Implement the f/t/F/T find/till family of commands.

4 files changed, 118 insertions, 11 deletions

diff --git a/TODO.md b/TODO.md
index 72ceaadc..f65a3536 100644
--- a/TODO.md
+++ b/TODO.md
@@ -25,7 +25,7 @@
 - [ ] CI binary builds
 
 - [ ] regex search / select next
-- [ ] f / t mappings
+- [x] f / t mappings
 - [ ] open_above (O) command
 - [ ] = for auto indent line/selection
 - [x] q should only close the view, if all are closed, close the editor
diff --git a/helix-core/src/search.rs b/helix-core/src/search.rs
index c03f60df..af754ab7 100644
--- a/helix-core/src/search.rs
+++ b/helix-core/src/search.rs
@@ -1,6 +1,12 @@
 use crate::RopeSlice;
 
-pub fn find_nth_next(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Option<usize> {
+pub fn find_nth_next(
+    text: RopeSlice,
+    ch: char,
+    mut pos: usize,
+    n: usize,
+    inclusive: bool,
+) -> Option<usize> {
     // start searching right after pos
     let mut chars = text.chars_at(pos + 1);
 
@@ -16,10 +22,20 @@ pub fn find_nth_next(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Opt
         }
     }
 
+    if !inclusive {
+        pos -= 1;
+    }
+
     Some(pos)
 }
 
-pub fn find_nth_prev(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Option<usize> {
+pub fn find_nth_prev(
+    text: RopeSlice,
+    ch: char,
+    mut pos: usize,
+    n: usize,
+    inclusive: bool,
+) -> Option<usize> {
     // start searching right before pos
     let mut chars = text.chars_at(pos.saturating_sub(1));
 
@@ -35,5 +51,9 @@ pub fn find_nth_prev(text: RopeSlice, ch: char, mut pos: usize, n: usize) -> Opt
         }
     }
 
+    if !inclusive {
+        pos -= 1;
+    }
+
     Some(pos)
 }
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index f60f646e..edc38a48 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -5,7 +5,7 @@ use helix_core::{
     regex::{self, Regex},
     register, search, selection,
     state::{coords_at_pos, pos_at_coords, Direction, Granularity, State},
-    Change, ChangeSet, Position, Range, Selection, Tendril, Transaction,
+    Change, ChangeSet, Position, Range, RopeSlice, Selection, Tendril, Transaction,
 };
 
 use once_cell::sync::Lazy;
@@ -236,7 +236,13 @@ pub fn extend_next_word_end(cx: &mut Context) {
     doc.set_selection(selection);
 }
 
-pub fn find_next_char(cx: &mut Context) {
+#[inline]
+fn _find_char<F>(cx: &mut Context, search_fn: F, inclusive: bool, extend: bool)
+where
+    // TODO: make an options struct for and abstract this Fn into a searcher type
+    // use the definition for w/b/e too
+    F: Fn(RopeSlice, char, usize, usize, bool) -> Option<usize>,
+{
     // TODO: count is reset to 1 before next key so we move it into the closure here.
     // Would be nice to carry over.
     let count = cx.count;
@@ -252,9 +258,13 @@ pub fn find_next_char(cx: &mut Context) {
             let text = doc.text().slice(..);
 
             let selection = doc.selection().transform(|mut range| {
-                if let Some(pos) = search::find_nth_next(text, ch, range.head, count) {
-                    Range::new(range.head, pos)
-                    // or (range.anchor, pos) for extend
+                if let Some(pos) = search::find_nth_next(text, ch, range.head, count, inclusive) {
+                    if extend {
+                        Range::new(range.anchor, pos)
+                    } else {
+                        // select
+                        Range::new(range.head, pos)
+                    }
                     // or (pos, pos) to move to found val
                 } else {
                     range
@@ -266,6 +276,78 @@ pub fn find_next_char(cx: &mut Context) {
     })
 }
 
+pub fn find_till_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_next,
+        false, /* inclusive */
+        false, /* extend */
+    )
+}
+
+pub fn find_next_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_next,
+        true,  /* inclusive */
+        false, /* extend */
+    )
+}
+
+pub fn extend_till_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_next,
+        false, /* inclusive */
+        true,  /* extend */
+    )
+}
+
+pub fn extend_next_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_next,
+        true, /* inclusive */
+        true, /* extend */
+    )
+}
+
+pub fn till_prev_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_prev,
+        false, /* inclusive */
+        false, /* extend */
+    )
+}
+
+pub fn find_prev_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_prev,
+        true,  /* inclusive */
+        false, /* extend */
+    )
+}
+
+pub fn extend_till_prev_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_prev,
+        false, /* inclusive */
+        true,  /* extend */
+    )
+}
+
+pub fn extend_prev_char(cx: &mut Context) {
+    _find_char(
+        cx,
+        search::find_nth_prev,
+        true, /* inclusive */
+        true, /* extend */
+    )
+}
+
 fn scroll(view: &mut View, offset: usize, direction: Direction) {
     use Direction::*;
     let text = view.doc.text().slice(..);
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index d956679a..58a465fe 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -137,10 +137,10 @@ pub fn default() -> Keymaps {
         key!('k') => commands::move_line_up,
         key!('l') => commands::move_char_right,
 
-        // key!('t') => commands::till_next_char,
+        key!('t') => commands::find_till_char,
         key!('f') => commands::find_next_char,
-        // key!('T') => commands::till_prev_char,
-        // key!('f') => commands::find_prev_char,
+        shift!('T') => commands::till_prev_char,
+        shift!('F') => commands::find_prev_char,
         // and matching set for select mode (extend)
 
         key!('0') => commands::move_line_start,
@@ -261,6 +261,11 @@ pub fn default() -> Keymaps {
             key!('b') => commands::extend_prev_word_start,
             key!('e') => commands::extend_next_word_end,
 
+            key!('t') => commands::extend_till_char,
+            key!('f') => commands::extend_next_char,
+            shift!('T') => commands::extend_till_prev_char,
+            shift!('F') => commands::extend_prev_char,
+
             Key {
                 code: KeyCode::Esc,
                 modifiers: Modifiers::NONE