From f582c8b7bddc7842b87b37a272ca16814da3e229 Mon Sep 17 00:00:00 2001
From: Nik Revenco <pm@nikrev.com>
Date: Sun, 15 Jun 2025 17:42:58 +0100
Subject: [PATCH] feat: add API for selection and ranges (#33)

* feat: add API for selection and ranges

* fix: use `no_context!` macro for declaring these functions

* chore: rename accessors to structs
---
 helix-core/src/selection.rs             |  3 ++
 helix-term/src/commands/engine/steel.rs | 48 +++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/helix-core/src/selection.rs b/helix-core/src/selection.rs
index 5bde08e31..e66a87008 100644
--- a/helix-core/src/selection.rs
+++ b/helix-core/src/selection.rs
@@ -16,6 +16,7 @@ use helix_stdx::range::is_subset;
 use helix_stdx::rope::{self, RopeSliceExt};
 use smallvec::{smallvec, SmallVec};
 use std::{borrow::Cow, iter, slice};
+use steel::rvals::Custom;
 
 /// A single selection range.
 ///
@@ -62,6 +63,8 @@ pub struct Range {
     pub old_visual_position: Option<(u32, u32)>,
 }
 
+impl Custom for Range {}
+
 impl Range {
     pub fn new(anchor: usize, head: usize) -> Self {
         Self {
diff --git a/helix-term/src/commands/engine/steel.rs b/helix-term/src/commands/engine/steel.rs
index 209fa0899..8fe725d63 100644
--- a/helix-term/src/commands/engine/steel.rs
+++ b/helix-term/src/commands/engine/steel.rs
@@ -487,6 +487,54 @@ fn load_static_commands(engine: &mut Engine, generate_sources: bool) {
         }
     };
 
+    macro_rules! no_context {
+        ($name:expr, $function:expr, $doc:expr) => {{
+            module.register_fn($name, $function);
+            template_function_no_context($name, $doc);
+        }};
+    }
+
+    no_context!(
+        "selection->primary-index",
+        |sel: Selection| sel.primary_index(),
+        "Returns index of the primary selection"
+    );
+    no_context!(
+        "selection->primary-range",
+        |sel: Selection| sel.primary(),
+        "Returns the range for primary selection"
+    );
+    no_context!(
+        "selection->ranges",
+        |sel: Selection| sel.ranges().to_vec(),
+        "Returns all ranges of the selection"
+    );
+    no_context!(
+        "range-anchor",
+        |range: Range| range.anchor,
+        "Get the anchor of the range: the side that doesn't move when extending."
+    );
+    no_context!(
+        "range->from",
+        |range: Range| range.from(),
+        "Get the start of the range"
+    );
+    no_context!(
+        "range-head",
+        |range: Range| range.head,
+        "Get the head of the range, moved when extending."
+    );
+    no_context!(
+        "range->to",
+        |range: Range| range.to(),
+        "Get the end of the range"
+    );
+    no_context!(
+        "range->span",
+        |range: Range| (range.from(), range.to()),
+        "Get the span of the range (from, to)"
+    );
+
     module.register_fn("get-helix-scm-path", get_helix_scm_path);
     module.register_fn("get-init-scm-path", get_init_scm_path);