path: root/starmath/inc/cursor.hxx

/*
 * Version: MPL 1.1 / GPLv3+ / LGPLv3+
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Initial Developer of the Original Code is
 *       Jonas Finnemann Jensen <jopsen@gmail.com>
 * Portions created by the Initial Developer are Copyright (C) 2010 the
 * Initial Developer. All Rights Reserved.
 *
 * Contributor(s): Jonas Finnemann Jensen <jopsen@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 3 or later (the "GPLv3+"), or
 * the GNU Lesser General Public License Version 3 or later (the "LGPLv3+"),
 * in which case the provisions of the GPLv3+ or the LGPLv3+ are applicable
 * instead of those above.
 */
#ifndef SMCURSOR_H
#define SMCURSOR_H

#include "node.hxx"
#include "caret.hxx"

/** Factor to multiple the squared horizontical distance with
 * Used for Up and Down movement.
 */
#define HORIZONTICAL_DISTANCE_FACTOR        10

/** Enum of direction for movement */
enum SmMovementDirection{
    MoveUp,
    MoveDown,
    MoveLeft,
    MoveRight
};

/** Enum of elements that can inserted into a formula */
enum SmFormulaElement{
    BlankElement,
    FactorialElement,
    PlusElement,
    MinusElement,
    CDotElement,
    EqualElement,
    LessThanElement,
    GreaterThanElement
};

/** Bracket types that can be inserted */
enum SmBracketType {
    /** None brackets, left command "none" */
    NoneBrackets,
    /** Round brackets, left command "(" */
    RoundBrackets,
    /**Square brackets, left command "[" */
    SquareBrackets,
    /** Double square brackets, left command "ldbracket" */
    DoubleSquareBrackets,
    /** Line brackets, left command "lline" */
    LineBrackets,
    /** Double line brackets, left command "ldline" */
    DoubleLineBrackets,
    /** Curly brackets, left command "lbrace" */
    CurlyBrackets,
    /** Angle brackets, left command "langle" */
    AngleBrackets,
    /** Ceiling brackets, left command "lceil" */
    CeilBrackets,
    /** Floor brackets, left command "lfloor" */
    FloorBrackets
};

/** A list of nodes */
typedef std::list<SmNode*> SmNodeList;

class SmDocShell;

/** Formula cursor
 *
 * This class is used to represent a cursor in a formula, which can be used to manipulate
 * an formula programmatically.
 * @remarks This class is a very intimite friend of SmDocShell.
 */
class SmCursor{
public:
    SmCursor(SmNode* tree, SmDocShell* pShell){
        //Initialize members
        pTree           = tree;
        anchor          = NULL;
        position        = NULL;
        pGraph          = NULL;
        pDocShell       = pShell;
        pClipboard      = NULL;
        nEditSections   = 0;
        //Build graph
        BuildGraph();
    }

    ~SmCursor(){
        SetClipboard();
        if(pGraph)
            delete pGraph;
        pGraph = NULL;
    }

    /** Gets the anchor */
    SmCaretPos GetAnchor(){ return anchor->CaretPos; }

    /** Get position */
    SmCaretPos GetPosition() { return position->CaretPos; }

    /** True, if the cursor has a selection */
    bool HasSelection() { return anchor != position; }

    /** Move the position of this cursor */
    void Move(OutputDevice* pDev, SmMovementDirection direction, bool bMoveAnchor = true);

    /** Move to the caret position closet to a given point */
    void MoveTo(OutputDevice* pDev, Point pos, bool bMoveAnchor = true);

    /** Delete the current selection or do nothing */
    void Delete();

    /** Insert text at the current position */
    void InsertText(XubString aString);

    /** Insert an element into the formula */
    void InsertElement(SmFormulaElement element);

    /** Insert a command specified in commands.src*/
    void InsertCommand(USHORT nCommand);

    /** Insert command text translated into line entries at position
     *
     * Note: This method uses the parser to translate a command text into a
     * tree, then it copies line entries from this tree into the current tree.
     * Will not work for commands such as newline or ##, if position is in a matrix.
     * This will work for stuff like "A intersection B". But stuff spaning multiple lines
     * or dependent on the context which position is placed in will not work!
     */
    void InsertCommandText(String aCommandText);

    /** Insert a special node created from aString
     *
     * Used for handling insert request from the "catalog" dialog.
     * The provided string should be formatet as the desired command: %phi
     * Note: this method ONLY supports commands defined in Math.xcu
     *
     * For more complex expressions use InsertCommandText, this method doesn't
     * use SmParser, this means that it's faster, but not as strong.
     */
    void InsertSpecial(XubString aString);

    /** Create sub-/super script
     *
     * If there's a selection, it will be move into the appropriate sub-/super scription
     * of the node infront of it. If there's no node infront of position (or the selection),
     * a sub-/super scription of a new SmPlaceNode will be made.
     *
     * If there's is an existing subscription of the node, the caret will be moved into it,
     * and any selection will replace it.
     */
    void InsertSubSup(SmSubSup eSubSup);

    /** Create a limit on an SmOperNode
     *
     * This this method only work if the caret is inside an SmOperNode, or to the right of one.
     * Notice also that this method ignores any selection made.
     *
     * @param bMoveCaret If true that caret will be moved into the limit.
     *
     * @returns True, if the caret was in a context where this operation was possible.
     */
    BOOL InsertLimit(SmSubSup eSubSup, BOOL bMoveCaret = TRUE);

    /** Insert a new row or newline
     *
     * Inserts a new row if position is in an matrix or stack command.
     * Otherwise a newline is inserted if we're in a toplevel line.
     *
     * @returns True, if a new row/line could be inserted.
     *
     * @remarks If the caret is placed in a subline of a command that doesn't support
     *          this operator the method returns FALSE, and doesn't do anything.
     */
    BOOL InsertRow();

    /** Insert a fraction, use selection as numerator */
    void InsertFraction();

    /** Create brackets around current selection, or new SmPlaceNode */
    void InsertBrackets(SmBracketType eBracketType);

    /** Copy the current selection */
    void Copy();
    /** Cut the current selection */
    void Cut(){
        Copy();
        Delete();
    }
    /** Paste the clipboard */
    void Paste();

    /** Returns true if more than one node is selected
     *
     * This method is used for implementing backspace and delete.
     * If one of these causes a complex selection, e.g. a node with
     * subnodes or similar, this should not be deleted imidiately.
     */
    bool HasComplexSelection();

    /** Finds the topmost node in a visual line
     *
     * If MoveUpIfSelected is true, this will move up to the parent line
     * if the parent of the current line is selected.
     */
    static SmNode* FindTopMostNodeInLine(SmNode* pSNode, bool MoveUpIfSelected = false);

    /** Draw the caret */
    void Draw(OutputDevice& pDev, Point Offset);

private:
    friend class SmDocShell;

    SmCaretPosGraphEntry    *anchor,
                            *position;
    /** Formula tree */
    SmNode* pTree;
    /** Owner of the formula tree */
    SmDocShell* pDocShell;
    /** Graph over caret position in the current tree */
    SmCaretPosGraph* pGraph;
    /** Clipboard holder */
    SmNodeList* pClipboard;

    /** Returns a node that is selected, if any could be found */
    SmNode* FindSelectedNode(SmNode* pNode);

    /** Is this one of the nodes used to compose a line
     *
     * These are SmExpression, SmBinHorNode, SmUnHorNode etc.
     */
    static bool IsLineCompositionNode(SmNode* pNode);

    /** Count number of selected nodes, excluding line composition nodes
     *
     * Note this function doesn't count line composition nodes and it
     * does count all subnodes as well as the owner nodes.
     *
     * Used by SmCursor::HasComplexSelection()
     */
    int CountSelectedNodes(SmNode* pNode);

    /** Convert a visual line to a list
     *
     * Note this method will delete all the nodes that will no longer be needed.
     * that includes pLine!
     * This method also deletes SmErrorNode's as they're just meta info in the line.
     */
    static SmNodeList* LineToList(SmStructureNode* pLine, SmNodeList* pList = new SmNodeList());

    /** Clone a visual line to a list
     *
     * Doesn't clone SmErrorNode's these are ignored, as they are context dependent metadata.
     */
    static SmNodeList* CloneLineToList(SmStructureNode* pLine,
                                       bool bOnlyIfSelected = false,
                                       SmNodeList* pList = new SmNodeList());

    /** Build pGraph over caret positions */
    void BuildGraph();

    /** Insert new nodes in the tree after position */
    void InsertNodes(SmNodeList* pNewNodes);

    /** tries to set position to a specific SmCaretPos
     *
     * @returns false on failure to find the position in pGraph.
     */
    bool SetCaretPosition(SmCaretPos pos, bool moveAnchor = false);

    /** Set selected on nodes of the tree */
    void AnnotateSelection();

    /** Set the clipboard, and release current clipboard
     *
     * Call this method with NULL to reset the clipboard
     * @remarks: This method takes ownership of pList.
     */
    void SetClipboard(SmNodeList* pList = NULL);

    /** Clone list of nodes (creates a deep clone) */
    static SmNodeList* CloneList(SmNodeList* pList);

    /** Find an iterator pointing to the node in pLineList following aCaretPos
     *
     * If aCaretPos::pSelectedNode cannot be found it is assumed that it's infront of pLineList,
     * thus not an element in pLineList. In this case this method returns an iterator to the
     * first element in pLineList.
     *
     * If the current position is inside an SmTextNode, this node will be split in two, for this
     * reason you should beaware that iterators to elements in pLineList may be invalidated, and
     * that you should call PatchLineList() with this iterator if no action is taken.
     */
    static SmNodeList::iterator FindPositionInLineList(SmNodeList* pLineList, SmCaretPos aCaretPos);

    /** Patch a line list after modification, merge SmTextNode, remove SmPlaceNode etc.
     *
     * @param pLineList The line list to patch
     * @param aIter     Iterator pointing to the element that needs to be patched with it's previous.
     *
     * When the list is patched text nodes before and after aIter will be merged.
     * If there's an, in the context, inappropriate SmPlaceNode before or after aIter it will also be
     * removed.
     *
     * @returns A caret position equivalent to one selecting the node before aIter, the method returns
     *          an invalid SmCaretPos to indicate placement infront of the line.
     */
     static SmCaretPos PatchLineList(SmNodeList* pLineList, SmNodeList::iterator aIter);

    /** Take selected nodes from a list
     *
     * Puts the selected nodes into pSelectedNodes, or if pSelectedNodes is NULL deletes
     * the selected nodes.
     * Note: If there's a selection inside an SmTextNode this node will be split, and it
     * will not be merged when the selection have been taken. Use PatchLineList on the
     * iterator returns to fix this.
     *
     * @returns An iterator pointing to the element following the selection taken.
     */
    static SmNodeList::iterator TakeSelectedNodesFromList(SmNodeList *pLineList,
                                                         SmNodeList *pSelectedNodes = NULL);

    /** Create an instance of SmMathSymbolNode usable for brackets */
    static SmNode *CreateBracket(SmBracketType eBracketType, BOOL bIsLeft);

    /** The number of times BeginEdit have been called
     * Used to allow nesting of BeginEdit() and EndEdit() sections
     */
    int nEditSections;
    /** Holds data for BeginEdit() and EndEdit() */
    BOOL bIsEnabledSetModifiedSmDocShell;
    /** Begin edit section where the tree will be modified */
    void BeginEdit();
    /** End edit section where the tree will be modified */
    void EndEdit();
    /** Finish editing
     *
     * Finishes editing by parsing pLineList and inserting back into pParent at nParentIndex.
     * This method also rebuilts the graph, annotates the selection, sets caret position and
     * Calls EndEdit.
     *
     * @remarks Please note that this method will delete pLineList, as the elements are taken.
     *
     * @param pLineList     List the constitutes the edited line.
     * @param pParent       Parent to which the line should be inserted.
     * @param nParentIndex  Index in parent where the line should be inserted.
     * @param PosAfterEdit  Caret position to look for after rebuilding graph.
     * @param pStartLine    Line to take first position in, if PosAfterEdit cannot be found,
     *                      leave it NULL for pLineList.
     */
    void FinishEdit(SmNodeList* pLineList,
                    SmStructureNode* pParent,
                    int nParentIndex,
                    SmCaretPos PosAfterEdit,
                    SmNode* pStartLine = NULL);
    /** Request the formula is repainted */
    void RequestRepaint();
};

/** Minimalistic recursive decent SmNodeList parser
 *
 * This parser is used to take a list of nodes that constitues a line
 * and parse them to a tree of SmBinHorNode, SmUnHorNode and SmExpression.
 *
 * Please note, this will not handle all kinds of nodes, only nodes that
 * constitues and entry in a line.
 *
 * Below is an EBNF representation of the grammar used for this parser:
 * \code
 * Expression   -> Relation*
 * Relation     -> Sum [(=|<|>|...) Sum]*
 * Sum          -> Product [(+|-) Product]*
 * Product      -> Factor [(*|/) Factor]*
 * Factor       -> [+|-|-+|...]* Factor | Postfix
 * Postfix      -> node [!]*
 * \endcode
 */
class SmNodeListParser{
public:
    /** Create an instance of SmNodeListParser */
    SmNodeListParser(){
        pList = NULL;
    }
    /** Parse a list of nodes to an expression
     *
     * If bDeleteErrorNodes is true, old error nodes will be deleted.
     */
    SmNode* Parse(SmNodeList* list, bool bDeleteErrorNodes = true);
    /** True, if the token is an operator */
    static BOOL IsOperator(const SmToken &token);
    /** True, if the token is a relation operator */
    static BOOL IsRelationOperator(const SmToken &token);
    /** True, if the token is a sum operator */
    static BOOL IsSumOperator(const SmToken &token);
    /** True, if the token is a product operator */
    static BOOL IsProductOperator(const SmToken &token);
    /** True, if the token is a unary operator */
    static BOOL IsUnaryOperator(const SmToken &token);
    /** True, if the token is a postfix operator */
    static BOOL IsPostfixOperator(const SmToken &token);
private:
    SmNodeList* pList;
    /** Get the current terminal */
    SmNode* Terminal(){
        if(pList->size() > 0)
            return pList->front();
        return NULL;
    }
    /** Move to next terminal */
    SmNode* Next(){
        pList->pop_front();
        return Terminal();
    }
    /** Take the current terminal */
    SmNode* Take(){
        SmNode* pRetVal = Terminal();
        Next();
        return pRetVal;
    }
    SmNode* Expression();
    SmNode* Relation();
    SmNode* Sum();
    SmNode* Product();
    SmNode* Factor();
    SmNode* Postfix();
    SmNode* Error();
};


#endif /* SMCURSOR_H */