Introduce the LSH compiler

Cargo.toml

@@ -28,5 +28,6 @@ lto = "thin"                # Similarly, speed up linking by a ton
 
 [workspace.dependencies]
 edit = { path = "./crates/edit" }
+lsh = { path = "./crates/lsh" }
 stdext = { path = "./crates/stdext" }
 unicode-gen = { path = "./crates/unicode-gen" }

assets/highlighting-tests/COMMIT_EDITMSG

@@ -0,0 +1,62 @@
+lsh: flip legacy flag, add follow-up hook & diff test
+
+Refactors placeholder logic and introduces a lightweight follow-up hook.
+Adds diff highlighting test and removes outdated asset to streamline visuals.
+
+# Please enter the commit message for your changes. Lines starting
+# with '#' will be ignored, and an empty message aborts the commit.
+#
+# On branch foobar
+# Your branch is up to date with 'origin/foobar'.
+#
+# Changes to be committed:
+#	renamed:    foo.rs -> bar.rs
+#	modified:   src/lsh/definitions.rs
+#	deleted:    assets/old_logo.svg
+#	new file:   baz.rs
+#
+# ------------------------ >8 ------------------------
+# Do not modify or remove the line above.
+# Everything below it will be ignored.
+diff --git a/src/lsh/definitions.rs b/src/lsh/definitions.rs
+index a1b2c3d..d4c3b2a 100644
+--- a/src/lsh/definitions.rs
++++ b/src/lsh/definitions.rs
+@@ -12,9 +12,11 @@ // context line 12
+ // context line 13
+-// old placeholder logic A
+-const LEGACY_FLAG: bool = true;
+-// end legacy block
++// updated placeholder logic A
++const LEGACY_FLAG: bool = false; // flipped for test
++// added note: migration in progress
++// end legacy block
+ // context line 19
+ // context line 20
+@@ -42,7 +44,12 @@ // context line 42
+ // context line 43
+-    do_placeholder_action(alpha, beta);
++    // Split actions for clarity
++    do_placeholder_prepare(alpha);
++    do_placeholder_action(alpha, beta);
++    if (enable_extra()) {
++        do_placeholder_followup(beta);
++    }
+ // context line 50
+ // context line 51
+ // context line 52
+@@ -90,6 +97,15 @@ // context line 90
+ // context line 91
+ // context line 92
++/// Added lightweight fake helper
++fn enable_extra() -> bool {
++    // Pretend this consults a config value
++    true
++}
++
++// Temporary debug instrumentation (to be removed)
++const _DEBUG_HOOK: &str = "lsh:extra";
++
+ // context line 93
+ // context line 94
+ // context line 95

assets/highlighting-tests/diff.diff

@@ -0,0 +1,142 @@
+diff --git a/src/lsh/definitions.rs b/src/lsh/definitions.rs
+index a1b2c3d..d4c3b2a 100644
+--- a/src/lsh/definitions.rs
++++ b/src/lsh/definitions.rs
+@@ -12,9 +12,11 @@ // context line 12
+ // context line 13
+-// old placeholder logic A
+-const LEGACY_FLAG: bool = true;
+-// end legacy block
++// updated placeholder logic A
++const LEGACY_FLAG: bool = false; // flipped for test
++// added note: migration in progress
++// end legacy block
+ // context line 19
+ // context line 20
+@@ -42,7 +44,12 @@ // context line 42
+ // context line 43
+-    do_placeholder_action(alpha, beta);
++    // Split actions for clarity
++    do_placeholder_prepare(alpha);
++    do_placeholder_action(alpha, beta);
++    if (enable_extra()) {
++        do_placeholder_followup(beta);
++    }
+ // context line 50
+ // context line 51
+ // context line 52
+@@ -90,6 +97,15 @@ // context line 90
+ // context line 91
+ // context line 92
++/// Added lightweight fake helper
++fn enable_extra() -> bool {
++    // Pretend this consults a config value
++    true
++}
++
++// Temporary debug instrumentation (to be removed)
++const _DEBUG_HOOK: &str = "lsh:extra";
++
+ // context line 93
+ // context line 94
+ // context line 95
+
+diff --git a/src/tui.rs b/src/tui.rs
+index 1122334..5566778 100644
+--- a/src/tui.rs
++++ b/src/tui.rs
+@@ -5,8 +5,13 @@ // context line 5
+ // context line 6
+ // context line 7
+-// previous rendering stub
+-render_placeholder(frame);
++// refined rendering sequence
++begin_frame(frame);
++render_header(frame);
++render_body(frame);
++render_footer(frame);
++end_frame(frame);
++
+ // context line 14
+ // context line 15
+ // context line 16
+
+diff --git a/README.md b/README.md
+index 9aa9aa9..1bb1bb1 100644
+--- a/README.md
++++ b/README.md
+@@ -1,6 +1,11 @@
+ # Project Title
+-Some brief description here.
++Some brief description here (updated).
++
++Experimental notes:
++- Added fake diff example
++- Demonstrates multi-hunk & multi-file patch
++
+ ## Usage
+ Run the binary as needed.
+
+diff --git a/Cargo.toml b/Cargo.toml
+index cafe123..fade321 100644
+--- a/Cargo.toml
++++ b/Cargo.toml
+@@ -8,7 +8,10 @@ edition = "2021"
+ # context
+ [features]
+-default = []
++default = ["experimental-preview"]
++experimental-preview = []
++
++# NOTE: Above feature is placeholder & fake
+
+ [dependencies]
+ # context
+@@ -20,6 +23,7 @@ anyhow = "1"
+ # context
+ # instrumentation (fake addition)
+ tracing = "0.1"
++tracing-subscriber = "0.3"
+
+diff --git a/src/feature/experimental.rs b/src/feature/experimental.rs
+new file mode 100644
+index 0000000..abc1234
+--- /dev/null
++++ b/src/feature/experimental.rs
+@@ -0,0 +1,24 @@
++//! Placeholder experimental module (fake content).
++//! This file exists only to demonstrate a multi-file diff.
++#![allow(dead_code)]
++
++pub struct ExperimentalToggle {
++    enabled: bool,
++}
++
++impl ExperimentalToggle {
++    pub fn new() -> Self {
++        Self { enabled: true }
++    }
++    pub fn enabled(&self) -> bool {
++        self.enabled
++    }
++}
++
++pub fn run_experimental_path() {
++    if ExperimentalToggle::new().enabled() {
++        // Fake behavior
++        eprintln!("(fake) running experimental path");
++    }
++}
++
+
+diff --git a/assets/old_logo.svg b/assets/old_logo.svg
+deleted file mode 100644
+index 55aa55a..0000000
+--- a/assets/old_logo.svg
++++ /dev/null
+@@ -1,5 +0,0 @@
+-<!-- Fake removed asset -->
+-<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 10 10">
+-  <rect width="10" height="10" fill="#FF00FF"/>
+-  <text x="1" y="9" font-size="3">X</text>
+-</svg>

assets/highlighting-tests/git-rebase-todo

@@ -0,0 +1,54 @@
+pick 3f9d2ab # chore(ci): add initial pipeline
+pick e12c0ff # feat(io): introduce streaming reader
+reword 7ac14d0 feat(io): add zero-copy buffered writer
+edit 4d92b67 fix(io): handle partial UTF-8 sequences at buffer boundary
+pick 8bb3a21 docs: expand README performance section
+squash 1c02f55 docs: tidy wording in performance section
+pick 54ae91b feat(cli): add --color=auto detection
+fixup 0b77c3e feat(cli): typo in help text
+fixup -c 2f4e8ab feat(cli): adjust arg parsing error message
+pick 6d8e5f1 refactor(core): split large module into submodules
+break
+pick a41e9d3 test(core): add regression tests for issue #410
+exec cargo test --package edit --lib --quiet
+pick c3bb921 perf(render): SIMD accelerate line diffing
+drop 91d0f2e debug(render): temporary logging (to be dropped)
+label pre-merge-split
+pick d2f7ac4 feat(ui): add mouse wheel smooth scrolling
+pick f1a4bd9 feat(ui): add high-DPI awareness
+label post-ui
+update-ref refs/heads/feature/ui-stack-post
+reset pre-merge-split
+merge -C 5ab77e3 post-ui # Merge UI feature stack
+pick d8c4b91 build: bump version to 0.9.0
+
+# Rebase 3f9d2ab..d8c4b91 onto d8c4b91 (18 commands)
+#
+# Commands:
+# p, pick <commit> = use commit
+# r, reword <commit> = use commit, but edit the commit message
+# e, edit <commit> = use commit, but stop for amending
+# s, squash <commit> = use commit, but meld into previous commit
+# f, fixup [-C | -c] <commit> = like "squash" but keep only the previous
+#                    commit's log message, unless -C is used, in which case
+#                    keep only this commit's message; -c is same as -C but
+#                    opens the editor
+# x, exec <command> = run command (the rest of the line) using shell
+# b, break = stop here (continue rebase later with 'git rebase --continue')
+# d, drop <commit> = remove commit
+# l, label <label> = label current HEAD with a name
+# t, reset <label> = reset HEAD to a label
+# m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
+#         create a merge commit using the original merge commit's
+#         message (or the oneline, if no original merge commit was
+#         specified); use -c <commit> to reword the commit message
+# u, update-ref <ref> = track a placeholder for the <ref> to be updated
+#                       to this position in the new commits. The <ref> is
+#                       updated at the end of the rebase
+#
+# These lines can be re-ordered; they are executed from top to bottom.
+#
+# If you remove a line here THAT COMMIT WILL BE LOST.
+#
+# However, if you remove everything, the rebase will be aborted.
+#

crates/edit/src/buffer/mod.rs

@@ -2501,7 +2501,7 @@ impl TextBuffer {
     }
 
     /// Extracts the contents of the current selection the user made.
-    /// This differs from [`TextBuffer::extract_selection()`] in that
+    /// This differs from `TextBuffer::extract_selection()` in that
     /// it does nothing if the selection was made by searching.
     pub fn extract_user_selection(&mut self, delete: bool) -> Option<Vec<u8>> {
         if !self.has_selection() {