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# Package Gtk.Text`_`Iter

A Gtk_Text_Iter represents a location in the text. It becomes invalid if the characters/pixmaps/widgets (indexable objects) in the text buffer are changed.

- Gtk.Text_Iter Types
- Gtk.Text_Iter Subprograms

## Types

    type Gtk_Text_Iter is limited private;

    type Gtk_Text_Iter_Access is access all Gtk_Text_Iter;

## Subprograms

    procedure Copy
      (Source             :        Gtk_Text_Iter;
       Dest               : out    Gtk_Text_Iter);

| Create a copy of Source.

### Convert to different kinds of index

    function Get_Offset
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the character offset of an iterator. Each character in a Gtk_Text_Buffer has an offset, starting with 0 for the first character in the buffer. Use Gtk.Text_Buffer.Get_Iter_At_Offset to convert an offset back into an iterator.

    function Get_Line
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the line number containing the iterator. Lines in a Gtk_Text_Buffer are numbered beginning with 0 for the first line in the buffer.

    function Get_Line_Offset
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the character offset of the iterator, counting from the start of a newline-terminated line. The first character on the line has offset 0.

    function Get_Line_Index
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the byte index of the iterator, counting from the start of a newline-terminated line. Remember that Gtk_Text_Buffer encodes text in UTF-8, and that characters can require a variable number of bytes to represent.

    function Get_Visible_Line_Offset
      (Iter               :        Gtk_Text_Iter)
       return Gint;

    function Get_Visible_Line_Index
      (Iter               :        Gtk_Text_Iter)
       return Gint;

### Dereference operators

    function Get_Char
      (Iter               :        Gtk_Text_Iter)
       return Gunichar;

| Return the character immediately following Iter. If Iter is at the end of the buffer, then return ASCII.NUL.

    function Get_Char
      (Iter               :        Gtk_Text_Iter)
       return Character;

| Return the character immediately following Iter. If Iter is at the end of the buffer, then return ASCII.NUL. Note that this function assumes that the text is encoded in ASCII format. If this is not the case, use the Get_Char function that returns a Gunichar instead.

    function Get_Slice
      (Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return UTF8_String;

Return the text in the given range.
A "slice" is an array of characters encoded in UTF-8 format, including the Unicode "unknown" character 16#FFFC# for iterable non-character elements in the buffer, such as images. Because images are encoded in the slice, byte and character offsets in the returned array will correspond to byte offsets in the text buffer. Note that 16#FFFC# can occur in normal text as well, so it is not a reliable indicator that a pixbuf or widget is in the buffer.

    function Get_Slice
      (Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return Interfaces.C.Strings.chars_ptr;

| Same as above, but returns the row C string. The caller is responsible for freeing the string returned.

    function Get_Text
      (Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return UTF8_String;

| Return text in the given range. If the range contains non-text elements such as images, the character and byte offsets in the returned string will not correspond to character and byte offsets in the buffer. If you want offsets to correspond, see Get_Slice.

    function Get_Visible_Slice
      (Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return UTF8_String;

| Like Get_Slice, but invisible text is not included. Invisible text is usually invisible because a Gtk_Text_Tag with the "invisible" attribute turned on has been applied to it.

    function Get_Visible_Text
      (Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return UTF8_String;

| Like Get_Text, but invisible text is not included. Invisible text is usually invisible because a Gtk_Text_Tag with the "invisible" attribute turned on has been applied to it.

    function Get_Pixbuf
      (Iter               :        Gtk_Text_Iter)
       return Gdk.Pixbuf.Gdk_Pixbuf;

| If the location pointed to by Iter contains a pixbuf, the pixbuf is returned (with no new reference count added). Otherwise, null is returned.

    function Get_Child_Anchor
      (Iter               :        Gtk_Text_Iter)
       return Gtk.Text_Child.Gtk_Text_Child_Anchor;

| If the location pointed to by Iter contains a child anchor, the anchor is returned (with no new reference count added). Otherwise, null is returned.

    function Begins_Tag
      (Iter               :        Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null)
       return Boolean;

| Return True if Tag is toggled on at exactly this point. If Tag is null, return True if any tag is toggled on at this point. Return True if Iter is the start of the tagged range; Has_Tag tells you whether an iterator is within a tagged range.

    function Ends_Tag
      (Iter               :        Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null)
       return Boolean;

| Return True if Tag is toggled off at exactly this point. If Tag is null, return True if any tag is toggled off at this point. Note that the Ends_Tag return True if Iter is the end of the tagged range; Has_Tag tells you whether an iterator is within a tagged range.

    function Toggles_Tag
      (Iter               :        Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null)
       return Boolean;

| Whether a range with Tag applied to it begins or ends at Iter. Equivalent to "Begins_Tag (Iter, Tag) or else Ends_Tag (Iter, Tag)".

    function Has_Tag
      (Iter               :        Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null)
       return Boolean;

| Return True if Iter is within a range tagged with Tag.

    function Editable
      (Iter               :        Gtk_Text_Iter;
       Default_Setting    :        Boolean := True)
       return Boolean;

| Return whether Iter is within an editable region of text. Non-editable text is "locked" and can't be changed by the user via Gtk_Text_View. This function is simply a convenience wrapper around Get_Attributes. If no tags applied to this text affect editability, Default_Setting will be returned.

    function Can_Insert
      (Iter               :        Gtk_Text_Iter;
       Default_Editability  :        Boolean)
       return Boolean;

Return whether text inserted at Iter would be editable.
Considering the default editability of the buffer, and tags that affect editability, determines whether text inserted at Iter would be editable. If text inserted at Iter would be editable then the user should be allowed to insert text at Iter. Gtk.Text_Buffer.Insert_Interactive uses this function to decide whether insertions are allowed at a given position.

    function Starts_Word
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter begins a natural-language word. Word breaks are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango word break algorithms.

    function Ends_Word
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter ends a natural-language word. Word breaks are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango word break algorithms).

    function Inside_Word
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter is inside a natural-language word (as opposed to say inside some whitespace). Word breaks are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango word break algorithms).

    function Starts_Sentence
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter begins a sentence. Sentence boundaries are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango text boundary algorithms).

    function Ends_Sentence
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter ends a sentence. Sentence boundaries are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango text boundary algorithms).

    function Inside_Sentence
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Determine whether Iter is inside a sentence (as opposed to in between two sentences, e.g. after a period and before the first letter of the next sentence). Sentence boundaries are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango text boundary algorithms).

    function Starts_Line
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Return True if Iter begins a paragraph. i.e. if Get_Line_Offset would return 0. However this function is potentially more efficient than Get_Line_Offset because it doesn't have to compute the offset, it just has to see whether it's 0.

    function Ends_Line
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Return True if Iter points to the start of the paragraph delimiter characters for a line (delimiters will be either a newline, a carriage return, a carriage return followed by a newline, or a Unicode paragraph separator character). Note that an iterator pointing to the ASCII.LF of a ASCII.CR & ASCII.LF pair will not be counted as the end of a line, the line ends before the ASCII.CR.

    function Is_Cursor_Position
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Return True if the cursor can be placed at Iter. See Forward_Cursor_Position for details on what a cursor position is.

    function Get_Chars_In_Line
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the number of characters in the line containing Iter, including the paragraph delimiters.

    function Get_Bytes_In_Line
      (Iter               :        Gtk_Text_Iter)
       return Gint;

| Return the number of bytes in the line containing Iter, including the paragraph delimiters.

    function Get_Language
      (Iter               :        Gtk_Text_Iter)
       return UTF8_String;

| A convenience wrapper around Get_Attributes, which returns the language in effect at Iter. If no tags affecting language apply to Iter, the return value is identical to that of Gtk.Get_Default_Language.

    function Is_End
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Return True if Iter is the end iterator. i.e. one past the last dereferenceable iterator in the buffer. This is the most efficient way to check whether an iterator is the end iterator.

    function Is_Start
      (Iter               :        Gtk_Text_Iter)
       return Boolean;

| Return True if Iter is the first iterator in the buffer, that is if Iter has a character offset of 0.

### Moving around the buffer

    procedure Forward_Char
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move Iter forward by one character offset. Note that images embedded in the buffer occupy 1 character slot, so Forward_Char may actually move onto an image instead of a character, if you have images in your buffer. If Iter is the end iterator or one character before it, Iter will now point at the end iterator, and Forward_Char returns False for convenience when writing loops.

    procedure Backward_Char
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move backward by one character offset. Return True if movement was possible; if Iter was the first in the buffer (character offset 0), return False for convenience when writing loops.

    procedure Forward_Chars
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Move Count characters if possible. If Count would move past the start or end of the buffer, move to the start or end of the buffer). Result indicates whether the new position of Iter is different from its original position, and dereferenceable (the last iterator in the buffer is not dereferenceable). If Count is 0, this procedure does nothing and returns False.

    procedure Backward_Chars
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Move Count characters backward, if possible. If Count would move past the start or end of the buffer, moves to the start or end of the buffer). Result indicates whether the iterator moved onto a dereferenceable position; if the iterator didn't move, or moved onto the end iterator, then False is returned. If Count is 0, the function does nothing and returns False.

    procedure Forward_Line
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move Iter to the start of the next line. Return True if there was a next line to move to, and False if iter was simply moved to the end of the buffer and is now not dereferenceable, or if Iter was already at the end of the buffer.

    procedure Backward_Line
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

Move Iter to the start of the previous line.
Return True if Iter could be moved; i.e. if Iter was at character offset 0, this function returns False. Therefore if Iter was already on line 0, but not at the start of the line, Iter is snapped to the start of the line and the function returns True. (Note that this implies that in a loop calling this function, the line number may not change on every iteration, if your first iteration is on line 0.)

    procedure Forward_Lines
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Forward_Line, up to Count times.

    procedure Backward_Lines
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Backward_Line, up to Count times.

    procedure Forward_Word_End
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move forward to the next word end. If Iter is currently on a word end, move forward to the next one after that. Word breaks are determined by Pango and should be correct for nearly any language (if not, the correct fix would be to the Pango word break algorithms).

    procedure Backward_Word_Start
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move backward to the next word start. If Iter is currently on a word start, move backward to the next one after that.

    procedure Forward_Word_Ends
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Forward_Word_End up to Count times.

    procedure Backward_Word_Starts
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Backward_Word_Start up to Count times.

    procedure Forward_Sentence_End
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move forward to the next sentence end. If Iter is at the end of a sentence, move to the next end of sentence.

    procedure Backward_Sentence_Start
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move backward to the next sentence start. If Iter is already at the start of a sentence, move backward to the next one.

    procedure Forward_Sentence_Ends
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Forward_Sentence_End up to Count times.

    procedure Backward_Sentence_Starts
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Backward_Sentence_Starts up to Count times.

    procedure Forward_Cursor_Position
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

Move Iter forward by a single cursor position.
Cursor positions are (unsurprisingly) positions where the cursor can appear. Perhaps surprisingly, there may not be a cursor position between all characters. The most common example for European languages would be a carriage return/newline sequence. For some Unicode characters, the equivalent of say the letter "a" with an accent mark will be represented as two characters, first the letter then a "combining mark" that causes the accent to be rendered; so the cursor can't go between those two characters.

    procedure Backward_Cursor_Position
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Like Forward_Cursor_Position, but moves backward.

    procedure Forward_Cursor_Positions
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Forward_Cursor_Position up to Count times.

    procedure Backward_Cursor_Positions
      (Iter               : in out Gtk_Text_Iter;
       Count              :        Gint := 1;
       Result             : out    Boolean);

| Call Backward_Cursor_Position up to Count times.

    procedure Set_Offset
      (Iter               : in out Gtk_Text_Iter;
       Char_Offset        :        Gint);

| Set Iter to point to Char_Offset. Char_Offset counts from the start of the entire text buffer, starting with 0.

    procedure Set_Line
      (Iter               : in out Gtk_Text_Iter;
       Line_Number        :        Gint);

| Move iterator Iter to the start of the line Line_Number.

    procedure Set_Line_Offset
      (Iter               : in out Gtk_Text_Iter;
       Char_On_Line       :        Gint);

| Move Iter within a line, to a new character (not byte) offset. The given character offset must be less than or equal to the number of characters in the line; if equal, Iter moves to the start of the next line. See Set_Line_Index if you have a byte index rather than a character offset.

    procedure Set_Line_Index
      (Iter               : in out Gtk_Text_Iter;
       Byte_On_Line       :        Gint);

| Same as Set_Line_Offset, but work with a byte index. The given byte index must be at the start of a character, it can't be in the middle of a UTF-8 encoded character.

    procedure Forward_To_End
      (Iter               : in out Gtk_Text_Iter);

| Move Iter forward to the "end iterator", which points one past the last valid character in the buffer. Get_Char called on the end iterator returns 0, which is convenient for writing loops.

    procedure Forward_To_Line_End
      (Iter               : in out Gtk_Text_Iter;
       Result             : out    Boolean);

| Move the iterator to point to the paragraph delimiter characters, which will be either a newline, a carriage return, a carriage return/newline in sequence, or the Unicode paragraph separator character. If the iterator is already at the paragraph delimiter characters, move to the paragraph delimiter characters for the next line.

    procedure Set_Visible_Line_Offset
      (Iter               : in out Gtk_Text_Iter;
       Char_On_Line       :        Gint);

| Like Set_Line_Index, but the index is in visible bytes. I.e. text with a tag making it invisible is not counted in the index.

    procedure Set_Visible_Line_Index
      (Iter               : in out Gtk_Text_Iter;
       Byte_On_Line       :        Gint);

| Like Set_Line_Offset, but the offset is in visible characters. I.e. text with a tag making it invisible is not counted in the offset.

    procedure Forward_To_Tag_Toggle
      (Iter               : in out Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null;
       Result             : out    Boolean);

| Move forward to the next toggle (on or off) of the Gtk_Text_Tag Tag, or to the next toggle of any tag if Tag is null. If no matching tag toggles are found, return False, otherwise True. Do not return toggles located at Iter, only toggles after Iter. Set Iter to the location of the toggle, or to the end of the buffer if no toggle is found.

    procedure Backward_To_Tag_Toggle
      (Iter               : in out Gtk_Text_Iter;
       Tag                :        Gtk.Text_Tag.Gtk_Text_Tag
                           := null;
       Result             : out    Boolean);

| Move backward to the next toggle (on or off) of the Gtk_Text_Tag Tag, or to the next toggle of any tag if Tag is null. If no matching tag toggles are found, return False, otherwise True. Do not return toggles located at Iter, only toggles before Iter. Set Iter to the location of the toggle, or the start of the buffer if no toggle is found.

    procedure Forward_Search
      (Iter               :        Gtk_Text_Iter;
       Str                :        UTF8_String;
       Visible_Only       :        Boolean := False;
       Slice              :        Boolean;
       Match_Start        : out    Gtk_Text_Iter;
       Match_End          : out    Gtk_Text_Iter;
       Limit              :        Gtk_Text_Iter;
       Result             : out    Boolean);

Search forward for Str.
Any match is returned as the range Match_Start, Match_End. If you specify Visible_Only or Slice, the match may have invisible text, pixbufs, or child widgets interspersed in Str. Iter: start of search Str: a search string Visible_Only: if True, search only visible text Slice: if True, Str contains 16#FFFC# when we want to match widgets, pixbufs Match_Start: return location for start of match, or null Match_End: return location for end of match, or null Limit: bound for the search, or null for the end of the buffer Result: whether a match was found.

    procedure Backward_Search
      (Iter               :        Gtk_Text_Iter;
       Str                :        UTF8_String;
       Visible_Only       :        Boolean := False;
       Slice              :        Boolean;
       Match_Start        : out    Gtk_Text_Iter;
       Match_End          : out    Gtk_Text_Iter;
       Limit              :        Gtk_Text_Iter;
       Result             : out    Boolean);

| Same as Forward_Search, but move backward.

### Comparisons

    function Equal
      (Lhs                :        Gtk_Text_Iter;
       Rhs                :        Gtk_Text_Iter)
       return Boolean;

| Test whether two iterators are equal, using the fastest possible mechanism. This function is very fast; you can expect it to perform better than e.g. getting the character offset for each iterator and comparing the offsets yourself. Also, it's a bit faster than Compare.

    function Compare
      (Lhs                :        Gtk_Text_Iter;
       Rhs                :        Gtk_Text_Iter)
       return Gint;

| A quick sort-style function that return negative if Lhs is less than Rhs, positive if Lhs is greater than Rhs, and 0 if they're equal. Ordering is in character offset order, i.e. the first character in the buffer is less than the second character in the buffer.

    function In_Range
      (Iter               :        Gtk_Text_Iter;
       Start              :        Gtk_Text_Iter;
       The_End            :        Gtk_Text_Iter)
       return Boolean;

| Start and End must be in order, unlike most text buffer functions, for efficiency reasons. Return True if Iter falls in the range [Start, End)

    procedure Order
      (First              : in out Gtk_Text_Iter;
       Second             : in out Gtk_Text_Iter);

| Swap the value of First and Second if Second comes before First in the buffer. That is, ensures that First and Second are in sequence. Most text buffer functions that take a range call this automatically on your behalf, so there's no real reason to call it yourself in those cases. There are some exceptions, such as In_Range, that expect a pre-sorted range.

### Converting to/from GValue

    procedure Set_Text_Iter
      (Val                : in out Glib.Values.GValue;
       Iter               :        Gtk_Text_Iter);

| Set the value of the given GValue to Iter. Note that Iter is stored by reference, which means no copy of Iter is made. Iter should remain allocated as long as Val is being used.

    procedure Get_Text_Iter
      (Val                :        Glib.Values.GValue;
       Iter               : out    Gtk_Text_Iter);

| Extract the iterator from the given GValue. Note that the iterator returned is a copy of the iterator referenced by the give GValue. Modifying the iterator returned does not modify the iterator referenced by the GValue.

    function Get_Text_Iter
      (Val                :        Glib.Values.GValue)
       return Gtk_Text_Iter;

| This is the function equivalent of procedure Get_Text_Iter above. It is sometimes more convenient that then procedure, but its use is limited by the fact that the result returned can not be stored in a variable, since Gtk_Text_Iter is limited.

    function C_Gtk_Text_Iter_Size  return Gint;

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