feat: 5 new commands to toggle text between PascalCase, camelCase, snake_case, Title Case and kebab-case

book/src/keymap.md

@@ -11,6 +11,7 @@
     - [Goto mode](#goto-mode)
     - [Match mode](#match-mode)
     - [Window mode](#window-mode)
+    - [Case Mode](#case-mode)
     - [Space mode](#space-mode)
       - [Popup](#popup)
       - [Completion Menu](#completion-menu)
@@ -70,8 +71,6 @@ Normal mode is the default mode when you launch helix. You can return to it from
 | `r`         | Replace with a character                                             | `replace`                 |
 | `R`         | Replace with yanked text                                             | `replace_with_yanked`     |
 | `~`         | Switch case of the selected text                                     | `switch_case`             |
-| `` ` ``     | Set the selected text to lower case                                  | `switch_to_lowercase`     |
-| `` Alt-` `` | Set the selected text to upper case                                  | `switch_to_uppercase`     |
 | `i`         | Insert before selection                                              | `insert_mode`             |
 | `a`         | Insert after selection (append)                                      | `append_mode`             |
 | `I`         | Insert at the start of the line                                      | `insert_at_line_start`    |
@@ -169,6 +168,7 @@ These sub-modes are accessible from normal mode and typically switch back to nor
 | -----    | -----------                                        | -------        |
 | `v`      | Enter [select (extend) mode](#select--extend-mode) | `select_mode`  |
 | `g`      | Enter [goto mode](#goto-mode)                      | N/A            |
+| ` ` `      | Enter [case mode](#case-mode)                    | N/A            |
 | `m`      | Enter [match mode](#match-mode)                    | N/A            |
 | `:`      | Enter command mode                                 | `command_mode` |
 | `z`      | Enter [view mode](#view-mode)                      | N/A            |
@@ -232,6 +232,24 @@ Jumps to various locations.
 | `k`   | Move up textual (instead of visual) line         | `move_line_up`             |
 | `w`   | Show labels at each word and select the word that belongs to the entered labels | `goto_word` |
 
+#### Case mode
+
+Accessed by typing ` ` ` in [normal mode](#normal-mode).
+
+Various functions for changing case of text in different ways.
+
+| Key              | Description                                      | Command                    |
+| -----            | -----------                                      | -------                    |
+| `l`              | Switch all text to lowercase                     | `switch_to_lowercase`      |
+| `u`              | Switch all text to UPPERCASE                     | `switch_to_uppercase`      |
+| `p`              | Switch text to Pascal Case                       | `switch_to_pascal_case`    |
+| `c`              | Switch text to camelCase                         | `switch_to_camel_case`     |
+| `t`              | Switch text to Title Case                        | `switch_to_title_case`     |
+| `s`              | Switch text to snake_case                        | `switch_to_snake_case`     |
+| `k`              | Switch text to kebab-case                        | `switch_to_kebab_case`     |
+
+TODO: Mappings for selecting syntax nodes (a superset of `[`).
+
 #### Match mode
 
 Accessed by typing `m` in [normal mode](#normal-mode).

helix-term/Cargo.toml

@@ -35,6 +35,7 @@ helix-loader = { path = "../helix-loader" }
 anyhow = "1"
 once_cell = "1.20"
 
+heck = "0.5"
 tokio = { version = "1", features = ["rt", "rt-multi-thread", "io-util", "io-std", "time", "process", "macros", "fs", "parking_lot"] }
 tui = { path = "../helix-tui", package = "helix-tui", default-features = false, features = ["crossterm"] }
 crossterm = { version = "0.28", features = ["event-stream"] }

helix-term/src/commands.rs

@@ -51,6 +51,7 @@ use helix_view::{
 };
 
 use anyhow::{anyhow, bail, ensure, Context as _};
+use heck::{ToKebabCase, ToLowerCamelCase, ToSnakeCase, ToTitleCase, ToUpperCamelCase};
 use insert::*;
 use movement::Movement;
 
@@ -329,9 +330,14 @@ impl MappableCommand {
         extend_prev_char, "Extend to previous occurrence of char",
         repeat_last_motion, "Repeat last motion",
         replace, "Replace with new char",
-        switch_case, "Switch (toggle) case",
-        switch_to_uppercase, "Switch to uppercase",
+        switch_to_alternate_case, "Switch to aLTERNATE cASE",
+        switch_to_uppercase, "Switch to UPPERCASE",
         switch_to_lowercase, "Switch to lowercase",
+        switch_to_pascal_case, "Switch to PascalCase",
+        switch_to_camel_case, "Switch to camelCase",
+        switch_to_title_case, "Switch to Title Case",
+        switch_to_snake_case, "Switch to snake_case",
+        switch_to_kebab_case, "Switch to kebab-case",
         page_up, "Move page up",
         page_down, "Move page down",
         half_page_up, "Move half page up",
@@ -1713,7 +1719,15 @@ where
     exit_select_mode(cx);
 }
 
-fn switch_case(cx: &mut Context) {
+fn switch_heck_case_impl(cx: &mut Context, change_fn: impl Fn(Tendril) -> String) {
+    switch_case_impl(cx, |string| {
+        let stri = Tendril::from_iter(string.chars());
+        let applied = change_fn(stri);
+        Tendril::from_iter(applied.chars())
+    });
+}
+
+fn switch_to_alternate_case(cx: &mut Context) {
     switch_case_impl(cx, |string| {
         string
             .chars()
@@ -1730,6 +1744,26 @@ fn switch_case(cx: &mut Context) {
     });
 }
 
+fn switch_to_pascal_case(cx: &mut Context) {
+    switch_heck_case_impl(cx, |str| str.to_upper_camel_case())
+}
+
+fn switch_to_camel_case(cx: &mut Context) {
+    switch_heck_case_impl(cx, |str| str.to_lower_camel_case())
+}
+
+fn switch_to_title_case(cx: &mut Context) {
+    switch_heck_case_impl(cx, |str| str.to_title_case())
+}
+
+fn switch_to_snake_case(cx: &mut Context) {
+    switch_heck_case_impl(cx, |str| str.to_snake_case())
+}
+
+fn switch_to_kebab_case(cx: &mut Context) {
+    switch_heck_case_impl(cx, |str| str.to_kebab_case())
+}
+
 fn switch_to_uppercase(cx: &mut Context) {
     switch_case_impl(cx, |string| {
         string.chunks().map(|chunk| chunk.to_uppercase()).collect()

helix-term/src/keymap/default.rs

@@ -19,9 +19,16 @@ pub fn default() -> HashMap<Mode, KeyTrie> {
         "R" => replace_with_yanked,
         "A-." =>  repeat_last_motion,
 
-        "~" => switch_case,
-        "`" => switch_to_lowercase,
-        "A-`" => switch_to_uppercase,
+        "~" => switch_to_alternate_case,
+        "`" => { "Case"
+            "l" => switch_to_lowercase,
+            "u" => switch_to_uppercase,
+            "p" => switch_to_pascal_case,
+            "c" => switch_to_camel_case,
+            "t" => switch_to_title_case,
+            "s" => switch_to_snake_case,
+            "k" => switch_to_kebab_case,
+        },
 
         "home" => goto_line_start,
         "end" => goto_line_end,