source: branches/CodeEditor/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/IndentEngine/IndentState.cs @ 11700

//
// IndentState.cs
//
// Author:
//       Matej Miklečić <matej.miklecic@gmail.com>
//
// Copyright (c) 2013 Matej Miklečić (matej.miklecic@gmail.com)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

namespace ICSharpCode.NRefactory.CSharp
{
  #region IndentState

  /// <summary>
  ///     The base class for all indentation states. 
  ///     Each state defines the logic for indentation based on chars that
  ///     are pushed to it.
  /// </summary>
  public abstract class IndentState : ICloneable
  {
    #region Properties

    /// <summary>
    ///     The indentation engine using this state.
    /// </summary>
    public CSharpIndentEngine Engine;

    /// <summary>
    ///     The parent state. 
    ///     This state can use the indentation levels of its parent.
    ///     When this state exits, the engine returns to the parent.
    /// </summary>
    public IndentState Parent;

    /// <summary>
    ///     The indentation of the current line.
    ///     This is set when the state is created and will be changed to
    ///     <see cref="NextLineIndent"/> when the <see cref="CSharpIndentEngine.newLineChar"/> 
    ///     is pushed.
    /// </summary>
    public Indent ThisLineIndent;

    /// <summary>
    ///     The indentation of the next line.
    ///     This is set when the state is created and can change depending
    ///     on the pushed chars.
    /// </summary>
    public Indent NextLineIndent;

    #endregion

    #region Constructors

    protected IndentState()
    {
    }

    /// <summary>
    ///     Creates a new indentation state that is a copy of the given
    ///     prototype.
    /// </summary>
    /// <param name="prototype">
    ///     The prototype state.
    /// </param>
    /// <param name="engine">
    ///     The engine of the new state.
    /// </param>
    protected IndentState(IndentState prototype, CSharpIndentEngine engine)
    {
      Engine = engine;
      Parent = prototype.Parent != null ? prototype.Parent.Clone(engine) : null;

      ThisLineIndent = prototype.ThisLineIndent.Clone();
      NextLineIndent = prototype.NextLineIndent.Clone();
    }

    #endregion

    #region IClonable

    object ICloneable.Clone()
    {
      return Clone(Engine);
    }

    public abstract IndentState Clone(CSharpIndentEngine engine);

    #endregion

    #region Methods

    internal void Initialize (CSharpIndentEngine engine, IndentState parent = null)
    {
      Parent = parent;
      Engine = engine;

      InitializeState();
    }

    /// <summary>
    ///     Initializes the state:
    ///       - sets the default indentation levels.
    /// </summary>
    /// <remarks>
    ///     Each state can override this method if it needs a different
    ///     logic for setting up the default indentations.
    /// </remarks>
    public virtual void InitializeState()
    {
      ThisLineIndent = new Indent(Engine.textEditorOptions);
      NextLineIndent = ThisLineIndent.Clone();
    }

    /// <summary>
    ///     Actions performed when this state exits.
    /// </summary>
    public virtual void OnExit()
    {
      if (Parent != null)
      {
        // if a state exits on the newline character, it has to push
        // it back to its parent (and so on recursively if the parent 
        // state also exits). Otherwise, the parent state wouldn't
        // know that the engine isn't on the same line anymore.
        if (Engine.currentChar == Engine.newLineChar)
        {
          Parent.Push(Engine.newLineChar);
        }

        // when a state exits the engine stays on the same line and this
        // state has to override the Parent.ThisLineIndent.
        Parent.ThisLineIndent = ThisLineIndent.Clone();
      }
    }

    /// <summary>
    ///     Changes the current state of the <see cref="CSharpIndentEngine"/> using the current
    ///     state as the parent for the new one.
    /// </summary>
    /// <typeparam name="T">
    ///     The type of the new state. Must be assignable from <see cref="IndentState"/>.
    /// </typeparam>
    public void ChangeState<T>()
      where T : IndentState, new ()
    {
      var t = new T();
      t.Initialize(Engine, Engine.currentState);
      Engine.currentState = t;
    }

    /// <summary>
    ///     Exits this state by setting the current state of the
    ///     <see cref="CSharpIndentEngine"/> to this state's parent.
    /// </summary>
    public void ExitState()
    {
      OnExit();
      Engine.currentState = Engine.currentState.Parent ?? new GlobalBodyState(Engine);
    }

    /// <summary>
    ///     Common logic behind the push method.
    ///     Each state can override this method and implement its own logic.
    /// </summary>
    /// <param name="ch">
    ///     The current character that's being pushed.
    /// </param>
    public virtual void Push(char ch)
    {
      // replace ThisLineIndent with NextLineIndent if the newLineChar is pushed
      if (ch == Engine.newLineChar)
      {
        var delta = Engine.textEditorOptions.ContinuationIndent;
        while (NextLineIndent.CurIndent - ThisLineIndent.CurIndent > delta &&
             NextLineIndent.PopIf(IndentType.Continuation)) ;
        ThisLineIndent = NextLineIndent.Clone();
      }
    }

    /// <summary>
    ///     When derived, checks if the given sequence of chars form
    ///     a valid keyword or variable name, depending on the state.
    /// </summary>
    /// <param name="keyword">
    ///     A possible keyword.
    /// </param>
    public virtual void CheckKeyword(string keyword)
    { }

    /// <summary>
    ///     When derived, checks if the given sequence of chars form
    ///     a valid keyword or variable name, depending on the state.
    /// </summary>
    /// <param name="keyword">
    ///     A possible keyword.
    /// </param>
    /// <remarks>
    ///     This method should be called from <see cref="Push(char)"/>.
    ///     It is left to derived classes to call this method because of
    ///     performance issues.
    /// </remarks>
    public virtual void CheckKeywordOnPush(string keyword)
    { }

    #endregion
  }

  #endregion

  #region Null state

  /// <summary>
  ///     Null state.
  /// </summary>
  /// <remarks>
  ///     Doesn't define any transitions to new states.
  /// </remarks>
  public class NullState : IndentState
  {
    public NullState()
    { }

    public NullState(NullState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override void Push(char ch)
    { }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new NullState(this, engine);
    }
  }

  #endregion

  #region Brackets body states

  #region Brackets body base

  /// <summary>
  ///     The base for all brackets body states.
  /// </summary>
  /// <remarks>
  ///     Represents a block of code between a pair of brackets.
  /// </remarks>
  public abstract class BracketsBodyBaseState : IndentState
  {
  
    /// <summary>
    ///     When derived in a concrete bracket body state, represents
    ///     the closed bracket character pair.
    /// </summary>
    public abstract char ClosedBracket { get; }

    protected BracketsBodyBaseState()
    { }

    protected BracketsBodyBaseState(BracketsBodyBaseState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override void Push(char ch)
    {
      base.Push(ch);
      switch (ch) {
        case '#':
          if (Engine.isLineStart)
            ChangeState<PreProcessorState>();
          break;
        case '/':
          if (Engine.previousChar == '/')
            ChangeState<LineCommentState>();
          break;
        case '*':
          if (Engine.previousChar == '/')
            ChangeState<MultiLineCommentState>();
          break;
        case '"':
          if (Engine.previousChar == '@')
          {
            ChangeState<VerbatimStringState>();
          }
          else
          {
            ChangeState<StringLiteralState>();
          }
          break;
        case '\'':
          ChangeState<CharacterState>();
          break;
        case '{':
          ChangeState<BracesBodyState>();
          break;
        case '(':
          ChangeState<ParenthesesBodyState>();
          break;
        case '[':
          ChangeState<SquareBracketsBodyState>();
          break;
        default:
          if (ch == ClosedBracket)
            ExitState();
          break;
      }
    }
  }

  #endregion

  #region Braces body state

  /// <summary>
  ///     Braces body state.
  /// </summary>
  /// <remarks>
  ///     Represents a block of code between { and }.
  /// </remarks>
  public class BracesBodyState : BracketsBodyBaseState
  {
    /// <summary>
    ///     Type of the current block body.
    /// </summary>
    public Body CurrentBody;

    /// <summary>
    ///     Type of the next block body.
    ///     Same as <see cref="CurrentBody"/> if none of the
    ///     <see cref="Body"/> keywords have been read.
    /// </summary>
    public Body NextBody;

    /// <summary>
    ///     Type of the current statement.
    /// </summary>
    public Statement CurrentStatement
    {
      get
      {
        return currentStatement;
      }
      set
      {
        // clear NestedIfStatementLevels if this statement breaks the sequence
        if (currentStatement == Statement.None && value != Statement.Else)
        {
          NestedIfStatementLevels.Clear();
        }

        currentStatement = value;
      }
    }
    Statement currentStatement;

    /// <summary>
    ///    Contains indent levels of nested if statements.
    /// </summary>
    internal CloneableStack<Indent> NestedIfStatementLevels = new CloneableStack<Indent>();

    /// <summary>
    ///    Contains the indent level of the last statement or body keyword.
    /// </summary>
    public Indent LastBlockIndent;

    /// <summary>
    ///     True if the engine is on the right side of the equal operator '='.
    /// </summary>
    public bool IsRightHandExpression;

    /// <summary>
    ///     True if the '=' char has been pushed and it's not
    ///     a part of a relational operator (&gt;=, &lt;=, !=, ==).
    /// </summary>
    public bool IsEqualCharPushed;

    /// <summary>
    ///     The indentation of the previous line.
    /// </summary>
    public int PreviousLineIndent;

    /// <summary>
    ///     True if the dot member (e.g. method invocation) indentation has
    ///     been handled in the current statement.
    /// </summary>
    public bool IsMemberReferenceDotHandled;

    public override char ClosedBracket
    {
      get { return '}'; }
    }

    public BracesBodyState()
    {
    }

    public BracesBodyState(BracesBodyState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      CurrentBody = prototype.CurrentBody;
      NextBody = prototype.NextBody;
      CurrentStatement = prototype.CurrentStatement;
      NestedIfStatementLevels = prototype.NestedIfStatementLevels.Clone();
      IsRightHandExpression = prototype.IsRightHandExpression;
      IsEqualCharPushed = prototype.IsEqualCharPushed;
      IsMemberReferenceDotHandled = prototype.IsMemberReferenceDotHandled;
      LastBlockIndent = prototype.LastBlockIndent;
      PreviousLineIndent = prototype.PreviousLineIndent;
    }

    public override void Push(char ch)
    {
      // handle IsRightHandExpression property
      if (IsEqualCharPushed)
      {
        if (IsRightHandExpression)
        {
          if (ch == Engine.newLineChar)
          {
            NextLineIndent.RemoveAlignment();
            NextLineIndent.Push(IndentType.Continuation);
          }
        }
        // ignore "==" and "=>" operators
        else if (ch != '=' && ch != '>')
        {
          IsRightHandExpression = true;

          if (ch == Engine.newLineChar)
          {
            NextLineIndent.Push(IndentType.Continuation);
          }
          else
          {
            NextLineIndent.SetAlignment(Engine.column - NextLineIndent.CurIndent);
          }
        }

        IsEqualCharPushed = ch == ' ' || ch == '\t';
      }

      if (ch == ';' || (ch == ',' && IsRightHandExpression))
      {
        OnStatementExit();
      }
      else if (ch == '=' && !(Engine.previousChar == '=' || Engine.previousChar == '<' || Engine.previousChar == '>' || Engine.previousChar == '!'))
      {
        IsEqualCharPushed = true;
      }
      else if (ch == '.' && !IsMemberReferenceDotHandled)
      {
        // OPTION: CSharpFormattingOptions.AlignToMemberReferenceDot
        if (Engine.formattingOptions.AlignToMemberReferenceDot && !Engine.isLineStart)
        {
          IsMemberReferenceDotHandled = true;
          NextLineIndent.RemoveAlignment();
          NextLineIndent.SetAlignment(Engine.column - NextLineIndent.CurIndent - 1, true);
        }
        else if (Engine.isLineStart)
        {
          IsMemberReferenceDotHandled = true;

          ThisLineIndent.RemoveAlignment();
          while (ThisLineIndent.CurIndent > PreviousLineIndent && 
                 ThisLineIndent.PopIf(IndentType.Continuation)) ;
          ThisLineIndent.Push(IndentType.Continuation);
          NextLineIndent = ThisLineIndent.Clone();
        }
      }
      else if (ch == ':' && Engine.isLineStart && !IsRightHandExpression)
      {
        // try to capture ': base(...)', ': this(...)' and inherit statements when they are on a new line
        ThisLineIndent.Push(IndentType.Continuation);
      }
      else if (ch == Engine.newLineChar)
      {
        PreviousLineIndent = ThisLineIndent.CurIndent;
      }

      if (Engine.wordToken.ToString() == "else")
      {
        CheckKeywordOnPush("else");
      }

      base.Push(ch);
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = Parent.NextLineIndent.Clone();

      // OPTION: IDocumentIndentEngine.EnableCustomIndentLevels
      var parent = Parent as BracesBodyState;
      if (parent == null || parent.LastBlockIndent == null || !Engine.EnableCustomIndentLevels)
      {
        NextLineIndent.RemoveAlignment();
        NextLineIndent.PopIf(IndentType.Continuation);
      }
      else
      {
        NextLineIndent = parent.LastBlockIndent.Clone();
      }

      if (Engine.isLineStart)
      {
        ThisLineIndent = NextLineIndent.Clone();
      }

      CurrentBody = extractBody(Parent);
      NextBody = Body.None;
      CurrentStatement = Statement.None;

      AddIndentation(CurrentBody);
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new BracesBodyState(this, engine);
    }

    public override void OnExit()
    {
      if (Parent is BracesBodyState && !((BracesBodyState)Parent).IsRightHandExpression)
      {
        ((BracesBodyState)Parent).OnStatementExit();
      }

      if (Engine.isLineStart)
      {
        ThisLineIndent.RemoveAlignment();
        ThisLineIndent.PopTry();
        BraceStyle style;
        if (TryGetBraceStyle(this.CurrentBody, out style)) {
          if (style == BraceStyle.NextLineShifted ||
            style == BraceStyle.NextLineShifted2||
            style == BraceStyle.BannerStyle) {
            ThisLineIndent.Push(IndentType.Block);
          }
        }
      }

      base.OnExit();
    }

    /// <summary>
    ///     Actions performed when the current statement exits.
    /// </summary>
    public virtual void OnStatementExit()
    {
      IsRightHandExpression = false;
      IsMemberReferenceDotHandled = false;

      NextLineIndent.RemoveAlignment();
      NextLineIndent.PopWhile(IndentType.Continuation);

      CurrentStatement = Statement.None;
      NextBody = Body.None;
      LastBlockIndent = null;
    }

    #region Helpers

    /// <summary>
    ///     Types of braces bodies.
    /// </summary>
    public enum Body
    {
      None,
      Namespace,
      Class,
      Struct,
      Interface,
      Enum,
      Switch,
      Case,
      Try,
      Catch,
      Finally
    }

    /// <summary>
    ///     Types of statements.
    /// </summary>
    public enum Statement
    {
      None,
      If,
      Else,
      Do,
      While,
      For,
      Foreach,
      Lock,
      Using,
      Return
    }

    static readonly Dictionary<string, Body> bodies = new Dictionary<string, Body>
    {
      { "namespace", Body.Namespace },
      { "class", Body.Class },
      { "struct", Body.Struct },
      { "interface", Body.Interface },
      { "enum", Body.Enum },
      { "switch", Body.Switch },
      { "try", Body.Try },
      { "catch", Body.Catch },
      { "finally", Body.Finally },
    };

    static readonly Dictionary<string, Statement> statements = new Dictionary<string, Statement>
    {
      { "if", Statement.If },
      // { "else", Statement.Else }, // should be handled in CheckKeywordAtPush
      { "do", Statement.Do },
      { "while", Statement.While },
      { "for", Statement.For },
      { "foreach", Statement.Foreach },
      { "lock", Statement.Lock },
      { "using", Statement.Using },
      { "return", Statement.Return },
    };

    static readonly HashSet<string> blocks = new HashSet<string>
    {
      "namespace",
      "class",
      "struct",
      "interface",
      "enum",
      "switch",
      "try",
      "catch",
      "finally",
      "if",
      "else",
      "do",
      "while",
      "for",
      "foreach",
      "lock",
      "using",
    };

    readonly string[] caseDefaultKeywords = {
      "case",
      "default"
    };

    readonly string[] classStructKeywords = {
      "class",
      "struct"
    };

    /// <summary>
    ///     Checks if the given string is a keyword and sets the
    ///     <see cref="NextBody"/> and the <see cref="CurrentStatement"/>
    ///     variables appropriately.
    /// </summary>
    /// <param name="keyword">
    ///     A possible keyword.
    /// </param>
    /// <remarks>
    ///     This method is called from <see cref="Push(char)"/>
    /// </remarks>
    public override void CheckKeywordOnPush(string keyword)
    {
      if (keyword == "else")
      {
        CurrentStatement = Statement.Else;

        // OPTION: CSharpFormattingOptions.AlignElseInIfStatements
        if (!Engine.formattingOptions.AlignElseInIfStatements && NestedIfStatementLevels.Count > 0)
        {
          ThisLineIndent = NestedIfStatementLevels.Pop().Clone();
          NextLineIndent = ThisLineIndent.Clone();
        }

        NextLineIndent.Push(IndentType.Continuation);
      }

      if (blocks.Contains(keyword) && Engine.NeedsReindent)
      {
        LastBlockIndent = Indent.ConvertFrom(Engine.CurrentIndent, ThisLineIndent, Engine.textEditorOptions);
      }
    }

    /// <summary>
    ///     Checks if the given string is a keyword and sets the
    ///     <see cref="NextBody"/> and the <see cref="CurrentStatement"/>
    ///     variables appropriately.
    /// </summary>
    /// <param name="keyword">
    ///     A possible keyword.
    /// </param>
    public override void CheckKeyword(string keyword)
    {
      if (bodies.ContainsKey(keyword))
      {
        var isKeywordTemplateConstraint =
          classStructKeywords.Contains(keyword) &&
          (NextBody == Body.Class || NextBody == Body.Struct || NextBody == Body.Interface);

        if (!isKeywordTemplateConstraint)
        {
          NextBody = bodies[keyword];
        }
      }
      else if (caseDefaultKeywords.Contains(keyword) && CurrentBody == Body.Switch && Engine.isLineStartBeforeWordToken)
      {
        ChangeState<SwitchCaseState>();
      }
      else if (keyword == "where" && Engine.isLineStartBeforeWordToken)
      {
        // try to capture where (generic type constraint)
        ThisLineIndent.Push(IndentType.Continuation);
      }
      else if (statements.ContainsKey(keyword))
      {
        Statement previousStatement = CurrentStatement;
        CurrentStatement = statements[keyword];

        // return if this is a using declaration or alias
        if (CurrentStatement == Statement.Using &&
           (this is GlobalBodyState || CurrentBody == Body.Namespace))
        {
          return;
        }

        // OPTION: CSharpFormattingOptions.AlignEmbeddedIfStatements
        if (Engine.formattingOptions.AlignEmbeddedStatements &&
          previousStatement == Statement.If &&
          CurrentStatement == Statement.If)
        {
          ThisLineIndent.PopIf(IndentType.Continuation);
          NextLineIndent.PopIf(IndentType.Continuation);
        }

        // OPTION: CSharpFormattingOptions.AlignEmbeddedStatements
        if (Engine.formattingOptions.AlignEmbeddedStatements &&
          previousStatement == Statement.Lock &&
          CurrentStatement == Statement.Lock)
        {
          ThisLineIndent.PopIf(IndentType.Continuation);
          NextLineIndent.PopIf(IndentType.Continuation);
        }

        // OPTION: CSharpFormattingOptions.AlignEmbeddedUsingStatements
        if (Engine.formattingOptions.AlignEmbeddedStatements &&
          previousStatement == Statement.Using &&
          CurrentStatement == Statement.Using)
        {
          ThisLineIndent.PopIf(IndentType.Continuation);
          NextLineIndent.PopIf(IndentType.Continuation);
        }

        // only add continuation for 'else' in 'else if' statement.
        if (!(CurrentStatement == Statement.If && previousStatement == Statement.Else && !Engine.isLineStartBeforeWordToken))
        {
          NextLineIndent.Push(IndentType.Continuation);
        }

        if (CurrentStatement == Statement.If)
        {
          NestedIfStatementLevels.Push(ThisLineIndent);
        }
      }

      if (blocks.Contains(keyword) && Engine.NeedsReindent)
      {
        LastBlockIndent = Indent.ConvertFrom(Engine.CurrentIndent, ThisLineIndent, Engine.textEditorOptions);
      }
    }

    /// <summary>
    ///     Pushes a new level of indentation depending on the given
    ///     <paramref name="braceStyle"/>.
    /// </summary>
    void AddIndentation(BraceStyle braceStyle)
    {
      switch (braceStyle)
      {
        case BraceStyle.NextLineShifted:
          ThisLineIndent.Push(IndentType.Block);
          NextLineIndent.Push(IndentType.Block);
          break;
        case BraceStyle.DoNotChange:
        case BraceStyle.EndOfLine:
        case BraceStyle.EndOfLineWithoutSpace:
        case BraceStyle.NextLine:
        case BraceStyle.BannerStyle:
          NextLineIndent.Push(IndentType.Block);
          break;
        case BraceStyle.NextLineShifted2:
          ThisLineIndent.Push(IndentType.Block);
          NextLineIndent.Push(IndentType.DoubleBlock);
          break;
      }
    }

    bool TryGetBraceStyle (Body body, out BraceStyle style)
    {
      style = BraceStyle.DoNotChange;
      switch (body)
      {
        case Body.None:
          if (!Engine.formattingOptions.IndentBlocks)
            return false;
          style = Engine.formattingOptions.StatementBraceStyle;
          return true;
        case Body.Namespace:
          if (!Engine.formattingOptions.IndentNamespaceBody)
            return false;
          style = Engine.formattingOptions.NamespaceBraceStyle;
          return true;
        case Body.Class:
          if (!Engine.formattingOptions.IndentClassBody)
            return false;
          style = Engine.formattingOptions.ClassBraceStyle;
          return true;
        case Body.Struct:
          if (!Engine.formattingOptions.IndentStructBody)
            return false;
          style = Engine.formattingOptions.StructBraceStyle;
          return true;
        case Body.Interface:
          if (!Engine.formattingOptions.IndentInterfaceBody)
            return false;
          style = Engine.formattingOptions.InterfaceBraceStyle;
          return true;
        case Body.Enum:
          if (!Engine.formattingOptions.IndentEnumBody)
            return false;
          style = Engine.formattingOptions.EnumBraceStyle;
          return true;
        case Body.Switch:
          if (!Engine.formattingOptions.IndentSwitchBody)
            return false;
          style = Engine.formattingOptions.StatementBraceStyle;
          return true;
        case Body.Try:
        case Body.Catch:
        case Body.Finally:
          style = Engine.formattingOptions.StatementBraceStyle;
          return true;
      }
      return false;
    }

    /// <summary>
    ///     Pushes a new level of indentation depending on the given
    ///     <paramref name="body"/>.
    /// </summary>
    void AddIndentation(Body body)
    {
      var isExpression = Parent is ParenthesesBodyState || Parent is SquareBracketsBodyState ||
        (Parent is BracesBodyState && ((BracesBodyState)Parent).IsRightHandExpression);
      if (isExpression && Engine.formattingOptions.IndentBlocksInsideExpressions && Engine.isLineStart)
      {
        AddIndentation(BraceStyle.NextLineShifted);
      }

      BraceStyle style;
      if (TryGetBraceStyle(body, out style))
      {
        AddIndentation(style);
      } else {
        NextLineIndent.Push(IndentType.Empty);
      }
    }

    /// <summary>
    ///     Extracts the <see cref="CurrentBody"/> from the given state.
    /// </summary>
    /// <returns>
    ///     The correct <see cref="Body"/> type for this state.
    /// </returns>
    static Body extractBody(IndentState state)
    {
      if (state != null && state is BracesBodyState)
      {
        return ((BracesBodyState)state).NextBody;
      }

      return Body.None;
    }

    #endregion
  }

  #endregion

  #region Global body state

  /// <summary>
  ///     Global body state.
  /// </summary>
  /// <remarks>
  ///     Represents the global space of the program.
  /// </remarks>
  public class GlobalBodyState : BracesBodyState
  {
    public override char ClosedBracket
    {
      get { return '\0'; }
    }

    public GlobalBodyState()
    { }


    public GlobalBodyState(CSharpIndentEngine engine)
    {
      Initialize (engine, null);
    }

    public GlobalBodyState(GlobalBodyState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new GlobalBodyState(this, engine);
    }

    public override void InitializeState()
    {
      ThisLineIndent = new Indent(Engine.textEditorOptions);
      NextLineIndent = ThisLineIndent.Clone();
    }
  }

  #endregion

  #region Switch-case body state

  /// <summary>
  ///     Switch-case statement state.
  /// </summary>
  /// <remarks>
  ///     Represents the block of code in one switch case (including default).
  /// </remarks>
  public class SwitchCaseState : BracesBodyState
  {
    public SwitchCaseState()
    { }

    public SwitchCaseState(SwitchCaseState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override void Push(char ch)
    {
      // on ClosedBracket both this state (a case or a default statement)
      // and also the whole switch block (handled in the base class) must exit.
      if (ch == ClosedBracket)
      {
        ExitState();
        if (Parent is BracesBodyState)
          Parent.OnExit();
      }

      base.Push(ch);
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = ThisLineIndent.Clone();

      // remove all continuations and extra spaces
      ThisLineIndent.RemoveAlignment(); 
      ThisLineIndent.PopWhile(IndentType.Continuation);

      NextLineIndent.RemoveAlignment();
      NextLineIndent.PopWhile(IndentType.Continuation);

      if (Engine.formattingOptions.IndentCaseBody)
      {
        NextLineIndent.Push(IndentType.Block);
      }
      else
      {
        NextLineIndent.Push(IndentType.Empty);
      }
    }

    static readonly string[] caseDefaultKeywords = {
      "case",
      "default"
    };

    static readonly string[] breakContinueReturnGotoKeywords = {
      "break",
      "continue",
      "return",
      "goto"
    };

    public override void CheckKeyword(string keyword)
    {
      if (caseDefaultKeywords.Contains(keyword) && Engine.isLineStartBeforeWordToken)
      {
        ExitState();
        ChangeState<SwitchCaseState>();
      }
      else if (breakContinueReturnGotoKeywords.Contains(keyword) && Engine.isLineStartBeforeWordToken)
      {
        // OPTION: Engine.formattingOptions.IndentBreakStatements
        if (!Engine.formattingOptions.IndentBreakStatements)
        {
          ThisLineIndent = Parent.ThisLineIndent.Clone();
        }
      }

      base.CheckKeyword(keyword);
    }


    public override void OnExit()
    {
      //Parent.OnExit();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new SwitchCaseState(this, engine);
    }
  }

  #endregion

  #region Parentheses body state

  /// <summary>
  ///     Parentheses body state.
  /// </summary>
  /// <remarks>
  ///     Represents a block of code between ( and ).
  /// </remarks>
  public class ParenthesesBodyState : BracketsBodyBaseState
  {
    /// <summary>
    ///     True if any char has been pushed.
    /// </summary>
    public bool IsSomethingPushed;

    public override char ClosedBracket
    {
      get { return ')'; }
    }

    public ParenthesesBodyState()
    { }

    public ParenthesesBodyState(ParenthesesBodyState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsSomethingPushed = prototype.IsSomethingPushed;
    }

    public override void Push(char ch)
    {
      if (ch == Engine.newLineChar)
      {
        if (Engine.formattingOptions.AnonymousMethodBraceStyle == BraceStyle.EndOfLine || 
          Engine.formattingOptions.AnonymousMethodBraceStyle == BraceStyle.EndOfLineWithoutSpace) {
          if (NextLineIndent.PopIf(IndentType.Continuation)) {
            NextLineIndent.Push(IndentType.Block);
          }
        }
      }
      else if (!IsSomethingPushed)
      {
        // OPTION: CSharpFormattingOptions.AlignToFirstMethodCallArgument
        if (Engine.formattingOptions.AlignToFirstMethodCallArgument)
        {
          NextLineIndent.PopTry();
          // align the next line at the beginning of the open bracket
          NextLineIndent.ExtraSpaces = Math.Max(0, Engine.column - NextLineIndent.CurIndent - 1);
        }
      }

      base.Push(ch);
      IsSomethingPushed = true;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = ThisLineIndent.Clone();
      NextLineIndent.Push(IndentType.Continuation);
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new ParenthesesBodyState(this, engine);
    }

    public override void OnExit()
    {
      if (Engine.isLineStart)
      {
        if (ThisLineIndent.ExtraSpaces > 0)
        {
          ThisLineIndent.ExtraSpaces--;
        }
        else
        {
          ThisLineIndent.PopTry();
        }
      }

      base.OnExit();
    }
  }

  #endregion

  #region Square brackets body state

  /// <summary>
  ///     Square brackets body state.
  /// </summary>
  /// <remarks>
  ///     Represents a block of code between [ and ].
  /// </remarks>
  public class SquareBracketsBodyState : BracketsBodyBaseState
  {
    /// <summary>
    ///     True if any char has been pushed.
    /// </summary>
    public bool IsSomethingPushed;

    public override char ClosedBracket
    {
      get { return ']'; }
    }

    public SquareBracketsBodyState()
    { }

    public SquareBracketsBodyState(SquareBracketsBodyState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsSomethingPushed = prototype.IsSomethingPushed;
    }

    public override void Push(char ch)
    {
      if (ch == Engine.newLineChar)
      {
        if (NextLineIndent.PopIf(IndentType.Continuation))
        {
          NextLineIndent.Push(IndentType.Block);
        }
      }
      else if (!IsSomethingPushed)
      {
        // OPTION: CSharpFormattingOptions.AlignToFirstIndexerArgument
        if (Engine.formattingOptions.AlignToFirstIndexerArgument)
        {
          NextLineIndent.PopTry();
          // align the next line at the beginning of the open bracket
          NextLineIndent.ExtraSpaces = Math.Max(0, Engine.column - NextLineIndent.CurIndent - 1);
        }
      }

      base.Push(ch);
      IsSomethingPushed = true;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = ThisLineIndent.Clone();
      NextLineIndent.Push(IndentType.Continuation);
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new SquareBracketsBodyState(this, engine);
    }

    public override void OnExit()
    {
      if (Engine.isLineStart)
      {
        if (ThisLineIndent.ExtraSpaces > 0)
        {
          ThisLineIndent.ExtraSpaces--;
        }
        else
        {
          ThisLineIndent.PopTry();
        }
      }

      base.OnExit();
    }
  }

  #endregion

  #endregion

  #region PreProcessor state

  /// <summary>
  ///     PreProcessor directive state.
  /// </summary>
  /// <remarks>
  ///     Activated when the '#' char is pushed and the 
  ///     <see cref="CSharpIndentEngine.isLineStart"/> is true.
  /// </remarks>
  public class PreProcessorState : IndentState
  {
    /// <summary>
    ///     The type of the preprocessor directive.
    /// </summary>
    public PreProcessorDirective DirectiveType;

    /// <summary>
    ///     If <see cref="DirectiveType"/> is set (not equal to 'None'), this
    ///     stores the expression of the directive.
    /// </summary>
    public StringBuilder DirectiveStatement;

    public PreProcessorState()
    {
      DirectiveType = PreProcessorDirective.None;
      DirectiveStatement = new StringBuilder();
    }

    public PreProcessorState(PreProcessorState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      DirectiveType = prototype.DirectiveType;
      DirectiveStatement = new StringBuilder(prototype.DirectiveStatement.ToString());
    }

    public override void Push(char ch)
    {
      // HACK: if this change would be left for the CheckKeyword method, we will lose
      //       it if the next pushed char is newLineChar since ThisLineIndent will be 
      //       immediately replaced with NextLineIndent. As this most likely will
      //       happen, we check for "endregion" on every push.
      if (Engine.wordToken.ToString() == "endregion")
      {
        CheckKeywordOnPush("endregion");
      }

      base.Push(ch);

      if (DirectiveType != PreProcessorDirective.None)
      {
        DirectiveStatement.Append(ch);
      }

      if (ch == Engine.newLineChar)
      {
        ExitState();
        switch (DirectiveType)
        {
          case PreProcessorDirective.If:
            Engine.ifDirectiveEvalResults.Push(eval(DirectiveStatement.ToString()));
            if (Engine.ifDirectiveEvalResults.Peek())
            {
              // the if/elif directive is true -> continue with the previous state
            }
            else
            {
              // the if/elif directive is false -> change to a state that will 
              // ignore any chars until #endif or #elif
              ChangeState<PreProcessorCommentState>();
            }
            break;
          case PreProcessorDirective.Elif:
            if (Engine.ifDirectiveEvalResults.Count > 0)
            {
              if (!Engine.ifDirectiveEvalResults.Peek())
              {
                Engine.ifDirectiveEvalResults.Pop();
                goto case PreProcessorDirective.If;
              }
            }
            // previous if was true -> comment
            ChangeState<PreProcessorCommentState>();
            break;
          case PreProcessorDirective.Else:
            if (Engine.ifDirectiveEvalResults.Count > 0 && Engine.ifDirectiveEvalResults.Peek())
            {
              // some if/elif directive was true -> change to a state that will 
              // ignore any chars until #endif
              ChangeState<PreProcessorCommentState>();
            }
            else
            {
              // none if/elif directives were true -> continue with the previous state
            }
            break;
          case PreProcessorDirective.Define:
            var defineSymbol = DirectiveStatement.ToString().Trim();
            if (!Engine.conditionalSymbols.Contains(defineSymbol))
            {
              Engine.conditionalSymbols.Add(defineSymbol);
            }
            break;
          case PreProcessorDirective.Undef:
            var undefineSymbol = DirectiveStatement.ToString().Trim();
            if (Engine.conditionalSymbols.Contains(undefineSymbol))
            {
              Engine.conditionalSymbols.Remove(undefineSymbol);
            }
            break;
          case PreProcessorDirective.Endif:
            // marks the end of this block
            Engine.ifDirectiveEvalResults.Pop();
            Engine.ifDirectiveIndents.Pop();
            break;
          case PreProcessorDirective.Region:
          case PreProcessorDirective.Pragma:
          case PreProcessorDirective.Warning:
          case PreProcessorDirective.Error:
          case PreProcessorDirective.Line:
            // continue with the previous state
            break;
        }
      }
    }

    public override void InitializeState()
    {
      // OPTION: IndentPreprocessorStatements
      if (Engine.formattingOptions.IndentPreprocessorDirectives)
      {
        if (Engine.ifDirectiveIndents.Count > 0)
        {
          ThisLineIndent = Engine.ifDirectiveIndents.Peek().Clone();
        }
        else
        {
          ThisLineIndent = Parent.ThisLineIndent.Clone();
        }
      }
      else
      {
        ThisLineIndent = new Indent(Engine.textEditorOptions);
      }

      NextLineIndent = Parent.NextLineIndent.Clone();
    }

    static readonly Dictionary<string, PreProcessorDirective> preProcessorDirectives = new Dictionary<string, PreProcessorDirective>
    {
      { "if", PreProcessorDirective.If },
      { "elif", PreProcessorDirective.Elif },
      { "else", PreProcessorDirective.Else },
      { "endif", PreProcessorDirective.Endif },
      { "region", PreProcessorDirective.Region },
      { "endregion", PreProcessorDirective.Endregion },
      { "pragma", PreProcessorDirective.Pragma },
      { "warning", PreProcessorDirective.Warning },
      { "error", PreProcessorDirective.Error },
      { "line", PreProcessorDirective.Line },
      { "define", PreProcessorDirective.Define },
      { "undef", PreProcessorDirective.Undef }
    };

    public override void CheckKeywordOnPush(string keyword)
    {
      if (keyword == "endregion")
      {
        DirectiveType = PreProcessorDirective.Endregion;
        ThisLineIndent = Parent.NextLineIndent.Clone();
      }
    }

    public override void CheckKeyword(string keyword)
    {
      // check if the directive type has already been set
      if (DirectiveType != PreProcessorDirective.None)
      {
        return;
      }

      if (preProcessorDirectives.ContainsKey(keyword))
      {
        DirectiveType = preProcessorDirectives[keyword];

        // adjust the indentation for the region directive
        if (DirectiveType == PreProcessorDirective.Region)
        {
          ThisLineIndent = Parent.NextLineIndent.Clone();
        }
        else if (DirectiveType == PreProcessorDirective.If)
        {
          Engine.ifDirectiveIndents.Push(ThisLineIndent.Clone());
        }
      }
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new PreProcessorState(this, engine);
    }

    /// <summary>
    ///     Types of preprocessor directives.
    /// </summary>
    public enum PreProcessorDirective
    {
      None,
      If,
      Elif,
      Else,
      Endif,
      Region,
      Endregion,
      Pragma,
      Warning,
      Error,
      Line,
      Define,
      Undef
    }

    #region Pre processor evaluation (from cs-tokenizer.cs)

    static bool is_identifier_start_character(int c)
    {
      return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || Char.IsLetter((char)c);
    }

    static bool is_identifier_part_character(char c)
    {
      if (c >= 'a' && c <= 'z')
        return true;

      if (c >= 'A' && c <= 'Z')
        return true;

      if (c == '_' || (c >= '0' && c <= '9'))
        return true;

      if (c < 0x80)
        return false;

      return Char.IsLetter(c) || Char.GetUnicodeCategory(c) == UnicodeCategory.ConnectorPunctuation;
    }

    bool eval_val(string s)
    {
      if (s == "true")
        return true;
      if (s == "false")
        return false;

      return Engine.conditionalSymbols != null && Engine.conditionalSymbols.Contains(s) ||
        Engine.customConditionalSymbols != null && Engine.customConditionalSymbols.Contains(s);
    }

    bool pp_primary(ref string s)
    {
      s = s.Trim();
      int len = s.Length;

      if (len > 0)
      {
        char c = s[0];

        if (c == '(')
        {
          s = s.Substring(1);
          bool val = pp_expr(ref s, false);
          if (s.Length > 0 && s[0] == ')')
          {
            s = s.Substring(1);
            return val;
          }
          return false;
        }

        if (is_identifier_start_character(c))
        {
          int j = 1;

          while (j < len)
          {
            c = s[j];

            if (is_identifier_part_character(c))
            {
              j++;
              continue;
            }
            bool v = eval_val(s.Substring(0, j));
            s = s.Substring(j);
            return v;
          }
          bool vv = eval_val(s);
          s = "";
          return vv;
        }
      }
      return false;
    }

    bool pp_unary(ref string s)
    {
      s = s.Trim();
      int len = s.Length;

      if (len > 0)
      {
        if (s[0] == '!')
        {
          if (len > 1 && s[1] == '=')
          {
            return false;
          }
          s = s.Substring(1);
          return !pp_primary(ref s);
        }
        else
          return pp_primary(ref s);
      }
      else
      {
        return false;
      }
    }

    bool pp_eq(ref string s)
    {
      bool va = pp_unary(ref s);

      s = s.Trim();
      int len = s.Length;
      if (len > 0)
      {
        if (s[0] == '=')
        {
          if (len > 2 && s[1] == '=')
          {
            s = s.Substring(2);
            return va == pp_unary(ref s);
          }
          else
          {
            return false;
          }
        }
        else if (s[0] == '!' && len > 1 && s[1] == '=')
        {
          s = s.Substring(2);

          return va != pp_unary(ref s);

        }
      }

      return va;

    }

    bool pp_and(ref string s)
    {
      bool va = pp_eq(ref s);

      s = s.Trim();
      int len = s.Length;
      if (len > 0)
      {
        if (s[0] == '&')
        {
          if (len > 2 && s[1] == '&')
          {
            s = s.Substring(2);
            return (va & pp_and(ref s));
          }
          else
          {
            return false;
          }
        }
      }
      return va;
    }

    //
    // Evaluates an expression for `#if' or `#elif'
    //
    bool pp_expr(ref string s, bool isTerm)
    {
      bool va = pp_and(ref s);
      s = s.Trim();
      int len = s.Length;
      if (len > 0)
      {
        char c = s[0];

        if (c == '|')
        {
          if (len > 2 && s[1] == '|')
          {
            s = s.Substring(2);
            return va | pp_expr(ref s, isTerm);
          }
          else
          {

            return false;
          }
        }
        if (isTerm)
        {
          return false;
        }
      }

      return va;
    }

    bool eval(string s)
    {
      bool v = pp_expr(ref s, true);
      s = s.Trim();
      if (s.Length != 0)
      {
        return false;
      }

      return v;
    }

    #endregion
  }

  #endregion

  #region PreProcessorComment state

  /// <summary>
  ///     PreProcessor comment state.
  /// </summary>
  /// <remarks>
  ///     Activates when the #if or #elif directive is false and ignores
  ///     all pushed chars until the next '#'.
  /// </remarks>
  public class PreProcessorCommentState : IndentState
  {
    public PreProcessorCommentState()
    { }

    public PreProcessorCommentState(PreProcessorCommentState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == '#' && Engine.isLineStart)
      {
        // TODO: Return back only on #if/#elif/#else/#endif
        // Ignore any of the other directives (especially #define/#undef)
        ExitState();
        ChangeState<PreProcessorState>();
      }
    }

    public override void InitializeState()
    {
      if (Engine.formattingOptions.IndentPreprocessorDirectives &&
          Engine.ifDirectiveIndents.Count > 0)
      {
        ThisLineIndent = Engine.ifDirectiveIndents.Peek().Clone();
        NextLineIndent = ThisLineIndent.Clone();
      }
      else
      {
        ThisLineIndent = Parent.NextLineIndent.Clone();
        NextLineIndent = ThisLineIndent.Clone();
      }
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new PreProcessorCommentState(this, engine);
    }
  }

  #endregion

  #region LineComment state

  /// <summary>
  ///     Single-line comment state.
  /// </summary>
  public class LineCommentState : IndentState
  {
    /// <summary>
    ///     It's possible that this should be the DocComment state:
    ///         check if the first next pushed char is equal to '/'.
    /// </summary>
    public bool CheckForDocComment = true;

    public LineCommentState()
    {
      /*      if (engine.formattingOptions.KeepCommentsAtFirstColumn && engine.column == 2)
        ThisLineIndent.Reset();*/
    }

    public LineCommentState(LineCommentState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      CheckForDocComment = prototype.CheckForDocComment;
    }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == Engine.newLineChar)
      {
        // to handle cases like //\n/*
        // Otherwise line 2 would be treated as line comment.
        Engine.previousChar = '\0';
        ExitState();
      }
      else if (ch == '/' && CheckForDocComment)
      {
        // wrong state, should be DocComment.
        ExitState();
        ChangeState<DocCommentState>();
      }

      CheckForDocComment = false;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = Parent.NextLineIndent.Clone();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new LineCommentState(this, engine);
    }
  }

  #endregion

  #region DocComment state

  /// <summary>
  ///     XML documentation comment state.
  /// </summary>
  public class DocCommentState : IndentState
  {
    public DocCommentState()
    { }

    public DocCommentState(DocCommentState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    { }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == Engine.newLineChar)
      {
        ExitState();
      }
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = Parent.NextLineIndent.Clone();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new DocCommentState(this, engine);
    }
  }

  #endregion

  #region MultiLineComment state

  /// <summary>
  ///     Multi-line comment state.
  /// </summary>
  public class MultiLineCommentState : IndentState
  {
    /// <summary>
    ///     True if any char has been pushed to this state.
    /// </summary>
    /// <remarks>
    ///     Needed to resolve an issue when the first pushed char is '/'.
    ///     The state would falsely exit on this sequence of chars '/*/',
    ///     since it only checks if the last two chars are '/' and '*'.
    /// </remarks>
    public bool IsAnyCharPushed;

    public MultiLineCommentState()
    { }

    public MultiLineCommentState(MultiLineCommentState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsAnyCharPushed = prototype.IsAnyCharPushed;
    }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == '/' && Engine.previousChar == '*' && IsAnyCharPushed)
      {
        ExitState();
      }

      IsAnyCharPushed = true;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = ThisLineIndent.Clone();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new MultiLineCommentState(this, engine);
    }
  }

  #endregion

  #region StringLiteral state

  /// <summary>
  ///     StringLiteral state.
  /// </summary>
  public class StringLiteralState : IndentState
  {
    /// <summary>
    ///     True if the next char is escaped with '\'.
    /// </summary>
    public bool IsEscaped;

    public StringLiteralState()
    { }

    public StringLiteralState(StringLiteralState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsEscaped = prototype.IsEscaped;
    }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == Engine.newLineChar || (!IsEscaped && ch == '"')) {
        ExitState();
      } else {
        IsEscaped = ch == '\\' && !IsEscaped;
      }
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = Parent.NextLineIndent.Clone();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new StringLiteralState(this, engine);
    }
  }

  #endregion

  #region Verbatim string state

  /// <summary>
  ///     Verbatim string state.
  /// </summary>
  public class VerbatimStringState : IndentState
  {
    /// <summary>
    ///     True if there is an odd number of '"' in a row.
    /// </summary>
    public bool IsEscaped;

    public VerbatimStringState()
    { }

    public VerbatimStringState(VerbatimStringState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsEscaped = prototype.IsEscaped;
    }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (IsEscaped && ch != '"')
      {
        ExitState();
        // the char has been pushed to the wrong state, push it back
        Engine.currentState.Push(ch);
      }

      IsEscaped = ch == '"' && !IsEscaped;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = new Indent(Engine.textEditorOptions);
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new VerbatimStringState(this, engine);
    }
  }

  #endregion

  #region Character state

  /// <summary>
  ///     Character state.
  /// </summary>
  public class CharacterState : IndentState
  {
    /// <summary>
    ///     True if the next char is escaped with '\'.
    /// </summary>
    public bool IsEscaped;

    public CharacterState()
    { }

    public CharacterState(CharacterState prototype, CSharpIndentEngine engine)
      : base(prototype, engine)
    {
      IsEscaped = prototype.IsEscaped;
    }

    public override void Push(char ch)
    {
      base.Push(ch);

      if (ch == Engine.newLineChar)
      {
        ExitState();
      }
      else if (!IsEscaped && ch == '\'')
      {
        ExitState();
      }

      IsEscaped = ch == '\\' && !IsEscaped;
    }

    public override void InitializeState()
    {
      ThisLineIndent = Parent.ThisLineIndent.Clone();
      NextLineIndent = Parent.NextLineIndent.Clone();
    }

    public override IndentState Clone(CSharpIndentEngine engine)
    {
      return new CharacterState(this, engine);
    }
  }

  #endregion
}