feat: `switch_to_sentence_case` (`` `S ``)

_

book/src/generated/static-cmd.md

@@ -59,6 +59,7 @@
 | `switch_to_pascal_case` | Switch to PascalCase | normal: `` `p ``, select: `` `p `` |
 | `switch_to_camel_case` | Switch to camelCase | normal: `` `c ``, select: `` `c `` |
 | `switch_to_title_case` | Switch to Title Case | normal: `` `t ``, select: `` `t `` |
+| `switch_to_sentence_case` | Switch to Sentence case | normal: `` `S ``, select: `` `S `` |
 | `switch_to_snake_case` | Switch to snake_case | normal: `` `s ``, select: `` `s `` |
 | `switch_to_kebab_case` | Switch to kebab-case | normal: `` `k ``, select: `` `k `` |
 | `page_up` | Move page up | normal: `` <C-b> ``, `` Z<C-b> ``, `` z<C-b> ``, `` <pageup> ``, `` Z<pageup> ``, `` z<pageup> ``, select: `` <C-b> ``, `` Z<C-b> ``, `` z<C-b> ``, `` <pageup> ``, `` Z<pageup> ``, `` z<pageup> ``, insert: `` <pageup> `` |

book/src/keymap.md

@@ -247,6 +247,7 @@ Various commands for changing the case of text in different ways.
 | `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 Sentence case                     | `switch_to_sentence_case`  |
 | `s`              | Switch text to snake_case                        | `switch_to_snake_case`     |
 | `k`              | Switch text to kebab-case                        | `switch_to_kebab_case`     |
 | `a`              | Switch text to aLTERNATE cASE                    | `switch_to_alternate_case` |

helix-core/src/case_conversion.rs

@@ -9,13 +9,20 @@ fn has_camel_transition(prev: Option<char>, current: char) -> bool {
     current.is_uppercase() && prev.is_some_and(|ch| ch.is_lowercase())
 }
 
-pub fn smart_case_conversion(
+#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
+enum CapitalizeWords {
+    AllButFirst,
+    All,
+    First,
+}
+
+fn smart_case_conversion(
     chars: impl Iterator<Item = char>,
     buf: &mut Tendril,
-    capitalize_first: bool,
+    capitalize: CapitalizeWords,
     separator: Option<char>,
 ) {
-    let mut should_capitalize_current = capitalize_first;
+    let mut should_capitalize_current = capitalize != CapitalizeWords::AllButFirst;
     let mut prev = None;
 
     let add_separator_if_needed = |prev: Option<char>, buf: &mut Tendril| {
@@ -30,7 +37,7 @@ pub fn smart_case_conversion(
 
     for current in chars.skip_while(|ch| ch.is_whitespace()) {
         if !current.is_alphanumeric() {
-            should_capitalize_current = true;
+            should_capitalize_current = capitalize != CapitalizeWords::First;
             add_separator_if_needed(prev, buf);
             prev = Some(current);
             continue;
@@ -38,7 +45,7 @@ pub fn smart_case_conversion(
 
         if has_camel_transition(prev, current) {
             add_separator_if_needed(prev, buf);
-            should_capitalize_current = true;
+            should_capitalize_current = capitalize != CapitalizeWords::First;
         }
 
         if should_capitalize_current {
@@ -54,7 +61,7 @@ pub fn smart_case_conversion(
     *buf = buf.trim_end().into();
 }
 
-pub fn separator_case_conversion(
+fn separator_case_conversion(
     chars: impl Iterator<Item = char>,
     buf: &mut Tendril,
     separator: char,
@@ -143,15 +150,19 @@ pub fn into_snake_case(chars: impl Iterator<Item = char>, buf: &mut Tendril) {
 }
 
 pub fn into_title_case(chars: impl Iterator<Item = char>, buf: &mut Tendril) {
-    smart_case_conversion(chars, buf, true, Some(' '));
+    smart_case_conversion(chars, buf, CapitalizeWords::All, Some(' '));
+}
+
+pub fn into_sentence_case(chars: impl Iterator<Item = char>, buf: &mut Tendril) {
+    smart_case_conversion(chars, buf, CapitalizeWords::First, Some(' '));
 }
 
 pub fn into_camel_case(chars: impl Iterator<Item = char>, buf: &mut Tendril) {
-    smart_case_conversion(chars, buf, false, None);
+    smart_case_conversion(chars, buf, CapitalizeWords::AllButFirst, None);
 }
 
 pub fn into_pascal_case(chars: impl Iterator<Item = char>, buf: &mut Tendril) {
-    smart_case_conversion(chars, buf, true, None);
+    smart_case_conversion(chars, buf, CapitalizeWords::All, None);
 }
 
 /// Create functional versions of the "into_*" case functions that take a `&mut Tendril`
@@ -176,6 +187,7 @@ to_case! {
     into_title_case => to_title_case
     into_kebab_case => to_kebab_case
     into_snake_case => to_snake_case
+    into_sentence_case => to_sentence_case
 }
 
 #[cfg(test)]
@@ -296,6 +308,7 @@ mod tests {
     fn test_title_case_conversion() {
         let tests = [
             ("hello world", "Hello World"),
+            ("hello world again", "Hello World Again"),
             ("Hello World", "Hello World"),
             ("hello_world", "Hello World"),
             ("HELLO_WORLD", "Hello World"),
@@ -315,6 +328,30 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_sentence_case_conversion() {
+        let tests = [
+            ("hello world", "Hello world"),
+            ("hello world again", "Hello world again"),
+            ("Hello World", "Hello world"),
+            ("hello_world", "Hello world"),
+            ("HELLO_WORLD", "Hello world"),
+            ("hello-world", "Hello world"),
+            ("hello  world", "Hello world"),
+            ("   hello world", "Hello world"),
+            ("hello\tworld", "Hello world"),
+            ("HELLO  WORLD", "Hello world"),
+            ("HELLO-world", "Hello world"),
+            ("hello  WORLD ", "Hello world"),
+            ("helloWorld", "Hello world"),
+        ];
+
+        for (input, expected) in tests {
+            dbg!(input);
+            assert_eq!(to_sentence_case(input.chars()), expected)
+        }
+    }
+
     #[test]
     fn test_kebab_case_conversion() {
         let tests = [

helix-term/src/commands.rs

@@ -18,11 +18,7 @@ use tui::{
 pub use typed::*;
 
 use helix_core::{
-    case_conversion::{
+    case_conversion, char_idx_at_visual_offset,
-        to_alternate_case, to_camel_case, to_kebab_case, to_lowercase, to_pascal_case,
-        to_snake_case, to_title_case, to_uppercase,
-    },
-    char_idx_at_visual_offset,
     chars::char_is_word,
     command_line, comment,
     doc_formatter::TextFormat,
@@ -361,6 +357,7 @@ impl MappableCommand {
         switch_to_pascal_case, "Switch to PascalCase",
         switch_to_camel_case, "Switch to camelCase",
         switch_to_title_case, "Switch to Title Case",
+        switch_to_sentence_case, "Switch to Sentence case",
         switch_to_snake_case, "Switch to snake_case",
         switch_to_kebab_case, "Switch to kebab-case",
         page_up, "Move page up",
@@ -1717,6 +1714,7 @@ fn replace(cx: &mut Context) {
     })
 }
 
+#[inline]
 fn switch_case_impl<F>(cx: &mut Context, change_fn: F)
 where
     F: for<'a> Fn(&mut (dyn Iterator<Item = char> + 'a)) -> Tendril,
@@ -1739,35 +1737,39 @@ where
 }
 
 fn switch_to_pascal_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_pascal_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_pascal_case(chars))
 }
 
 fn switch_to_camel_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_camel_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_camel_case(chars))
 }
 
 fn switch_to_lowercase(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_lowercase(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_lowercase(chars))
 }
 
 fn switch_to_uppercase(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_uppercase(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_uppercase(chars))
 }
 
 fn switch_to_alternate_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_alternate_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_alternate_case(chars))
 }
 
 fn switch_to_title_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_title_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_title_case(chars))
+}
+
+fn switch_to_sentence_case(cx: &mut Context) {
+    switch_case_impl(cx, |chars| case_conversion::to_sentence_case(chars))
 }
 
 fn switch_to_snake_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_snake_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_snake_case(chars))
 }
 
 fn switch_to_kebab_case(cx: &mut Context) {
-    switch_case_impl(cx, |chars| to_kebab_case(chars))
+    switch_case_impl(cx, |chars| case_conversion::to_kebab_case(chars))
 }
 
 pub fn scroll(cx: &mut Context, offset: usize, direction: Direction, sync_cursor: bool) {

helix-term/src/keymap/default.rs

@@ -27,6 +27,7 @@ pub fn default() -> HashMap<Mode, KeyTrie> {
             "p" => switch_to_pascal_case,
             "c" => switch_to_camel_case,
             "t" => switch_to_title_case,
+            "S" => switch_to_sentence_case,
             "s" => switch_to_snake_case,
             "k" => switch_to_kebab_case,
         },