Add treesitter textobjects (#728)

* Add treesitter textobject queries

Only for Go, Python and Rust for now.

* Add tree-sitter textobjects

Only has functions and class objects as of now.

* Fix tests

* Add docs for tree-sitter textobjects

* Add guide for creating new textobject queries

* Add parameter textobject

Only parameter.inside is implemented now, parameter.around
will probably require custom predicates akin to nvim' `make-range`
since we want to select a trailing comma too (a comma will be
an anonymous node and matching against them doesn't work similar
to named nodes)

* Simplify TextObject cell init

1 files changed, 19 insertions, 0 deletions

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 9f54292d..272a9d9a 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -4465,9 +4465,28 @@ fn select_textobject(cx: &mut Context, objtype: textobject::TextObject) {
             let (view, doc) = current!(cx.editor);
             let text = doc.text().slice(..);
 
+            let textobject_treesitter = |obj_name: &str, range: Range| -> Range {
+                let (lang_config, syntax) = match doc.language_config().zip(doc.syntax()) {
+                    Some(t) => t,
+                    None => return range,
+                };
+                textobject::textobject_treesitter(
+                    text,
+                    range,
+                    objtype,
+                    obj_name,
+                    syntax.tree().root_node(),
+                    lang_config,
+                    count,
+                )
+            };
+
             let selection = doc.selection(view.id).clone().transform(|range| {
                 match ch {
                     'w' => textobject::textobject_word(text, range, objtype, count),
+                    'c' => textobject_treesitter("class", range),
+                    'f' => textobject_treesitter("function", range),
+                    'p' => textobject_treesitter("parameter", range),
                     // TODO: cancel new ranges if inconsistent surround matches across lines
                     ch if !ch.is_ascii_alphanumeric() => {
                         textobject::textobject_surround(text, range, objtype, ch, count)