFunc();
}
else
{
expr = shortcircuitConst;
}
return true;
}
else
{
// Expr1 OP ¬shortcircuit OP Expr2 = Expr1 OP Expr2
Conditions.Remove(node);
}
}
else if (condition is AstPlaceholder)
{
placeholders++;
}
}
if (Conditions.Count == 0)
{
expr = new AstConstant(File, Line, Column, !ShortcircuitValue);
}
else if (Conditions.Count == 1)
{
var primaryExpr = Conditions.First.Value;
expr = _GetOptimizedNode(target,
new AstTypecast(primaryExpr.File, primaryExpr.Line, primaryExpr.Column,
primaryExpr,
new AstConstantTypeExpression(primaryExpr.File,
primaryExpr.Line,
primaryExpr.Column,
PType.Bool.ToString())));
}
return expr != null;
}
