Merge pull request #5 from helix-editor/lsp

LSP: mk1

8 files changed, 78 insertions, 142 deletions

diff --git a/helix-core/src/diagnostic.rs b/helix-core/src/diagnostic.rs
new file mode 100644
index 00000000..96ed6746
--- /dev/null
+++ b/helix-core/src/diagnostic.rs
@@ -0,0 +1,7 @@
+use crate::Range;
+
+pub struct Diagnostic {
+    pub range: (usize, usize),
+    pub line: usize,
+    pub message: String,
+}
diff --git a/helix-core/src/history.rs b/helix-core/src/history.rs
index e6d9a738..66445525 100644
--- a/helix-core/src/history.rs
+++ b/helix-core/src/history.rs
@@ -57,37 +57,31 @@ impl History {
         self.cursor == 0
     }
 
-    pub fn undo(&mut self, state: &mut State) {
+    // TODO: I'd like to pass Transaction by reference but it fights with the borrowck
+
+    pub fn undo(&mut self) -> Option<Transaction> {
         if self.at_root() {
             // We're at the root of undo, nothing to do.
-            return;
+            return None;
         }
 
         let current_revision = &self.revisions[self.cursor];
 
-        // TODO: pass the return value through? It should always succeed
-        let success = current_revision.revert.apply(state);
-
-        if !success {
-            panic!("Failed to apply undo!");
-        }
-
         self.cursor = current_revision.parent;
+
+        Some(current_revision.revert.clone())
     }
 
-    pub fn redo(&mut self, state: &mut State) {
+    pub fn redo(&mut self) -> Option<Transaction> {
         let current_revision = &self.revisions[self.cursor];
 
         // for now, simply pick the latest child (linear undo / redo)
         if let Some((index, transaction)) = current_revision.children.last() {
-            let success = transaction.apply(state);
-
-            if !success {
-                panic!("Failed to apply redo!");
-            }
-
             self.cursor = *index;
+
+            return Some(transaction.clone());
         }
+        None
     }
 }
 
@@ -120,17 +114,27 @@ mod test {
         assert_eq!("hello 世界!", state.doc());
 
         // ---
+        fn undo(history: &mut History, state: &mut State) {
+            if let Some(transaction) = history.undo() {
+                transaction.apply(state);
+            }
+        }
+        fn redo(history: &mut History, state: &mut State) {
+            if let Some(transaction) = history.redo() {
+                transaction.apply(state);
+            }
+        }
 
-        history.undo(&mut state);
+        undo(&mut history, &mut state);
         assert_eq!("hello world!", state.doc());
-        history.redo(&mut state);
+        redo(&mut history, &mut state);
         assert_eq!("hello 世界!", state.doc());
-        history.undo(&mut state);
-        history.undo(&mut state);
+        undo(&mut history, &mut state);
+        undo(&mut history, &mut state);
         assert_eq!("hello", state.doc());
 
         // undo at root is a no-op
-        history.undo(&mut state);
+        undo(&mut history, &mut state);
         assert_eq!("hello", state.doc());
     }
 }
diff --git a/helix-core/src/indent.rs b/helix-core/src/indent.rs
index 2e1a095e..6b9a1ab1 100644
--- a/helix-core/src/indent.rs
+++ b/helix-core/src/indent.rs
@@ -111,17 +111,17 @@ fn find_first_non_whitespace_char(state: &State, line_num: usize) -> usize {
     start
 }
 
-fn suggested_indent_for_line(state: &State, line_num: usize) -> usize {
+fn suggested_indent_for_line(syntax: Option<&Syntax>, state: &State, line_num: usize) -> usize {
     let line = state.doc.line(line_num);
     let current = indent_level_for_line(line);
 
     let start = find_first_non_whitespace_char(state, line_num);
 
-    suggested_indent_for_pos(state, start)
+    suggested_indent_for_pos(syntax, state, start)
 }
 
-pub fn suggested_indent_for_pos(state: &State, pos: usize) -> usize {
-    if let Some(syntax) = &state.syntax {
+pub fn suggested_indent_for_pos(syntax: Option<&Syntax>, state: &State, pos: usize) -> usize {
+    if let Some(syntax) = syntax {
         let byte_start = state.doc.char_to_byte(pos);
         let node = get_highest_syntax_node_at_bytepos(syntax, byte_start);
 
@@ -163,13 +163,18 @@ mod test {
 ",
         );
 
-        let mut state = State::new(doc);
-        state.set_language("source.rust", &[]);
-
-        assert_eq!(suggested_indent_for_line(&state, 0), 0); // mod
-        assert_eq!(suggested_indent_for_line(&state, 1), 1); // fn
-        assert_eq!(suggested_indent_for_line(&state, 2), 2); // 1 + 1
-        assert_eq!(suggested_indent_for_line(&state, 4), 1); // }
-        assert_eq!(suggested_indent_for_line(&state, 5), 0); // }
+        let state = State::new(doc);
+        // TODO: set_language
+        let language_config = crate::syntax::LOADER
+            .language_config_for_scope("source.rust")
+            .unwrap();
+        let highlight_config = language_config.highlight_config(&[]).unwrap().unwrap();
+        let syntax = Syntax::new(&state.doc, highlight_config.clone());
+
+        assert_eq!(suggested_indent_for_line(Some(&syntax), &state, 0), 0); // mod
+        assert_eq!(suggested_indent_for_line(Some(&syntax), &state, 1), 1); // fn
+        assert_eq!(suggested_indent_for_line(Some(&syntax), &state, 2), 2); // 1 + 1
+        assert_eq!(suggested_indent_for_line(Some(&syntax), &state, 4), 1); // }
+        assert_eq!(suggested_indent_for_line(Some(&syntax), &state, 5), 0); // }
     }
 }
diff --git a/helix-core/src/lib.rs b/helix-core/src/lib.rs
index 62d23a10..ddf1439c 100644
--- a/helix-core/src/lib.rs
+++ b/helix-core/src/lib.rs
@@ -1,4 +1,5 @@
 #![allow(unused)]
+mod diagnostic;
 pub mod graphemes;
 mod history;
 pub mod indent;
@@ -22,7 +23,8 @@ pub use selection::Range;
 pub use selection::Selection;
 pub use syntax::Syntax;
 
+pub use diagnostic::Diagnostic;
 pub use history::History;
 pub use state::State;
 
-pub use transaction::{Assoc, Change, ChangeSet, Transaction};
+pub use transaction::{Assoc, Change, ChangeSet, Operation, Transaction};
diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 13c820f1..9413fead 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -179,6 +179,11 @@ impl Selection {
         }
     }
 
+    /// Constructs a selection holding a single cursor.
+    pub fn point(pos: usize) -> Self {
+        Self::single(pos, pos)
+    }
+
     #[must_use]
     pub fn new(ranges: SmallVec<[Range; 1]>, primary_index: usize) -> Self {
         fn normalize(mut ranges: SmallVec<[Range; 1]>, mut primary_index: usize) -> Selection {
diff --git a/helix-core/src/state.rs b/helix-core/src/state.rs
index 1b0a67ae..4d531aa0 100644
--- a/helix-core/src/state.rs
+++ b/helix-core/src/state.rs
@@ -1,33 +1,14 @@
 use crate::graphemes::{nth_next_grapheme_boundary, nth_prev_grapheme_boundary, RopeGraphemes};
 use crate::syntax::LOADER;
-use crate::{ChangeSet, Position, Range, Rope, RopeSlice, Selection, Syntax};
+use crate::{ChangeSet, Diagnostic, Position, Range, Rope, RopeSlice, Selection, Syntax};
 use anyhow::Error;
 
-use std::path::PathBuf;
-
-#[derive(Copy, Clone, PartialEq, Eq, Hash)]
-pub enum Mode {
-    Normal,
-    Insert,
-    Goto,
-}
-
 /// A state represents the current editor state of a single buffer.
+#[derive(Clone)]
 pub struct State {
     // TODO: fields should be private but we need to refactor commands.rs first
-    /// Path to file on disk.
-    pub path: Option<PathBuf>,
     pub doc: Rope,
     pub selection: Selection,
-    pub mode: Mode,
-
-    pub restore_cursor: bool,
-
-    //
-    pub syntax: Option<Syntax>,
-    /// Pending changes since last history commit.
-    pub changes: ChangeSet,
-    pub old_state: Option<(Rope, Selection)>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -46,57 +27,12 @@ pub enum Granularity {
 impl State {
     #[must_use]
     pub fn new(doc: Rope) -> Self {
-        let changes = ChangeSet::new(&doc);
-        let old_state = Some((doc.clone(), Selection::single(0, 0)));
-
         Self {
-            path: None,
             doc,
             selection: Selection::single(0, 0),
-            mode: Mode::Normal,
-            restore_cursor: false,
-            syntax: None,
-            changes,
-            old_state,
         }
     }
 
-    // TODO: passing scopes here is awkward
-    pub fn load(path: PathBuf, scopes: &[String]) -> Result<Self, Error> {
-        use std::{env, fs::File, io::BufReader, path::PathBuf};
-        let _current_dir = env::current_dir()?;
-
-        let doc = Rope::from_reader(BufReader::new(File::open(path.clone())?))?;
-
-        // TODO: create if not found
-
-        let mut state = Self::new(doc);
-
-        if let Some(language_config) = LOADER.language_config_for_file_name(path.as_path()) {
-            let highlight_config = language_config.highlight_config(scopes).unwrap().unwrap();
-            // TODO: config.configure(scopes) is now delayed, is that ok?
-
-            let syntax = Syntax::new(&state.doc, highlight_config.clone());
-
-            state.syntax = Some(syntax);
-        };
-
-        state.path = Some(path);
-
-        Ok(state)
-    }
-
-    pub fn set_language(&mut self, scope: &str, scopes: &[String]) {
-        if let Some(language_config) = LOADER.language_config_for_scope(scope) {
-            let highlight_config = language_config.highlight_config(scopes).unwrap().unwrap();
-            // TODO: config.configure(scopes) is now delayed, is that ok?
-
-            let syntax = Syntax::new(&self.doc, highlight_config.clone());
-
-            self.syntax = Some(syntax);
-        };
-    }
-
     // TODO: doc/selection accessors
 
     // TODO: be able to take either Rope or RopeSlice
@@ -110,16 +46,6 @@ impl State {
         &self.selection
     }
 
-    #[inline]
-    pub fn mode(&self) -> Mode {
-        self.mode
-    }
-
-    #[inline]
-    pub fn path(&self) -> Option<&PathBuf> {
-        self.path.as_ref()
-    }
-
     // pub fn doc<R>(&self, range: R) -> RopeSlice
     // where
     //     R: std::ops::RangeBounds<usize>,
diff --git a/helix-core/src/syntax.rs b/helix-core/src/syntax.rs
index 02903637..70d42c47 100644
--- a/helix-core/src/syntax.rs
+++ b/helix-core/src/syntax.rs
@@ -62,11 +62,15 @@ impl LanguageConfiguration {
             })
             .map(Option::as_ref)
     }
+
+    pub fn scope(&self) -> &str {
+        &self.scope
+    }
 }
 
 use once_cell::sync::Lazy;
 
-pub(crate) static LOADER: Lazy<Loader> = Lazy::new(Loader::init);
+pub static LOADER: Lazy<Loader> = Lazy::new(Loader::init);
 
 pub struct Loader {
     // highlight_names ?
diff --git a/helix-core/src/transaction.rs b/helix-core/src/transaction.rs
index 6f3956aa..f1cb2ca1 100644
--- a/helix-core/src/transaction.rs
+++ b/helix-core/src/transaction.rs
@@ -5,8 +5,9 @@ use std::convert::TryFrom;
 /// (from, to, replacement)
 pub type Change = (usize, usize, Option<Tendril>);
 
+// TODO: pub(crate)
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) enum Operation {
+pub enum Operation {
     /// Move cursor by n characters.
     Retain(usize),
     /// Delete n characters.
@@ -40,6 +41,12 @@ impl ChangeSet {
     }
 
     // TODO: from iter
+    //
+
+    #[doc(hidden)] // used by lsp to convert to LSP changes
+    pub fn changes(&self) -> &[Operation] {
+        &self.changes
+    }
 
     #[must_use]
     fn len_after(&self) -> usize {
@@ -351,22 +358,6 @@ pub struct Transaction {
     // scroll_into_view
 }
 
-/// Like std::mem::replace() except it allows the replacement value to be mapped from the
-/// original value.
-pub fn take_with<T, F>(mut_ref: &mut T, closure: F)
-where
-    F: FnOnce(T) -> T,
-{
-    use std::{panic, ptr};
-
-    unsafe {
-        let old_t = ptr::read(mut_ref);
-        let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| closure(old_t)))
-            .unwrap_or_else(|_| ::std::process::abort());
-        ptr::write(mut_ref, new_t);
-    }
-}
-
 impl Transaction {
     /// Create a new, empty transaction.
     pub fn new(state: &mut State) -> Self {
@@ -376,29 +367,21 @@ impl Transaction {
         }
     }
 
+    pub fn changes(&self) -> &ChangeSet {
+        &self.changes
+    }
+
     /// Returns true if applied successfully.
     pub fn apply(&self, state: &mut State) -> bool {
         if !self.changes.is_empty() {
-            // TODO: also avoid mapping the selection if not necessary
-
-            let old_doc = state.doc().clone();
-
             // apply changes to the document
             if !self.changes.apply(&mut state.doc) {
                 return false;
             }
-
-            // Compose this transaction with the previous one
-            take_with(&mut state.changes, |changes| {
-                changes.compose(self.changes.clone()).unwrap()
-            });
-
-            if let Some(syntax) = &mut state.syntax {
-                // TODO: no unwrap
-                syntax.update(&old_doc, &state.doc, &self.changes).unwrap();
-            }
         }
 
+        // TODO: also avoid mapping the selection if not necessary
+
         // update the selection: either take the selection specified in the transaction, or map the
         // current selection through changes.
         state.selection = self