// The Nova Project by Ken Beckett.
// Copyright (C) 2007-2012 Inevitable Software, all rights reserved.
// Released under the Common Development and Distribution License, CDDL-1.0: http://opensource.org/licenses/cddl1.php
using Nova.Parsing;
using Nova.Rendering;
using Nova.Resolving;
namespace Nova.CodeDOM
{
/// <summary>
/// Represents one or more contraints on a type parameter.
/// </summary>
/// <remarks>
/// The constraints may consist of:
/// - a <see cref="ClassConstraint"/>
/// - a <see cref="StructConstraint"/>
/// - a <see cref="TypeConstraint"/> for a base class
/// - one or more <see cref="TypeConstraint"/>s for interfaces (which can also be generic)
/// - a <see cref="TypeConstraint"/> for a base class followed by one or more <see cref="TypeConstraint"/>s for interfaces
/// - a <see cref="TypeConstraint"/> for another <see cref="TypeParameter"/> (a "naked type constraint")
/// - a <see cref="NewConstraint"/> by itself or in addition to any of the above (must be at the end)
/// </remarks>
public class ConstraintClause : CodeObject
{
#region /* FIELDS */
protected SymbolicRef _typeParameter;
protected ChildList<TypeParameterConstraint> _constraints;
#endregion
#region /* CONSTRUCTORS */
/// <summary>
/// Create a <see cref="ConstraintClause"/>.
/// </summary>
public ConstraintClause(SymbolicRef symbolicRef, params TypeParameterConstraint[] constraints)
{
TypeParameter = symbolicRef;
CreateConstraints().AddRange(constraints);
}
/// <summary>
/// Create a <see cref="ConstraintClause"/>.
/// </summary>
public ConstraintClause(TypeParameterRef typeParameterRef, params TypeParameterConstraint[] constraints)
: this((SymbolicRef)typeParameterRef, constraints)
{ }
/// <summary>
/// Create a <see cref="ConstraintClause"/>.
/// </summary>
public ConstraintClause(TypeParameter typeParameter, params TypeParameterConstraint[] constraints)
: this(typeParameter.CreateRef(), constraints)
{ }
#endregion
#region /* PROPERTIES */
/// <summary>
/// The <see cref="TypeParameter"/> being constrained.
/// </summary>
public SymbolicRef TypeParameter
{
get { return _typeParameter; }
set { SetField(ref _typeParameter, value, true); }
}
/// <summary>
/// The list of <see cref="TypeParameterConstraint"/>s.
/// </summary>
public ChildList<TypeParameterConstraint> Constraints
{
get { return _constraints; }
}
#endregion
#region /* METHODS */
/// <summary>
/// Create the list of <see cref="TypeParameterConstraint"/>s, or return the existing one.
/// </summary>
public ChildList<TypeParameterConstraint> CreateConstraints()
{
if (_constraints == null)
_constraints = new ChildList<TypeParameterConstraint>(this);
return _constraints;
}
/// <summary>
/// Deep-clone the code object.
/// </summary>
public override CodeObject Clone()
{
ConstraintClause clone = (ConstraintClause)base.Clone();
clone.CloneField(ref clone._typeParameter, _typeParameter);
clone._constraints = ChildListHelpers.Clone(_constraints, clone);
return clone;
}
#endregion
#region /* PARSING */
/// <summary>
/// The token used to parse the code object.
/// </summary>
public const string ParseToken = "where";
/// <summary>
/// The token used to parse between the constraint type parameter and constraints.
/// </summary>
public const string ParseTokenSeparator = ":";
/// <summary>
/// Parse a <see cref="ConstraintClause"/>.
/// </summary>
public ConstraintClause(Parser parser, CodeObject parent)
: base(parser, parent)
{
// Get any regular comments from before the 'where'
MoveComments(parser.LastToken);
parser.NextToken(); // Move past 'where'
SetField(ref _typeParameter, UnresolvedRef.Create(parser.GetIdentifier()), false);
ParseExpectedToken(parser, ParseTokenSeparator); // Move past ':'
// Parse list of TypeParameterConstraints
while (true)
{
CreateConstraints().Add(TypeParameterConstraint.Parse(parser, this));
if (parser.TokenText == TypeParameterConstraint.ParseTokenSeparator)
parser.NextToken(); // Move past ','
else
break;
}
// Get the EOL comment from the Type expression of the last constraint if it's a TypeConstraint
// (it will end up there since they use an Expression), otherwise from the LastToken.
if (_constraints != null && _constraints.Last is TypeConstraint)
MoveEOLComment(((TypeConstraint)_constraints.Last).Type);
else
MoveEOLComment(parser.LastToken);
}
/// <summary>
/// Parse a list of constraint clauses.
/// </summary>
public static ChildList<ConstraintClause> ParseList(Parser parser, CodeObject parent)
{
ChildList<ConstraintClause> constraints = null;
while (parser.TokenText == ParseToken)
{
if (constraints == null)
constraints = new ChildList<ConstraintClause>(parent);
constraints.Add(new ConstraintClause(parser, parent));
}
return constraints;
}
#endregion
#region /* RESOLVING */
/// <summary>
/// Resolve all child symbolic references, using the specified <see cref="ResolveCategory"/> and <see cref="ResolveFlags"/>.
/// </summary>
public override CodeObject Resolve(ResolveCategory resolveCategory, ResolveFlags flags)
{
if (_typeParameter != null)
_typeParameter = (SymbolicRef)_typeParameter.Resolve(ResolveCategory.LocalTypeParameter, flags);
ChildListHelpers.Resolve(_constraints, ResolveCategory.CodeObject, flags);
return this;
}
/// <summary>
/// Returns true if the code object is an <see cref="UnresolvedRef"/> or has any <see cref="UnresolvedRef"/> children.
/// </summary>
public override bool HasUnresolvedRef()
{
if (ChildListHelpers.HasUnresolvedRef(_constraints))
return true;
if (_typeParameter != null && _typeParameter.HasUnresolvedRef())
return true;
return base.HasUnresolvedRef();
}
#endregion
#region /* FORMATTING */
/// <summary>
/// True if the code object defaults to starting on a new line.
/// </summary>
public override bool IsFirstOnLineDefault
{
get { return false; }
}
/// <summary>
/// Determines if the code object only requires a single line for display.
/// </summary>
public override bool IsSingleLine
{
get
{
return (base.IsSingleLine && (_typeParameter == null || (!_typeParameter.IsFirstOnLine && _typeParameter.IsSingleLine))
&& (_constraints == null || _constraints.Count == 0 || (!_constraints[0].IsFirstOnLine && _constraints.IsSingleLine)));
}
set
{
base.IsSingleLine = value;
if (value)
{
if (_typeParameter != null)
{
_typeParameter.IsFirstOnLine = false;
_typeParameter.IsSingleLine = true;
}
if (_constraints != null && _constraints.Count > 0)
{
_constraints[0].IsFirstOnLine = false;
_constraints.IsSingleLine = true;
}
}
}
}
#endregion
#region /* RENDERING */
public override void AsText(CodeWriter writer, RenderFlags flags)
{
int newLines = NewLines;
if (newLines > 0)
{
if (!flags.HasFlag(RenderFlags.SuppressNewLine))
writer.WriteLines(newLines);
}
else if (flags.HasFlag(RenderFlags.PrefixSpace))
writer.Write(" ");
flags &= ~RenderFlags.SuppressNewLine;
RenderFlags passFlags = (flags & RenderFlags.PassMask);
AsTextBefore(writer, passFlags | RenderFlags.IsPrefix);
UpdateLineCol(writer, flags);
// Increase the indent level for any newlines that occur within the statement if the flag is set
bool increaseIndent = flags.HasFlag(RenderFlags.IncreaseIndent);
if (increaseIndent)
writer.BeginIndentOnNewLine(this);
writer.Write(ParseToken);
RenderFlags noDescFlags = passFlags & ~(RenderFlags.Description | RenderFlags.ShowParentTypes);
if (_typeParameter != null)
_typeParameter.AsText(writer, noDescFlags | RenderFlags.IsPrefix | RenderFlags.PrefixSpace);
writer.Write(ParseTokenSeparator + " ");
writer.WriteList(_constraints, noDescFlags, this);
AsTextEOLComments(writer, flags);
if (increaseIndent)
writer.EndIndentation(this);
AsTextAfter(writer, passFlags | (flags & RenderFlags.NoPostAnnotations));
}
public static void AsTextConstraints(CodeWriter writer, ChildList<ConstraintClause> constraints, RenderFlags flags)
{
if (constraints != null && constraints.Count > 0)
writer.WriteList(constraints, flags | RenderFlags.NoItemSeparators | (constraints[0].IsFirstOnLine ? 0 : RenderFlags.PrefixSpace), constraints.Parent);
}
#endregion
}
}
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