Move grid Row and tests into submodules

This is part of some cleanup for the grid module as a whole.

3 files changed, 869 insertions, 0 deletions

diff --git a/src/grid/mod.rs b/src/grid/mod.rs
new file mode 100644
index 00000000..123e13fa
--- /dev/null
+++ b/src/grid/mod.rs
@@ -0,0 +1,495 @@
+// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
+//
+// Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! A generic 2d grid implementation optimized for use in a terminal.
+//!
+//! The current implementation uses a vector of vectors to store cell data.
+//! Reimplementing the store as a single contiguous vector may be desirable in
+//! the future. Rotation and indexing would need to be reconsidered at that
+//! time; rotation currently reorganize Vecs in the lines Vec, and indexing with
+//! ranges is currently supported.
+
+use std::cmp::Ordering;
+use std::collections::{VecDeque, vec_deque};
+use std::iter::IntoIterator;
+use std::ops::{Deref, Range, RangeTo, RangeFrom, Index, IndexMut};
+
+use index::{self, Point, Line, Column, IndexRange, RangeInclusive};
+
+mod row;
+pub use self::row::Row;
+
+#[cfg(test)]
+mod tests;
+
+/// Convert a type to a linear index range.
+pub trait ToRange {
+    fn to_range(&self) -> RangeInclusive<index::Linear>;
+}
+
+/// Bidirection iterator
+pub trait BidirectionalIterator: Iterator {
+    fn prev(&mut self) -> Option<Self::Item>;
+}
+
+/// An item in the grid along with its Line and Column.
+pub struct Indexed<T> {
+    pub inner: T,
+    pub line: Line,
+    pub column: Column,
+}
+
+impl<T> Deref for Indexed<T> {
+    type Target = T;
+
+    #[inline]
+    fn deref(&self) -> &T {
+        &self.inner
+    }
+}
+
+/// Represents the terminal display contents
+#[derive(Clone, Debug, Deserialize, Serialize, Eq, PartialEq)]
+pub struct Grid<T> {
+    /// Lines in the grid. Each row holds a list of cells corresponding to the
+    /// columns in that row.
+    raw: VecDeque<Row<T>>,
+
+    /// Number of columns
+    cols: index::Column,
+
+    /// Number of lines.
+    ///
+    /// Invariant: lines is equivalent to raw.len()
+    lines: index::Line,
+}
+
+pub struct GridIterator<'a, T: 'a> {
+    grid: &'a Grid<T>,
+    pub cur: Point,
+}
+
+impl<T: Clone> Grid<T> {
+    pub fn new(lines: index::Line, cols: index::Column, template: &T) -> Grid<T> {
+        let mut raw = VecDeque::with_capacity(*lines);
+        for _ in IndexRange(index::Line(0)..lines) {
+            raw.push_back(Row::new(cols, template));
+        }
+
+        Grid {
+            raw,
+            cols,
+            lines,
+        }
+    }
+
+    pub fn resize(&mut self, lines: index::Line, cols: index::Column, template: &T) {
+        // Check that there's actually work to do and return early if not
+        if lines == self.lines && cols == self.cols {
+            return;
+        }
+
+        match self.lines.cmp(&lines) {
+            Ordering::Less => self.grow_lines(lines, template),
+            Ordering::Greater => self.shrink_lines(lines),
+            Ordering::Equal => (),
+        }
+
+        match self.cols.cmp(&cols) {
+            Ordering::Less => self.grow_cols(cols, template),
+            Ordering::Greater => self.shrink_cols(cols),
+            Ordering::Equal => (),
+        }
+    }
+
+    fn grow_lines(&mut self, lines: index::Line, template: &T) {
+        for _ in IndexRange(self.num_lines()..lines) {
+            self.raw.push_back(Row::new(self.cols, template));
+        }
+
+        self.lines = lines;
+    }
+
+    fn grow_cols(&mut self, cols: index::Column, template: &T) {
+        for row in self.lines_mut() {
+            row.grow(cols, template);
+        }
+
+        self.cols = cols;
+    }
+
+}
+
+
+
+impl<T> Grid<T> {
+    #[inline]
+    pub fn lines(&self) -> vec_deque::Iter<Row<T>> {
+        self.raw.iter()
+    }
+
+    #[inline]
+    pub fn lines_mut(&mut self) -> vec_deque::IterMut<Row<T>> {
+        self.raw.iter_mut()
+    }
+
+    #[inline]
+    pub fn num_lines(&self) -> index::Line {
+        self.lines
+    }
+
+    #[inline]
+    pub fn num_cols(&self) -> index::Column {
+        self.cols
+    }
+
+    #[inline]
+    pub fn scroll_down(&mut self, region: &Range<index::Line>, positions: index::Line) {
+        if region.start == Line(0) && region.end == self.num_lines() {
+            // Full rotation
+            for _ in 0..positions.0 {
+                let item = self.raw.pop_back().unwrap();
+                self.raw.push_front(item);
+            }
+        } else {
+            // Subregion rotation
+            for line in IndexRange((region.start + positions)..region.end).rev() {
+                self.swap_lines(line, line - positions);
+            }
+        }
+    }
+
+    #[inline]
+    pub fn scroll_up(&mut self, region: &Range<index::Line>, positions: index::Line) {
+        if region.start == Line(0) && region.end == self.num_lines() {
+            // Full rotation
+            for _ in 0..positions.0 {
+                let item = self.raw.pop_front().unwrap();
+                self.raw.push_back(item);
+            }
+        } else {
+            // Subregion rotation
+            for line in IndexRange(region.start..(region.end - positions)) {
+                self.swap_lines(line, line + positions);
+            }
+        }
+    }
+
+    pub fn iter_from(&self, point: Point) -> GridIterator<T> {
+        GridIterator {
+            grid: self,
+            cur: point,
+        }
+    }
+
+    #[inline]
+    pub fn contains(&self, point: &Point) -> bool {
+        self.lines > point.line && self.cols > point.col
+    }
+
+    /// Swap two lines in the grid
+    ///
+    /// This could have used slice::swap internally, but we are able to have
+    /// better error messages by doing the bounds checking ourselves.
+    #[inline]
+    pub fn swap_lines(&mut self, src: index::Line, dst: index::Line) {
+        self.raw.swap(*src, *dst);
+    }
+
+    #[inline]
+    pub fn clear<F: Fn(&mut T)>(&mut self, func: F) {
+        let region = index::Line(0)..self.num_lines();
+        self.clear_region(region, func);
+    }
+
+    fn shrink_lines(&mut self, lines: index::Line) {
+        while index::Line(self.raw.len()) != lines {
+            self.raw.pop_back();
+        }
+
+        self.lines = lines;
+    }
+
+    fn shrink_cols(&mut self, cols: index::Column) {
+        for row in self.lines_mut() {
+            row.shrink(cols);
+        }
+
+        self.cols = cols;
+    }
+}
+
+impl<'a, T> Iterator for GridIterator<'a, T> {
+    type Item = &'a T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let last_line = self.grid.num_lines() - Line(1);
+        let last_col = self.grid.num_cols() - Column(1);
+        match self.cur {
+            Point { line, col } if
+                (line == last_line) &&
+                (col == last_col) => None,
+            Point { col, .. } if
+                (col == last_col) => {
+                self.cur.line += Line(1);
+                self.cur.col = Column(0);
+                Some(&self.grid[self.cur.line][self.cur.col])
+            },
+            _ => {
+                self.cur.col += Column(1);
+                Some(&self.grid[self.cur.line][self.cur.col])
+            }
+        }
+    }
+}
+
+impl<'a, T> BidirectionalIterator for GridIterator<'a, T> {
+    fn prev(&mut self) -> Option<Self::Item> {
+        let num_cols = self.grid.num_cols();
+
+        match self.cur {
+            Point { line: Line(0), col: Column(0) } => None,
+            Point { col: Column(0), .. } => {
+                self.cur.line -= Line(1);
+                self.cur.col = num_cols - Column(1);
+                Some(&self.grid[self.cur.line][self.cur.col])
+            },
+            _ => {
+                self.cur.col -= Column(1);
+                Some(&self.grid[self.cur.line][self.cur.col])
+            }
+        }
+    }
+}
+
+impl<T> Index<index::Line> for Grid<T> {
+    type Output = Row<T>;
+
+    #[inline]
+    fn index(&self, index: index::Line) -> &Row<T> {
+        &self.raw[index.0]
+    }
+}
+
+impl<T> IndexMut<index::Line> for Grid<T> {
+    #[inline]
+    fn index_mut(&mut self, index: index::Line) -> &mut Row<T> {
+        &mut self.raw[index.0]
+    }
+}
+
+impl<'point, T> Index<&'point Point> for Grid<T> {
+    type Output = T;
+
+    #[inline]
+    fn index<'a>(&'a self, point: &Point) -> &'a T {
+        &self.raw[point.line.0][point.col]
+    }
+}
+
+impl<'point, T> IndexMut<&'point Point> for Grid<T> {
+    #[inline]
+    fn index_mut<'a, 'b>(&'a mut self, point: &'b Point) -> &'a mut T {
+        &mut self.raw[point.line.0][point.col]
+    }
+}
+
+impl<'a, T> IntoIterator for &'a Grid<T> {
+    type Item = &'a Row<T>;
+    type IntoIter = vec_deque::Iter<'a, Row<T>>;
+
+    #[inline]
+    fn into_iter(self) -> vec_deque::Iter<'a, Row<T>> {
+        self.raw.iter()
+    }
+}
+
+pub trait ClearRegion<R, T> {
+    fn clear_region<F: Fn(&mut T)>(&mut self, region: R, func: F);
+}
+
+macro_rules! clear_region_impl {
+    ($range:ty) => {
+        impl<T> ClearRegion<$range, T> for Grid<T> {
+            fn clear_region<F: Fn(&mut T)>(&mut self, region: $range, func: F) {
+                for row in self.region_mut(region) {
+                    for cell in row {
+                        func(cell);
+                    }
+                }
+            }
+        }
+    }
+}
+
+clear_region_impl!(Range<index::Line>);
+clear_region_impl!(RangeTo<index::Line>);
+clear_region_impl!(RangeFrom<index::Line>);
+
+// =================================================================================================
+// Regions =========================================================================================
+// =================================================================================================
+
+/// A subset of lines in the grid
+///
+/// May be constructed using Grid::region(..)
+pub struct Region<'a, T: 'a> {
+    start: Line,
+    end: Line,
+    raw: &'a VecDeque<Row<T>>,
+}
+
+/// A mutable subset of lines in the grid
+///
+/// May be constructed using Grid::region_mut(..)
+pub struct RegionMut<'a, T: 'a> {
+    start: Line,
+    end: Line,
+    raw: &'a mut VecDeque<Row<T>>,
+}
+
+pub trait IndexRegion<I, T> {
+    /// Get an immutable region of Self
+    fn region<'a>(&'a self, _: I) -> Region<'a, T>;
+
+    /// Get a mutable region of Self
+    fn region_mut<'a>(&'a mut self, _: I) -> RegionMut<'a, T>;
+}
+
+impl<T> IndexRegion<Range<Line>, T> for Grid<T> {
+    fn region(&self, index: Range<Line>) -> Region<T> {
+        assert!(index.start < self.num_lines());
+        assert!(index.end <= self.num_lines());
+        assert!(index.start <= index.end);
+        Region {
+            start: index.start,
+            end: index.end,
+            raw: &self.raw
+        }
+    }
+    fn region_mut(&mut self, index: Range<Line>) -> RegionMut<T> {
+        assert!(index.start < self.num_lines());
+        assert!(index.end <= self.num_lines());
+        assert!(index.start <= index.end);
+        RegionMut {
+            start: index.start,
+            end: index.end,
+            raw: &mut self.raw
+        }
+    }
+}
+
+impl<T> IndexRegion<RangeTo<Line>, T> for Grid<T> {
+    fn region(&self, index: RangeTo<Line>) -> Region<T> {
+        assert!(index.end <= self.num_lines());
+        Region {
+            start: Line(0),
+            end: index.end,
+            raw: &self.raw
+        }
+    }
+    fn region_mut(&mut self, index: RangeTo<Line>) -> RegionMut<T> {
+        assert!(index.end <= self.num_lines());
+        RegionMut {
+            start: Line(0),
+            end: index.end,
+            raw: &mut self.raw
+        }
+    }
+}
+
+impl<T> IndexRegion<RangeFrom<Line>, T> for Grid<T> {
+    fn region(&self, index: RangeFrom<Line>) -> Region<T> {
+        assert!(index.start < self.num_lines());
+        Region {
+            start: index.start,
+            end: self.num_lines(),
+            raw: &self.raw
+        }
+    }
+    fn region_mut(&mut self, index: RangeFrom<Line>) -> RegionMut<T> {
+        assert!(index.start < self.num_lines());
+        RegionMut {
+            start: index.start,
+            end: self.num_lines(),
+            raw: &mut self.raw
+        }
+    }
+}
+
+pub struct RegionIter<'a, T: 'a> {
+    end: Line,
+    cur: Line,
+    raw: &'a VecDeque<Row<T>>,
+}
+
+pub struct RegionIterMut<'a, T: 'a> {
+    end: Line,
+    cur: Line,
+    raw: &'a mut VecDeque<Row<T>>,
+}
+
+impl<'a, T> IntoIterator for Region<'a, T> {
+    type Item = &'a Row<T>;
+    type IntoIter = RegionIter<'a, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        RegionIter {
+            end: self.end,
+            cur: self.start,
+            raw: self.raw
+        }
+    }
+}
+
+impl<'a, T> IntoIterator for RegionMut<'a, T> {
+    type Item = &'a mut Row<T>;
+    type IntoIter = RegionIterMut<'a, T>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        RegionIterMut {
+            end: self.end,
+            cur: self.start,
+            raw: self.raw
+        }
+    }
+}
+
+impl<'a, T> Iterator for RegionIter<'a, T> {
+    type Item = &'a Row<T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.cur < self.end {
+            let index = self.cur;
+            self.cur += 1;
+            Some(&self.raw[*index])
+        } else {
+            None
+        }
+    }
+}
+
+impl<'a, T> Iterator for RegionIterMut<'a, T> {
+    type Item = &'a mut Row<T>;
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.cur < self.end {
+            let index = self.cur;
+            self.cur += 1;
+            unsafe {
+                Some(&mut *(&mut self.raw[index.0] as *mut _))
+            }
+        } else {
+            None
+        }
+    }
+}
diff --git a/src/grid/row.rs b/src/grid/row.rs
new file mode 100644
index 00000000..8711d04f
--- /dev/null
+++ b/src/grid/row.rs
@@ -0,0 +1,186 @@
+// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
+//
+// Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Defines the Row type which makes up lines in the grid
+
+use std::ops::{Deref, DerefMut, Index, IndexMut};
+use std::ops::{Range, RangeTo, RangeFrom, RangeFull};
+use std::slice;
+
+use index::Column;
+
+/// A row in the grid
+#[derive(Clone, Debug, Serialize, Deserialize, Eq, PartialEq)]
+pub struct Row<T>(Vec<T>);
+
+impl<T: Clone> Row<T> {
+    pub fn new(columns: Column, template: &T) -> Row<T> {
+        Row(vec![template.to_owned(); *columns])
+    }
+
+    pub fn grow(&mut self, cols: Column, template: &T) {
+        while self.len() != *cols {
+            self.push(template.to_owned());
+        }
+    }
+}
+
+impl<T> Row<T> {
+    pub fn shrink(&mut self, cols: Column) {
+        while self.len() != *cols {
+            self.pop();
+        }
+    }
+
+    #[inline]
+    pub fn cells(&self) -> slice::Iter<T> {
+        self.0.iter()
+    }
+
+    #[inline]
+    pub fn cells_mut(&mut self) -> slice::IterMut<T> {
+        self.0.iter_mut()
+    }
+}
+
+
+impl<'a, T> IntoIterator for &'a Row<T> {
+    type Item = &'a T;
+    type IntoIter = slice::Iter<'a, T>;
+
+    #[inline]
+    fn into_iter(self) -> slice::Iter<'a, T> {
+        self.iter()
+    }
+}
+
+impl<'a, T> IntoIterator for &'a mut Row<T> {
+    type Item = &'a mut T;
+    type IntoIter = slice::IterMut<'a, T>;
+
+    #[inline]
+    fn into_iter(self) -> slice::IterMut<'a, T> {
+        self.iter_mut()
+    }
+}
+
+impl<T> Deref for Row<T> {
+    type Target = Vec<T>;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+
+impl<T> DerefMut for Row<T> {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+impl<T> Index<Column> for Row<T> {
+    type Output = T;
+
+    #[inline]
+    fn index(&self, index: Column) -> &T {
+        &self.0[index.0]
+    }
+}
+
+impl<T> IndexMut<Column> for Row<T> {
+    #[inline]
+    fn index_mut(&mut self, index: Column) -> &mut T {
+        &mut self.0[index.0]
+    }
+}
+
+macro_rules! row_index_range {
+    ($range:ty) => {
+        impl<T> Index<$range> for Row<T> {
+            type Output = [T];
+
+            #[inline]
+            fn index(&self, index: $range) -> &[T] {
+                &self.0[index]
+            }
+        }
+
+        impl<T> IndexMut<$range> for Row<T> {
+            #[inline]
+            fn index_mut(&mut self, index: $range) -> &mut [T] {
+                &mut self.0[index]
+            }
+        }
+    }
+}
+
+row_index_range!(Range<usize>);
+row_index_range!(RangeTo<usize>);
+row_index_range!(RangeFrom<usize>);
+row_index_range!(RangeFull);
+
+// -----------------------------------------------------------------------------
+// Column ranges for Row
+// -----------------------------------------------------------------------------
+
+impl<T> Index<Range<Column>> for Row<T> {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: Range<Column>) -> &[T] {
+        &self.0[(index.start.0)..(index.end.0)]
+    }
+}
+
+impl<T> IndexMut<Range<Column>> for Row<T> {
+    #[inline]
+    fn index_mut(&mut self, index: Range<Column>) -> &mut [T] {
+        &mut self.0[(index.start.0)..(index.end.0)]
+    }
+}
+
+impl<T> Index<RangeTo<Column>> for Row<T> {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: RangeTo<Column>) -> &[T] {
+        &self.0[..(index.end.0)]
+    }
+}
+
+impl<T> IndexMut<RangeTo<Column>> for Row<T> {
+    #[inline]
+    fn index_mut(&mut self, index: RangeTo<Column>) -> &mut [T] {
+        &mut self.0[..(index.end.0)]
+    }
+}
+
+impl<T> Index<RangeFrom<Column>> for Row<T> {
+    type Output = [T];
+
+    #[inline]
+    fn index(&self, index: RangeFrom<Column>) -> &[T] {
+        &self.0[(index.start.0)..]
+    }
+}
+
+impl<T> IndexMut<RangeFrom<Column>> for Row<T> {
+    #[inline]
+    fn index_mut(&mut self, index: RangeFrom<Column>) -> &mut [T] {
+        &mut self.0[(index.start.0)..]
+    }
+}
diff --git a/src/grid/tests.rs b/src/grid/tests.rs
new file mode 100644
index 00000000..169cefa0
--- /dev/null
+++ b/src/grid/tests.rs
@@ -0,0 +1,188 @@
+// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
+//
+// Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Tests for the Gird
+
+use super::{Grid, BidirectionalIterator};
+use index::{Point, Line, Column};
+
+#[test]
+fn grid_swap_lines_ok() {
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    info!("");
+
+    // swap test ends
+    grid[Line(0)][Column(0)] = 1;
+    grid[Line(9)][Column(0)] = 2;
+
+    assert_eq!(grid[Line(0)][Column(0)], 1);
+    assert_eq!(grid[Line(9)][Column(0)], 2);
+
+    grid.swap_lines(Line(0), Line(9));
+
+    assert_eq!(grid[Line(0)][Column(0)], 2);
+    assert_eq!(grid[Line(9)][Column(0)], 1);
+
+    // swap test mid
+    grid[Line(4)][Column(0)] = 1;
+    grid[Line(5)][Column(0)] = 2;
+
+    info!("grid: {:?}", grid);
+
+    assert_eq!(grid[Line(4)][Column(0)], 1);
+    assert_eq!(grid[Line(5)][Column(0)], 2);
+
+    grid.swap_lines(Line(4), Line(5));
+
+    info!("grid: {:?}", grid);
+
+    assert_eq!(grid[Line(4)][Column(0)], 2);
+    assert_eq!(grid[Line(5)][Column(0)], 1);
+}
+
+#[test]
+#[should_panic]
+fn grid_swap_lines_oob1() {
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    grid.swap_lines(Line(0), Line(10));
+}
+
+#[test]
+#[should_panic]
+fn grid_swap_lines_oob2() {
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    grid.swap_lines(Line(10), Line(0));
+}
+
+#[test]
+#[should_panic]
+fn grid_swap_lines_oob3() {
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    grid.swap_lines(Line(10), Line(10));
+}
+
+// Scroll up moves lines upwards
+#[test]
+fn scroll_up() {
+    info!("");
+
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    for i in 0..10 {
+        grid[Line(i)][Column(0)] = i;
+    }
+
+    info!("grid: {:?}", grid);
+
+    grid.scroll_up(Line(0)..Line(10), Line(2));
+
+    info!("grid: {:?}", grid);
+
+    let mut other = Grid::new(Line(10), Column(1), &9);
+
+    other[Line(0)][Column(0)] = 2;
+    other[Line(1)][Column(0)] = 3;
+    other[Line(2)][Column(0)] = 4;
+    other[Line(3)][Column(0)] = 5;
+    other[Line(4)][Column(0)] = 6;
+    other[Line(5)][Column(0)] = 7;
+    other[Line(6)][Column(0)] = 8;
+    other[Line(7)][Column(0)] = 9;
+    other[Line(8)][Column(0)] = 0;
+    other[Line(9)][Column(0)] = 1;
+
+    for i in 0..10 {
+        assert_eq!(grid[Line(i)][Column(0)], other[Line(i)][Column(0)]);
+    }
+}
+
+// Scroll down moves lines downwards
+#[test]
+fn scroll_down() {
+    info!("");
+
+    let mut grid = Grid::new(Line(10), Column(1), &0);
+    for i in 0..10 {
+        grid[Line(i)][Column(0)] = i;
+    }
+
+    info!("grid: {:?}", grid);
+
+    grid.scroll_down(Line(0)..Line(10), Line(2));
+
+    info!("grid: {:?}", grid);
+
+    let mut other = Grid::new(Line(10), Column(1), &9);
+
+    other[Line(0)][Column(0)] = 8;
+    other[Line(1)][Column(0)] = 9;
+    other[Line(2)][Column(0)] = 0;
+    other[Line(3)][Column(0)] = 1;
+    other[Line(4)][Column(0)] = 2;
+    other[Line(5)][Column(0)] = 3;
+    other[Line(6)][Column(0)] = 4;
+    other[Line(7)][Column(0)] = 5;
+    other[Line(8)][Column(0)] = 6;
+    other[Line(9)][Column(0)] = 7;
+
+    for i in 0..10 {
+        assert_eq!(grid[Line(i)][Column(0)], other[Line(i)][Column(0)]);
+    }
+}
+
+// Test that GridIterator works
+#[test]
+fn test_iter() {
+    info!("");
+
+    let mut grid = Grid::new(Line(5), Column(5), &0);
+    for i in 0..5 {
+        for j in 0..5 {
+            grid[Line(i)][Column(j)] = i*5 + j;
+        }
+    }
+
+    info!("grid: {:?}", grid);
+
+    let mut iter = grid.iter_from(Point {
+        line: Line(0),
+        col: Column(0),
+    });
+
+    assert_eq!(None, iter.prev());
+    assert_eq!(Some(&1), iter.next());
+    assert_eq!(Column(1), iter.cur.col);
+    assert_eq!(Line(0), iter.cur.line);
+
+    assert_eq!(Some(&2), iter.next());
+    assert_eq!(Some(&3), iter.next());
+    assert_eq!(Some(&4), iter.next());
+
+    // test linewrapping
+    assert_eq!(Some(&5), iter.next());
+    assert_eq!(Column(0), iter.cur.col);
+    assert_eq!(Line(1), iter.cur.line);
+
+    assert_eq!(Some(&4), iter.prev());
+    assert_eq!(Column(4), iter.cur.col);
+    assert_eq!(Line(0), iter.cur.line);
+
+
+    // test that iter ends at end of grid
+    let mut final_iter = grid.iter_from(Point {
+        line: Line(4),
+        col: Column(4),
+    });
+    assert_eq!(None, final_iter.next());
+    assert_eq!(Some(&23), final_iter.prev());
+}