feat: implement sticky-context

A lot more work has been put into this and those were 116 commits up to
this point.
I decided to squash all of them so that i will have an easier time
rebasing in the future.

book/src/editor.md

@@ -17,6 +17,7 @@
 - [`[editor.soft-wrap]` Section](#editorsoft-wrap-section)
 - [`[editor.smart-tab]` Section](#editorsmart-tab-section)
 - [`[editor.inline-diagnostics]` Section](#editorinline-diagnostics-section)
+- [`[editor.sticky-context]` Section](#editorsticky-context-section)
 
 ### `[editor]` Section
 
@@ -433,3 +434,23 @@ end-of-line-diagnostics = "hint"
 [editor.inline-diagnostics]
 cursor-line = "warning" # show warnings and errors on the cursorline inline
 ```
+
+### `[editor.sticky-context]` Section
+
+Option for sticky context, which is a feature that puts bigger blocks of code
+e.g. Functions to the top of the viewport
+
+| Key         | Description                                                                                | Default |
+| ---         | ---                                                                                        | ---     |
+| `enable`    | Display context of current line if outside the view                                        | `false` |
+| `indicator` | Display an additional line to indicate what part of the view is the sticky context         | `false` |
+| `max-lines` | The maximum number of lines to be shown as sticky context. 0 = 1/3 of the viewports height | `0`     |
+
+Example:
+
+```toml
+[editor.sticky-context]
+enable = true
+indicator = true
+max-lines = 10
+```

book/src/guides/context.md

@@ -0,0 +1,26 @@
+# Adding context queries
+
+Helix uses tree-sitter to filter out specific scopes in which said scope may exceed the current
+editor view, but which may be important for the developer to know.
+These context require an accompanying tree-sitter grammar and a `context.scm` query file
+to work properly.
+Query files should be placed in `runtime/queries/{language}/context.scm`
+when contributing to Helix. Note that to test the query files locally you should put
+them under your local runtime directory (`~/.config/helix/runtime` on Linux for example).
+
+The following [captures][tree-sitter-captures] are recognized:
+
+| Capture Name     |
+| ---              |
+| `context`        |
+| `context.params` |
+
+[Example query files][context-examples] can be found in the helix GitHub repository.
+
+## Queries for the sticky-context feature
+
+All nodes that have a scope, should be captured with `context`, as an example a basic class.
+The `context.params` is a capture for all the function parameters. 
+
+[tree-sitter-captures]: https://tree-sitter.github.io/tree-sitter/using-parsers#capturing-nodes
+[context-examples]: https://github.com/search?q=repo%3Ahelix-editor%2Fhelix+filename%3Acontext.scm&type=Code&ref=advsearch&l=&l=

helix-core/src/syntax.rs

@@ -155,6 +155,10 @@ pub struct LanguageConfiguration {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub debugger: Option<DebugAdapterConfig>,
 
+    /// The Grammar query for Sticky Context
+    #[serde(skip)]
+    pub(crate) context_query: OnceCell<Option<ContextQuery>>,
+
     /// Automatic insertion of pairs to parentheses, brackets,
     /// etc. Defaults to true. Optionally, this can be a list of 2-tuples
     /// to specify a list of characters to pair. This overrides the
@@ -609,6 +613,11 @@ pub struct TextObjectQuery {
     pub query: Query,
 }
 
+#[derive(Debug)]
+pub struct ContextQuery {
+    pub query: Query,
+}
+
 #[derive(Debug)]
 pub enum CapturedNode<'a> {
     Single(Node<'a>),
@@ -804,6 +813,15 @@ impl LanguageConfiguration {
             .as_ref()
     }
 
+    pub fn context_query(&self) -> Option<&ContextQuery> {
+        self.context_query
+            .get_or_init(|| {
+                self.load_query("context.scm")
+                    .map(|query| ContextQuery { query })
+            })
+            .as_ref()
+    }
+
     pub fn scope(&self) -> &str {
         &self.scope
     }

helix-term/src/health.rs

@@ -12,18 +12,25 @@ pub enum TsFeature {
     Highlight,
     TextObject,
     AutoIndent,
+    Context,
 }
 
 impl TsFeature {
     pub fn all() -> &'static [Self] {
-        &[Self::Highlight, Self::TextObject, Self::AutoIndent]
+        &[
+            Self::Highlight,
+            Self::TextObject,
+            Self::AutoIndent,
+            Self::Context,
+        ]
     }
 
     pub fn runtime_filename(&self) -> &'static str {
         match *self {
             Self::Highlight => "highlights.scm",
             Self::TextObject => "textobjects.scm",
             Self::AutoIndent => "indents.scm",
+            Self::Context => "context.scm",
         }
     }
 
@@ -32,6 +39,7 @@ impl TsFeature {
             Self::Highlight => "Syntax Highlighting",
             Self::TextObject => "Treesitter Textobjects",
             Self::AutoIndent => "Auto Indent",
+            Self::Context => "Sticky Context",
         }
     }
 
@@ -40,6 +48,7 @@ impl TsFeature {
             Self::Highlight => "Highlight",
             Self::TextObject => "Textobject",
             Self::AutoIndent => "Indent",
+            Self::Context => "Context",
         }
     }
 }