Implement semantic and line selection dragging

Unlike the regular selection that is by cell, these selection modes
highlight either semantic groupings or entire lines while the mouse is
dragged.

7 files changed, 373 insertions, 217 deletions

diff --git a/src/display.rs b/src/display.rs
index d8c10d18..00427e34 100644
--- a/src/display.rs
+++ b/src/display.rs
@@ -277,7 +277,7 @@ impl Display {
     /// A reference to Term whose state is being drawn must be provided.
     ///
     /// This call may block if vsync is enabled
-    pub fn draw(&mut self, mut terminal: MutexGuard<Term>, config: &Config, selection: &Selection) {
+    pub fn draw(&mut self, mut terminal: MutexGuard<Term>, config: &Config, selection: Option<&Selection>) {
         // Clear dirty flag
         terminal.dirty = !terminal.visual_bell.completed();
 
diff --git a/src/event.rs b/src/event.rs
index 2d50234d..abbad0ef 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -33,7 +33,7 @@ pub trait Notify {
 pub struct ActionContext<'a, N: 'a> {
     pub notifier: &'a mut N,
     pub terminal: &'a mut Term,
-    pub selection: &'a mut Selection,
+    pub selection: &'a mut Option<Selection>,
     pub size_info: &'a SizeInfo,
     pub mouse: &'a mut Mouse,
 }
@@ -52,32 +52,46 @@ impl<'a, N: Notify + 'a> input::ActionContext for ActionContext<'a, N> {
     }
 
     fn copy_selection(&self, buffer: ::copypasta::Buffer) {
-        if let Some(selection) = self.selection.span() {
-            let buf = self.terminal.string_from_selection(&selection);
-            if !buf.is_empty() {
-                Clipboard::new()
-                    .and_then(|mut clipboard| clipboard.store(buf, buffer))
-                    .unwrap_or_else(|err| {
-                        warn!("Error storing selection to clipboard. {}", Red(err));
-                    });
-            }
+        if let &mut Some(ref selection) = self.selection {
+            selection.to_span(self.terminal as &Term)
+                .map(|span| {
+                    let buf = self.terminal.string_from_selection(&span);
+                    if !buf.is_empty() {
+                        Clipboard::new()
+                            .and_then(|mut clipboard| clipboard.store(buf, buffer))
+                            .unwrap_or_else(|err| {
+                                warn!("Error storing selection to clipboard. {}", Red(err));
+                            });
+                    }
+                });
         }
     }
 
     fn clear_selection(&mut self) {
-        self.selection.clear();
+        *self.selection = None;
     }
 
     fn update_selection(&mut self, point: Point, side: Side) {
-        self.selection.update(point, side);
+        // Update selection if one exists
+        if let &mut Some(ref mut selection) = self.selection {
+            selection.update(point, side);
+            return;
+        }
+
+        // Otherwise, start a regular selection
+        self.simple_selection(point, side);
+    }
+
+    fn simple_selection(&mut self, point: Point, side: Side) {
+        *self.selection = Some(Selection::simple(point, side));
     }
 
     fn semantic_selection(&mut self, point: Point) {
-        self.terminal.semantic_selection(&mut self.selection, point)
+        *self.selection = Some(Selection::semantic(point, self.terminal as &Term));
     }
 
     fn line_selection(&mut self, point: Point) {
-        self.terminal.line_selection(&mut self.selection, point)
+        *self.selection = Some(Selection::lines(point));
     }
 
     fn mouse_coords(&self) -> Option<Point> {
@@ -141,7 +155,7 @@ pub struct Processor<N> {
     resize_tx: mpsc::Sender<(u32, u32)>,
     ref_test: bool,
     size_info: SizeInfo,
-    pub selection: Selection,
+    pub selection: Option<Selection>,
     hide_cursor_when_typing: bool,
     hide_cursor: bool,
 }
@@ -178,7 +192,7 @@ impl<N: Notify> Processor<N> {
             resize_tx: resize_tx,
             ref_test: ref_test,
             mouse: Default::default(),
-            selection: Default::default(),
+            selection: None,
             size_info: size_info,
             hide_cursor_when_typing: config.hide_cursor_when_typing(),
             hide_cursor: false,
@@ -243,7 +257,13 @@ impl<N: Notify> Processor<N> {
                 *hide_cursor = false;
                 processor.mouse_moved(x as u32, y as u32);
 
-                if !processor.ctx.selection.is_empty() {
+                if !processor.ctx.selection.is_none() {
+                    // TODO this should only be passed if the selection changes
+                    // which happens when the point/side change *and* the mouse
+                    // is still pressed.
+                    //
+                    // Right now, this causes lots of unnecessary redraws while
+                    // selection is active.
                     processor.ctx.terminal.dirty = true;
                 }
             },
diff --git a/src/grid.rs b/src/grid.rs
index cdb93c96..f630045a 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -30,7 +30,7 @@ use index::{self, Point, Line, Column, IndexRange, RangeInclusive};
 
 /// Convert a type to a linear index range.
 pub trait ToRange {
-    fn to_range(&self, columns: index::Column) -> RangeInclusive<index::Linear>;
+    fn to_range(&self) -> RangeInclusive<index::Linear>;
 }
 
 /// Bidirection iterator
diff --git a/src/input.rs b/src/input.rs
index de8bca45..920e55f5 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -54,9 +54,10 @@ pub trait ActionContext {
     fn size_info(&self) -> SizeInfo;
     fn copy_selection(&self, Buffer);
     fn clear_selection(&mut self);
-    fn update_selection(&mut self, Point, Side);
-    fn semantic_selection(&mut self, Point);
-    fn line_selection(&mut self, Point);
+    fn update_selection(&mut self, point: Point, side: Side);
+    fn simple_selection(&mut self, point: Point, side: Side);
+    fn semantic_selection(&mut self, point: Point);
+    fn line_selection(&mut self, point: Point);
     fn mouse_mut(&mut self) -> &mut Mouse;
     fn mouse_coords(&self) -> Option<Point>;
 }
@@ -494,7 +495,6 @@ mod tests {
     use term::{SizeInfo, Term, TermMode, mode};
     use event::{Mouse, ClickState};
     use config::{self, Config, ClickHandler};
-    use selection::Selection;
     use index::{Point, Side};
 
     use super::{Action, Binding, Processor};
@@ -510,7 +510,7 @@ mod tests {
 
     struct ActionContext<'a> {
         pub terminal: &'a mut Term,
-        pub selection: &'a mut Selection,
+        pub selection: Option<&'a mut Selection>,
         pub size_info: &'a SizeInfo,
         pub mouse: &'a mut Mouse,
         pub last_action: MultiClick,
@@ -578,15 +578,16 @@ mod tests {
                     padding_y: 0.0,
                 };
 
+                use ::ansi::TermInfo;
+
                 let mut terminal = Term::new(&config, size);
 
                 let mut mouse = Mouse::default();
-                let mut selection = Selection::new();
                 mouse.click_state = $initial_state;
 
                 let context = ActionContext {
                     terminal: &mut terminal,
-                    selection: &mut selection,
+                    selection: None,
                     mouse: &mut mouse,
                     size_info: &size,
                     last_action: MultiClick::None,
diff --git a/src/main.rs b/src/main.rs
index f4ee72b6..9db5ce58 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -179,7 +179,7 @@ fn run(mut config: Config, options: cli::Options) -> Result<(), Box<Error>> {
             display.handle_resize(&mut terminal, &mut [&mut pty, &mut processor]);
 
             // Draw the current state of the terminal
-            display.draw(terminal, &config, &processor.selection);
+            display.draw(terminal, &config, processor.selection.as_ref());
         }
 
         // Begin shutdown if the flag was raised.
diff --git a/src/selection.rs b/src/selection.rs
index 3e5b799c..868ded7b 100644
--- a/src/selection.rs
+++ b/src/selection.rs
@@ -19,141 +19,285 @@
 //! when text is added/removed/scrolled on the screen. The selection should
 //! also be cleared if the user clicks off of the selection.
 use std::mem;
+use std::cmp::min;
+use std::cmp::max;
 
 use index::{Point, Column, RangeInclusive, Side, Linear, Line};
-use grid::ToRange;
+use grid::{Grid, ToRange};
+use term::Cell;
 
-/// The area selected
+/// Describes a region of a 2-dimensional area
 ///
-/// Contains all the logic for processing mouse position events and providing
-/// necessary info the the renderer.
-#[derive(Debug)]
+/// Used to track a text selection. There are three supported modes, each with its own constructor:
+/// [`simple`], [`semantic`], and [`lines`]. The [`simple`] mode precisely tracks which cells are
+/// selected without any expansion. [`semantic`] mode expands the initial selection to the nearest
+/// semantic escape char in either direction. [`lines`] will always select entire lines.
+///
+/// Calls to [`update`] operate different based on the selection kind. The [`simple`] mode does
+/// nothing special, simply tracks points and sides. [`semantic`] will continue to expand out to
+/// semantic boundaries as the selection point changes. Similarly, [`lines`] will always expand the
+/// new point to encompass entire lines.
+///
+/// [`simple`]: enum.Selection.html#method.simple
+/// [`semantic`]: enum.Selection.html#method.semantic
+/// [`lines`]: enum.Selection.html#method.lines
 pub enum Selection {
-    /// No current selection or start of a selection
-    Empty,
-
-    Active {
-        start: Point,
-        end: Point,
-        start_side: Side,
-        end_side: Side
+    Simple {
+        /// The region representing start and end of cursor movement
+        region: Region<Anchor>,
     },
+    Semantic {
+        /// The region representing start and end of cursor movement
+        region: Region<Point>,
+
+        /// When begining a semantic selection, the grid is searched around the
+        /// initial point to find semantic escapes, and this initial expansion
+        /// marks those points.
+        initial_expansion: Region<Point>
+    },
+    Lines {
+        /// The region representing start and end of cursor movement
+        region: Region<Point>,
+
+        /// The line under the initial point. This is always selected regardless
+        /// of which way the cursor is moved.
+        initial_line: Line
+    }
+}
+
+pub struct Region<T> {
+    start: T,
+    end: T
+}
+
+/// A Point and side within that point.
+pub struct Anchor {
+    point: Point,
+    side: Side,
 }
 
-impl Default for Selection {
-    fn default() -> Selection {
-        Selection::Empty
+impl Anchor {
+    fn new(point: Point, side: Side) -> Anchor {
+        Anchor { point: point, side: side }
     }
 }
 
+/// A type that can expand a given point to a region
+///
+/// Usually this is implemented for some 2-D array type since
+/// points are two dimensional indices.
+pub trait SemanticSearch {
+    /// Find the nearest semantic boundary _to the left_ of provided point.
+    fn semantic_search_left(&self, _: Point) -> Point;
+    /// Find the nearest semantic boundary _to the point_ of provided point.
+    fn semantic_search_right(&self, _: Point) -> Point;
+}
+
+/// A type that has 2-dimensional boundaries
+pub trait Dimensions {
+    /// Get the size of the area
+    fn dimensions(&self) -> Point;
+}
+
 impl Selection {
-    /// Create a selection in the default state
-    #[inline]
-    pub fn new() -> Selection {
-        Default::default()
+    pub fn simple(location: Point, side: Side) -> Selection {
+        Selection::Simple {
+            region: Region {
+                start: Anchor::new(location, side),
+                end: Anchor::new(location, side)
+            }
+        }
     }
 
-    /// Clear the active selection
-    pub fn clear(&mut self) {
-        mem::replace(self, Selection::Empty);
+    pub fn semantic<G: SemanticSearch>(point: Point, grid: G) -> Selection {
+        let (start, end) = (grid.semantic_search_left(point), grid.semantic_search_right(point));
+        Selection::Semantic {
+            region: Region {
+                start: point,
+                end: point,
+            },
+            initial_expansion: Region {
+                start: start,
+                end: end
+            }
+        }
     }
 
-    pub fn is_empty(&self) -> bool {
-        match *self {
-            Selection::Empty => true,
-            _ => false
+    pub fn lines(point: Point) -> Selection {
+        Selection::Lines {
+            region: Region {
+                start: point,
+                end: point
+            },
+            initial_line: point.line
         }
     }
 
     pub fn update(&mut self, location: Point, side: Side) {
-        let selection = mem::replace(self, Selection::Empty);
-        let selection = match selection {
-            Selection::Empty => {
-                // Start a selection
-                Selection::Active {
-                    start: location,
-                    end: location,
-                    start_side: side,
-                    end_side: side
-                }
+        // Always update the `end`; can normalize later during span generation.
+        match *self {
+            Selection::Simple { ref mut region } => {
+                region.end = Anchor::new(location, side);
+            },
+            Selection::Semantic { ref mut region, .. } => {
+                region.end = location;
             },
-            Selection::Active { start, start_side, .. } => {
-                // Update ends
-                Selection::Active {
-                    start: start,
-                    start_side: start_side,
-                    end: location,
-                    end_side: side
-                }
+            Selection::Lines { ref mut region, .. } => {
+                region.end = location;
             }
-        };
-
-        mem::replace(self, selection);
+        }
     }
 
-    pub fn span(&self) -> Option<Span> {
+    pub fn to_span<G: SemanticSearch + Dimensions>(&self, grid: G) -> Option<Span> {
         match *self {
-            Selection::Active { ref start, ref end, ref start_side, ref end_side } => {
-                let (front, tail, front_side, tail_side) = if *start > *end {
-                    // Selected upward; start/end are swapped
-                    (end, start, end_side, start_side)
-                } else {
-                    // Selected downward; no swapping
-                    (start, end, start_side, end_side)
-                };
-
-                debug_assert!(!(tail < front));
-
-                // Single-cell selections are a special case
-                if start == end {
-                    if start_side == end_side {
-                        return None;
-                    } else {
-                        return Some(Span {
-                            ty: SpanType::Inclusive,
-                            front: *front,
-                            tail: *tail
-                        });
-                    }
-                }
-
-                // The other special case is two adjacent cells with no
-                // selection: [ B][E ] or [ E][B ]
-                let adjacent = tail.line == front.line && tail.col - front.col == Column(1);
-                if adjacent && *front_side == Side::Right && *tail_side == Side::Left {
-                    return None;
-                }
-
-                Some(match (*front_side, *tail_side) {
-                    // [FX][XX][XT]
-                    (Side::Left, Side::Right) => Span {
-                        front: *front,
-                        tail: *tail,
-                        ty: SpanType::Inclusive
-                    },
-                    // [ F][XX][T ]
-                    (Side::Right, Side::Left) => Span {
-                        front: *front,
-                        tail: *tail,
-                        ty: SpanType::Exclusive
-                    },
-                    // [FX][XX][T ]
-                    (Side::Left, Side::Left) => Span {
-                        front: *front,
-                        tail: *tail,
-                        ty: SpanType::ExcludeTail
-                    },
-                    // [ F][XX][XT]
-                    (Side::Right, Side::Right) => Span {
-                        front: *front,
-                        tail: *tail,
-                        ty: SpanType::ExcludeFront
-                    },
-                })
+            Selection::Simple { ref region } => {
+                Selection::span_simple(grid, region)
+            },
+            Selection::Semantic { ref region, ref initial_expansion } => {
+                Selection::span_semantic(grid, region, initial_expansion)
             },
-            Selection::Empty => None
+            Selection::Lines { ref region, ref initial_line } => {
+                Selection::span_lines(grid, region, initial_line)
+            }
         }
     }
+    fn span_semantic<G>(
+        grid: G,
+        region: &Region<Point>,
+        initial_expansion: &Region<Point>
+    ) -> Option<Span>
+        where G: SemanticSearch + Dimensions
+    {
+        let mut start = initial_expansion.start;
+        let mut end = initial_expansion.end;
+
+        // Normalize ordering of selected cells
+        let (front, tail) = if region.start < region.end {
+            (region.start, region.end)
+        } else {
+            (region.end, region.start)
+        };
+
+        // Update start of selection *if* front has moved beyond initial start
+        if front < start {
+            start = grid.semantic_search_left(front);
+        }
+
+        // Update end of selection *if* tail has moved beyond initial end.
+        if tail > end {
+            end = grid.semantic_search_right(tail);
+        }
+
+        Some(Span {
+            cols: grid.dimensions().col,
+            front: start,
+            tail: end,
+            ty: SpanType::Inclusive,
+        })
+    }
+
+    fn span_lines<G>( grid: G, region: &Region<Point>, initial_line: &Line) -> Option<Span>
+        where G: Dimensions
+    {
+        // First, create start and end points based on initial line and the grid
+        // dimensions.
+        let mut start = Point {
+            col: Column(0),
+            line: *initial_line
+        };
+        let mut end = Point {
+            col: grid.dimensions().col - 1,
+            line: *initial_line
+        };
+
+        // Now, expand lines based on where cursor started and ended.
+        if region.start.line < region.end.line {
+            // Start is above end
+            start.line = min(start.line, region.start.line);
+            end.line = max(end.line, region.end.line);
+        } else {
+            // Start is below end
+            start.line = min(start.line, region.end.line);
+            end.line = max(end.line, region.start.line);
+        }
+
+        Some(Span {
+            cols: grid.dimensions().col,
+            front: start,
+            tail: end,
+            ty: SpanType::Inclusive
+        })
+    }
+
+    fn span_simple<G: Dimensions>(grid: G, region: &Region<Anchor>) -> Option<Span> {
+        let start = region.start.point;
+        let start_side = region.start.side;
+        let end = region.end.point;
+        let end_side = region.end.side;
+        let cols = grid.dimensions().col;
+
+        let (front, tail, front_side, tail_side) = if start > end {
+            // Selected upward; start/end are swapped
+            (end, start, end_side, start_side)
+        } else {
+            // Selected downward; no swapping
+            (start, end, start_side, end_side)
+        };
+
+        debug_assert!(!(tail < front));
+
+        // Single-cell selections are a special case
+        if start == end {
+            if start_side == end_side {
+                return None;
+            } else {
+                return Some(Span {
+                    cols: cols,
+                    ty: SpanType::Inclusive,
+                    front: front,
+                    tail: tail
+                });
+            }
+        }
+
+        // The other special case is two adjacent cells with no
+        // selection: [ B][E ] or [ E][B ]
+        let adjacent = tail.line == front.line && tail.col - front.col == Column(1);
+        if adjacent && front_side == Side::Right && tail_side == Side::Left {
+            return None;
+        }
+
+        Some(match (front_side, tail_side) {
+            // [FX][XX][XT]
+            (Side::Left, Side::Right) => Span {
+                cols: cols,
+                front: front,
+                tail: tail,
+                ty: SpanType::Inclusive
+            },
+            // [ F][XX][T ]
+            (Side::Right, Side::Left) => Span {
+                cols: cols,
+                front: front,
+                tail: tail,
+                ty: SpanType::Exclusive
+            },
+            // [FX][XX][T ]
+            (Side::Left, Side::Left) => Span {
+                cols: cols,
+                front: front,
+                tail: tail,
+                ty: SpanType::ExcludeTail
+            },
+            // [ F][XX][XT]
+            (Side::Right, Side::Right) => Span {
+                cols: cols,
+                front: front,
+                tail: tail,
+                ty: SpanType::ExcludeFront
+            },
+        })
+    }
 }
 
 /// How to interpret the locations of a Span.
@@ -177,20 +321,21 @@ pub enum SpanType {
 pub struct Span {
     front: Point,
     tail: Point,
+    cols: Column,
 
     /// The type says whether ends are included or not.
     ty: SpanType,
 }
 
 impl Span {
-    pub fn to_locations(&self, cols: Column) -> (Point, Point) {
+    pub fn to_locations(&self) -> (Point, Point) {
         match self.ty {
             SpanType::Inclusive => (self.front, self.tail),
             SpanType::Exclusive => {
-                (Span::wrap_start(self.front, cols), Span::wrap_end(self.tail, cols))
+                (Span::wrap_start(self.front, self.cols), Span::wrap_end(self.tail, self.cols))
             },
-            SpanType::ExcludeFront => (Span::wrap_start(self.front, cols), self.tail),
-            SpanType::ExcludeTail => (self.front, Span::wrap_end(self.tail, cols))
+            SpanType::ExcludeFront => (Span::wrap_start(self.front, self.cols), self.tail),
+            SpanType::ExcludeTail => (self.front, Span::wrap_end(self.tail, self.cols))
         }
     }
 
@@ -236,7 +381,8 @@ impl Span {
 }
 
 impl ToRange for Span {
-    fn to_range(&self, cols: Column) -> RangeInclusive<Linear> {
+    fn to_range(&self) -> RangeInclusive<Linear> {
+        let cols = self.cols;
         let start = Linear(self.front.line.0 * cols.0 + self.front.col.0);
         let end = Linear(self.tail.line.0 * cols.0 + self.tail.col.0);
 
@@ -273,7 +419,7 @@ mod test {
     #[test]
     fn single_cell_left_to_right() {
         let location = Point { line: Line(0), col: Column(0) };
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(1), Column(1));
         selection.update(location, Side::Left);
         selection.update(location, Side::Right);
 
@@ -292,7 +438,7 @@ mod test {
     #[test]
     fn single_cell_right_to_left() {
         let location = Point { line: Line(0), col: Column(0) };
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(1), Column(1));
         selection.update(location, Side::Right);
         selection.update(location, Side::Left);
 
@@ -310,7 +456,7 @@ mod test {
     /// 3. [ B][E ]
     #[test]
     fn between_adjacent_cells_left_to_right() {
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(1), Column(2));
         selection.update(Point::new(Line(0), Column(0)), Side::Right);
         selection.update(Point::new(Line(0), Column(1)), Side::Left);
 
@@ -324,7 +470,7 @@ mod test {
     /// 3. [ E][B ]
     #[test]
     fn between_adjacent_cells_right_to_left() {
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(1), Column(2));
         selection.update(Point::new(Line(0), Column(1)), Side::Left);
         selection.update(Point::new(Line(0), Column(0)), Side::Right);
 
@@ -342,7 +488,7 @@ mod test {
     ///     [XX][XB][  ][  ][  ]
     #[test]
     fn across_adjacent_lines_upward_final_cell_exclusive() {
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(2), Column(5));
         selection.update(Point::new(Line(1), Column(1)), Side::Right);
         selection.update(Point::new(Line(0), Column(1)), Side::Right);
 
@@ -366,7 +512,7 @@ mod test {
     ///     [XE][  ][  ][  ][  ]
     #[test]
     fn selection_bigger_then_smaller() {
-        let mut selection = Selection::Empty;
+        let mut selection = Selection::new(Line(2), Column(5));
         selection.update(Point::new(Line(0), Column(1)), Side::Right);
         selection.update(Point::new(Line(1), Column(1)), Side::Right);
         selection.update(Point::new(Line(1), Column(0)), Side::Right);
diff --git a/src/term/mod.rs b/src/term/mod.rs
index bbc3f1aa..1a79d309 100644
--- a/src/term/mod.rs
+++ b/src/term/mod.rs
@@ -25,7 +25,7 @@ use unicode_width::UnicodeWidthChar;
 use ansi::{self, Color, NamedColor, Attr, Handler, CharsetIndex, StandardCharset, CursorStyle};
 use grid::{BidirectionalIterator, Grid, ClearRegion, ToRange, Indexed};
 use index::{self, Point, Column, Line, Linear, IndexRange, Contains, RangeInclusive, Side};
-use selection::{Span, Selection};
+use selection::{self, Span, Selection};
 use config::{Config, VisualBellAnimation};
 use Rgb;
 
@@ -34,6 +34,55 @@ pub mod color;
 pub use self::cell::Cell;
 use self::cell::LineLength;
 
+impl<'a> selection::SemanticSearch for &'a Term {
+    fn semantic_search_left(&self, mut point: Point) -> Point {
+        let mut iter = self.grid.iter_from(point);
+        let last_col = self.grid.num_cols() - Column(1);
+
+        while let Some(cell) = iter.prev() {
+            if self.semantic_escape_chars.contains(cell.c) {
+                break;
+            }
+
+            if iter.cur.col == last_col && !cell.flags.contains(cell::WRAPLINE) {
+                break; // cut off if on new line or hit escape char
+            }
+
+            point = iter.cur;
+        }
+
+        point
+    }
+
+    fn semantic_search_right(&self, mut point: Point) -> Point {
+        let mut iter = self.grid.iter_from(point);
+        let last_col = self.grid.num_cols() - Column(1);
+
+        while let Some(cell) = iter.next() {
+            if self.semantic_escape_chars.contains(cell.c) {
+                break;
+            }
+
+            point = iter.cur;
+
+            if iter.cur.col == last_col && !cell.flags.contains(cell::WRAPLINE) {
+                break; // cut off if on new line or hit escape char
+            }
+        }
+
+        point
+    }
+}
+
+impl<'a> selection::Dimensions for &'a Term {
+    fn dimensions(&self) -> Point {
+        Point {
+            col: self.grid.num_cols(),
+            line: self.grid.num_lines()
+        }
+    }
+}
+
 /// Iterator that yields cells needing render
 ///
 /// Yields cells that require work to be displayed (that is, not a an empty
@@ -66,12 +115,9 @@ impl<'a> RenderableCellsIter<'a> {
         colors: &'b color::List,
         mode: TermMode,
         config: &'b Config,
-        selection: &Selection,
+        selection: Option<RangeInclusive<index::Linear>>,
         cursor_style: CursorStyle,
     ) -> RenderableCellsIter<'b> {
-        let selection = selection.span()
-            .map(|span| span.to_range(grid.num_cols()));
-
         let cursor_index = Linear(cursor.line.0 * grid.num_cols().0 + cursor.col.0);
 
         RenderableCellsIter {
@@ -737,64 +783,6 @@ impl Term {
         self.dirty
     }
 
-    pub fn line_selection(&self, selection: &mut Selection, point: Point) {
-        selection.clear();
-        selection.update(Point {
-            line: point.line,
-            col: Column(0),
-        }, Side::Left);
-        selection.update(Point {
-            line: point.line,
-            col: self.grid.num_cols() - Column(1),
-        }, Side::Right);
-    }
-
-    pub fn semantic_selection(&self, selection: &mut Selection, point: Point) {
-        let mut side_left = Point {
-            line: point.line,
-            col: point.col
-        };
-        let mut side_right = Point {
-            line: point.line,
-            col: point.col
-        };
-
-        let mut left_iter = self.grid.iter_from(point);
-        let mut right_iter = self.grid.iter_from(point);
-
-        let last_col = self.grid.num_cols() - Column(1);
-
-        while let Some(cell) = left_iter.prev() {
-            if self.semantic_escape_chars.contains(cell.c) {
-                break;
-            }
-
-            if left_iter.cur.col == last_col && !cell.flags.contains(cell::WRAPLINE) {
-                break; // cut off if on new line or hit escape char
-            }
-
-            side_left.col = left_iter.cur.col;
-            side_left.line = left_iter.cur.line;
-        }
-
-        while let Some(cell) = right_iter.next() {
-            if self.semantic_escape_chars.contains(cell.c) {
-                break;
-            }
-
-            side_right.col = right_iter.cur.col;
-            side_right.line = right_iter.cur.line;
-
-            if right_iter.cur.col == last_col && !cell.flags.contains(cell::WRAPLINE) {
-                break; // cut off if on new line or hit escape char
-            }
-        }
-
-        selection.clear();
-        selection.update(side_left, Side::Left);
-        selection.update(side_right, Side::Right);
-    }
-
     pub fn string_from_selection(&self, span: &Span) -> String {
         /// Need a generic push() for the Append trait
         trait PushChar {
@@ -882,7 +870,7 @@ impl Term {
 
         let mut res = String::new();
 
-        let (start, end) = span.to_locations(self.grid.num_cols());
+        let (start, end) = span.to_locations();
         let line_count = end.line - start.line;
 
         match line_count {
@@ -944,8 +932,11 @@ impl Term {
     pub fn renderable_cells<'b>(
         &'b self,
         config: &'b Config,
-        selection: &'b Selection
+        selection: Option<&'b Selection>,
     ) -> RenderableCellsIter {
+        let selection = selection.and_then(|s| s.to_span(self))
+            .map(|span| span.to_range());
+
         RenderableCellsIter::new(
             &self.grid,
             &self.cursor.point,
@@ -1850,19 +1841,19 @@ mod tests {
         mem::swap(&mut term.semantic_escape_chars, &mut escape_chars);
 
         {
-            let mut selection = Selection::new();
+            let mut selection = Selection::new(grid.num_lines(), grid.num_cols());
             term.semantic_selection(&mut selection, Point { line: Line(0), col: Column(1) });
             assert_eq!(term.string_from_selection(&selection.span().unwrap()), "aa");
         }
 
         {
-            let mut selection = Selection::new();
+            let mut selection = Selection::new(grid.num_lines(), grid.num_cols());
             term.semantic_selection(&mut selection, Point { line: Line(0), col: Column(4) });
             assert_eq!(term.string_from_selection(&selection.span().unwrap()), "aaa");
         }
 
         {
-            let mut selection = Selection::new();
+            let mut selection = Selection::new(grid.num_lines(), grid.num_cols());
             term.semantic_selection(&mut selection, Point { line: Line(1), col: Column(1) });
             assert_eq!(term.string_from_selection(&selection.span().unwrap()), "aaa");
         }
@@ -1889,7 +1880,7 @@ mod tests {
 
         mem::swap(&mut term.grid, &mut grid);
 
-        let mut selection = Selection::new();
+        let mut selection = Selection::new(grid.num_lines(), grid.num_cols());
         term.line_selection(&mut selection, Point { line: Line(0), col: Column(3) });
         match selection.span() {
             Some(span) => assert_eq!(term.string_from_selection(&span), "\"aa\"a"),
@@ -1944,7 +1935,6 @@ mod benches {
     use std::path::Path;
 
     use grid::Grid;
-    use selection::Selection;
     use config::Config;
 
     use super::{SizeInfo, Term};
@@ -1983,13 +1973,12 @@ mod benches {
         let size: SizeInfo = json::from_str(&serialized_size).unwrap();
 
         let config = Config::default();
-        let selection = Selection::Empty;
 
         let mut terminal = Term::new(&config, size);
         mem::swap(&mut terminal.grid, &mut grid);
 
         b.iter(|| {
-            let iter = terminal.renderable_cells(&config, &selection);
+            let iter = terminal.renderable_cells(&config, None);
             for cell in iter {
                 test::black_box(cell);
             }