Remove need for step_by feature

4 files changed, 50 insertions, 38 deletions

diff --git a/src/grid.rs b/src/grid.rs
index 77fe92b9..c5a7f70e 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -27,7 +27,7 @@ use std::ops::{Deref, DerefMut, Range, RangeTo, RangeFrom, RangeFull, Index, Ind
 use std::ops::RangeInclusive;
 use std::slice::{self, Iter, IterMut};
 
-use index::{self, Point};
+use index::{self, Point, IndexRange};
 
 /// Convert a type to a linear index range.
 pub trait ToRange {
@@ -53,7 +53,7 @@ pub struct Grid<T> {
 impl<T: Clone> Grid<T> {
     pub fn new(lines: index::Line, cols: index::Column, template: &T) -> Grid<T> {
         let mut raw = Vec::with_capacity(*lines);
-        for _ in index::Line(0)..lines {
+        for _ in IndexRange(index::Line(0)..lines) {
             raw.push(Row::new(cols, template));
         }
 
@@ -84,7 +84,7 @@ impl<T: Clone> Grid<T> {
     }
 
     fn grow_lines(&mut self, lines: index::Line, template: &T) {
-        for _ in self.num_lines()..lines {
+        for _ in IndexRange(self.num_lines()..lines) {
             self.raw.push(Row::new(self.cols, template));
         }
 
@@ -124,7 +124,7 @@ impl<T> Grid<T> {
 
     #[inline]
     pub fn scroll_down(&mut self, region: Range<index::Line>, positions: index::Line) {
-        for line in region.rev() {
+        for line in IndexRange(region).rev() {
             let src = line;
             let dst = line - positions;
             self.swap_lines(src, dst);
@@ -133,7 +133,7 @@ impl<T> Grid<T> {
 
     #[inline]
     pub fn scroll_up(&mut self, region: Range<index::Line>, positions: index::Line) {
-        for line in region {
+        for line in IndexRange(region) {
             let src = line;
             let dst = line + positions;
             self.swap_lines(src, dst);
diff --git a/src/index.rs b/src/index.rs
index c80589da..b1f6f452 100644
--- a/src/index.rs
+++ b/src/index.rs
@@ -17,9 +17,7 @@
 /// Indexing types and implementations for Grid and Line
 use std::cmp::{Ord, Ordering};
 use std::fmt;
-use std::iter::Step;
-use std::mem;
-use std::ops::{self, Deref, Add};
+use std::ops::{self, Deref, Add, Range};
 
 /// The side of a cell
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
@@ -200,6 +198,18 @@ macro_rules! sub {
     }
 }
 
+/// This exists because we can't implement Iterator on Range
+/// and the existing impl needs the unstable Step trait
+/// This should be removed and replaced with a Step impl
+/// in the ops macro when `step_by` is stabilized
+pub struct IndexRange<T>(pub Range<T>);
+
+impl<T> From<Range<T>> for IndexRange<T> {
+    fn from(from: Range<T>) -> Self {
+        IndexRange(from)
+    }
+}
+
 macro_rules! ops {
     ($ty:ty, $construct:expr) => {
         add!($ty, $construct);
@@ -207,12 +217,7 @@ macro_rules! ops {
         deref!($ty, usize);
         forward_ref_binop!(impl Add, add for $ty, $ty);
 
-        impl Step for $ty {
-            #[inline]
-            fn step(&self, by: &$ty) -> Option<$ty> {
-                Some(*self + *by)
-            }
-
+        impl $ty {
             #[inline]
             #[allow(trivial_numeric_casts)]
             fn steps_between(start: &$ty, end: &$ty, by: &$ty) -> Option<usize> {
@@ -233,33 +238,41 @@ macro_rules! ops {
 
             #[inline]
             fn steps_between_by_one(start: &$ty, end: &$ty) -> Option<usize> {
-                Step::steps_between(start, end, &$construct(1))
-            }
-
-            #[inline]
-            #[allow(unused_comparisons)]
-            fn is_negative(&self) -> bool {
-                self.0 < 0
-            }
-
-            #[inline]
-            fn replace_one(&mut self) -> Self {
-                mem::replace(self, $construct(0))
+                Self::steps_between(start, end, &$construct(1))
             }
+        }
 
+        impl Iterator for IndexRange<$ty> {
+            type Item = $ty;
             #[inline]
-            fn replace_zero(&mut self) -> Self {
-                mem::replace(self, $construct(1))
+            fn next(&mut self) -> Option<$ty> {
+                if self.0.start < self.0.end {
+                    let old = self.0.start;
+                    self.0.start = old + 1;
+                    Some(old)
+                } else {
+                    None
+                }
             }
-
             #[inline]
-            fn add_one(&self) -> Self {
-                *self + 1
+            fn size_hint(&self) -> (usize, Option<usize>) {
+                match Self::Item::steps_between_by_one(&self.0.start, &self.0.end) {
+                    Some(hint) => (hint, Some(hint)),
+                    None => (0, None)
+                }
             }
+        }
 
+        impl DoubleEndedIterator for IndexRange<$ty> {
             #[inline]
-            fn sub_one(&self) -> Self {
-                *self - 1
+            fn next_back(&mut self) -> Option<$ty> {
+                if self.0.start < self.0.end {
+                    let new = self.0.end - 1;
+                    self.0.end = new;
+                    Some(new)
+                } else {
+                    None
+                }
             }
         }
 
diff --git a/src/lib.rs b/src/lib.rs
index 04e738d8..fdfe5f59 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -17,7 +17,6 @@
 #![feature(inclusive_range_syntax)]
 #![feature(inclusive_range)]
 #![feature(drop_types_in_const)]
-#![feature(step_trait)]
 #![cfg_attr(feature = "clippy", feature(plugin))]
 #![cfg_attr(feature = "clippy", plugin(clippy))]
 #![cfg_attr(feature = "clippy", deny(clippy))]
diff --git a/src/term/mod.rs b/src/term/mod.rs
index 690c2f10..4c2afc35 100644
--- a/src/term/mod.rs
+++ b/src/term/mod.rs
@@ -20,7 +20,7 @@ use std::io;
 
 use ansi::{self, Color, NamedColor, Attr, Handler};
 use grid::{Grid, ClearRegion, ToRange};
-use index::{self, Point, Column, Line, Linear};
+use index::{self, Point, Column, Line, Linear, IndexRange};
 use selection::{Span, Selection};
 
 pub mod cell;
@@ -286,7 +286,7 @@ impl Term {
 
         let grid = Grid::new(num_lines, num_cols, &template);
 
-        let mut tabs = (Column(0)..grid.num_cols())
+        let mut tabs = IndexRange::from(Column(0)..grid.num_cols())
             .map(|i| (*i as usize) % TAB_SPACES == 0)
             .collect::<Vec<bool>>();
 
@@ -424,7 +424,7 @@ impl Term {
                 // Starting line
                 res.append(&self.grid, start.line, start.col..);
 
-                let middle_range = (start.line + 1)..(end.line);
+                let middle_range = IndexRange::from((start.line + 1)..(end.line));
                 for line in middle_range {
                     res.append(&self.grid, line, ..);
                 }
@@ -507,7 +507,7 @@ impl Term {
         self.cursor.col = limit(self.cursor.col, Column(0), num_cols);
 
         // Recreate tabs list
-        self.tabs = (Column(0)..self.grid.num_cols())
+        self.tabs = IndexRange::from(Column(0)..self.grid.num_cols())
             .map(|i| (*i as usize) % TAB_SPACES == 0)
             .collect::<Vec<bool>>();