/// <summary>
/// Deep-clone the code object.
/// </summary>
public override CodeObject Clone()
{
Unrecognized clone = (Unrecognized)base.Clone();
clone._expressions = ChildListHelpers.Clone(_expressions, clone);
return(clone);
}
/// <summary>
/// Parse an expression, stopping when default terminators, or the specified terminators, or a higher-precedence
/// operator is encountered.
/// </summary>
/// <param name="parser">The parser object.</param>
/// <param name="parent">The parent object.</param>
/// <param name="isTopLevel">True if EOL comments can be associated with the expression during parsing - generally
/// true if the parent is a statement or expression list, but with some exceptions.</param>
/// <param name="terminator">Optional terminating characters (null if none).</param>
/// <param name="flags">Parsing flags.</param>
/// <returns>The parsed <see cref="Expression"/>.</returns>
public static Expression Parse(Parser parser, CodeObject parent, bool isTopLevel, string terminator, ParseFlags flags)
{
// Save the starting token of the expression for later
Token startingToken = parser.Token;
// Start a new Unused list in the parser
parser.PushUnusedList();
// Parse an expression, which can be in one of the following formats:
// - An identifier token, optionally followed by an operator (which is parsed only if precedence rules determine it should be)
// - An operator (which will itself look for previous and/or following expressions when parsed)
// - An open paren, expression, close paren sequence (handled by the installed parse-point above), optionally followed by an operator
// Any other sequence will cause parsing of the expression to cease.
// The expression will be terminated by any of ';,}]', or other specified terminator.
// Create a string of possible terminators (assuming 1 char terminators for now)
string terminators = Statement.ParseTokenTerminator + ParseTokenSeparator + Block.ParseTokenEnd + Index.ParseTokenEnd + terminator;
// Keep a reference to the last token so we can move any skipped non-EOL comments to the expression later
Token lastToken = parser.LastToken;
// Loop until EOF or we find a terminator, or for directive expressions stop if we find a comment or a token on a new line.
// NOTE: Keep this logic in sync with the 'if' statement further down in the loop that checks for termination.
while (parser.TokenText != null &&
(parser.TokenText.Length != 1 || terminators.IndexOf(parser.TokenText[0]) < 0) &&
(!parser.InDirectiveExpression || ((parser.LastToken.TrailingComments == null || parser.LastToken.TrailingComments.Count == 0) && !parser.Token.IsFirstOnLine)))
{
process_next:
bool skipTerminationCheck = false;
// Process the current token (will process operators)
CodeObject obj = parser.ProcessToken(parent, flags | ParseFlags.Expression);
if (obj != null)
{
// If we got something, save it for later.
// Don't move any EOL comments here - they should have already been processed.
if (obj is CompilerDirective)
{
// If we have a compiler directive, and there's a preceeding unused object, add it there
CodeObject lastUnusedCodeObject = parser.LastUnusedCodeObject;
if (lastUnusedCodeObject != null && !(lastUnusedCodeObject is CompilerDirective))
{
lastUnusedCodeObject.AttachAnnotation((CompilerDirective)obj, AnnotationFlags.IsPostfix);
}
else
{
parser.AddUnused(obj); // Add the object to the unused list
skipTerminationCheck = true;
}
}
else
{
obj.ParseUnusedAnnotations(parser, parent, true); // Parse any annotations from the Unused list
parser.AddUnused(obj); // Add the object to the unused list
}
}
// Stop if EOF or we find a terminator, or for directive expressions stop if we find a comment or a token on a new line.
// NOTE: Keep this logic in sync with that in the condition of the parent 'while' loop.
if (parser.TokenText == null ||
(parser.TokenText.Length == 1 && terminators.IndexOf(parser.TokenText[0]) >= 0) ||
(parser.InDirectiveExpression && ((parser.LastToken.TrailingComments != null && parser.LastToken.TrailingComments.Count != 0) || parser.Token.IsFirstOnLine)))
{
// Don't abort here on a '{' terminator if we're in a doc comment and we appear to have type arguments using
// braces (as opposed to an Initializer after a NewObject). Go process the next object immediately instead.
if (parser.InDocComment && parser.TokenText == TypeRefBase.ParseTokenAltArgumentStart && parser.HasUnusedIdentifier &&
TypeRefBase.PeekTypeArguments(parser, TypeRefBase.ParseTokenAltArgumentEnd, flags))
{
goto process_next;
}
break;
}
// If the current token is the start of a compiler directive, check for special situations in which we want to skip
// the termination check below. This allows the directive to be attached to preceeding code objects such as literals
// or operators, while not attaching to simple name or type expressions which might be part of a namespace or type header.
if (parser.TokenText == CompilerDirective.ParseToken)
{
CodeObject lastUnusedCodeObject = parser.LastUnusedCodeObject;
if (lastUnusedCodeObject is Literal || lastUnusedCodeObject is Operator)
{
skipTerminationCheck = true;
// Also, capture any pending trailing comments
if (obj != null)
{
obj.MoveCommentsAsPost(parser.LastToken);
}
}
}
// If we don't have a specific terminating character, then we're parsing a sub-expression and we should stop when we
// get to an invalid operator, or an operator of greater precedence. Skip this check if we just parsed a compiler
// directive and didn't have a preceeding code object to attach it to, or if we're about to parse a compiler directive
// and we have an unused code object that we'd like to attach it to.
if (terminator == null && !skipTerminationCheck)
{
// Check for '{' when used inside a doc comment in a generic type constructor or generic method instance
if (parser.InDocComment && parser.TokenText == TypeRefBase.ParseTokenAltArgumentStart &&
TypeRefBase.PeekTypeArguments(parser, TypeRefBase.ParseTokenAltArgumentEnd, flags))
{
continue;
}
// Check if the current token represents a valid operator
Parser.OperatorInfo operatorInfo = parser.GetOperatorInfoForToken();
// If the current token doesn't look like a valid operator, we're done with the expression
if (operatorInfo == null)
{
break;
}
// We have an operator - check if our parent is also an operator
if (parent is Operator)
{
// Special cases for Types: Some operator symbols are overloaded and can also be part
// of a type name. We must detect these here, and continue processing in these cases,
// skipping the operator precedence checks below that terminate the current expression.
// Check for '[' when used in an array type name
if (parser.TokenText == TypeRefBase.ParseTokenArrayStart && TypeRefBase.PeekArrayRanks(parser))
{
continue;
}
// Check for '<' when used in a generic type constructor or generic method instance
if (parser.TokenText == TypeRefBase.ParseTokenArgumentStart && TypeRefBase.PeekTypeArguments(parser, TypeRefBase.ParseTokenArgumentEnd, flags))
{
continue;
}
// Do NOT check for '?' used for nullable types, because it applies to the entire
// expression on the left, so we DO want to terminate processing.
// Determine the precedence of the parent operator
// NOTE: See the bottom of Operator.cs for a quick-reference of operator precedence.
int parentPrecedence = ((Operator)parent).GetPrecedence();
// Stop parsing if the parent operator has higher precedence
if (parentPrecedence < operatorInfo.Precedence)
{
break;
}
// If the parent has the same precedence, stop parsing if the operator is left-associative
if (parentPrecedence == operatorInfo.Precedence && operatorInfo.LeftAssociative)
{
break;
}
}
}
}
// Get the expression
Expression expression = parser.RemoveLastUnusedExpression();
if (expression != null)
{
// Attach any skipped non-EOL comments from the front of the expression, but only if we're a top-level expression
// (otherwise, comments that preceed a sub-expression will get attached to an outer expression instead). This
// prevents lost comments in places such as between a 'return' and the expression that follows.
if (isTopLevel)
{
expression.MoveAllComments(lastToken);
}
// If this is a top-level expression or if the next token is a close paren, move any trailing comments on the last
// token of the expression as post comments. This prevents lost comments in places such as when some trailing parts of
// an 'if' conditional expression are commented-out, or the trailing parts of any sub-expression before a close paren.
if ((isTopLevel || parser.TokenText == ParseTokenEndGroup) && parser.LastToken.HasTrailingComments && !parser.InDirectiveExpression)
{
expression.MoveCommentsAsPost(parser.LastToken);
}
}
// Flush remaining unused objects as Unrecognized objects
while (parser.HasUnused)
{
Expression preceedingUnused = parser.RemoveLastUnusedExpression(true);
if (preceedingUnused != null)
{
if (expression == null)
{
expression = new Unrecognized(false, parser.InDocComment, preceedingUnused);
}
else if (expression is Unrecognized && !expression.HasParens)
{
((Unrecognized)expression).AddLeft(preceedingUnused);
}
else
{
expression = new Unrecognized(false, parser.InDocComment, preceedingUnused, expression);
}
}
else
{
// If we have no expression to put them on, then parse any preceeding compiler directives into a temp object for later retrieval
if (expression == null)
{
expression = new TempExpr();
}
expression.ParseUnusedAnnotations(parser, parent, true);
break;
}
}
if (expression is Unrecognized)
{
((Unrecognized)expression).UpdateMessage();
}
parser.Unused.Clear();
// Restore the previous Unused list in the parser
parser.PopUnusedList();
if (expression != null)
{
// Get any EOL comments
if (parser.LastToken.HasTrailingComments)
{
expression.MoveEOLComment(parser.LastToken);
}
// Set the parent starting token to the beginning of the expression
parser.ParentStartingToken = startingToken;
}
return(expression);
}
