address comments on rope library

Cargo.lock

@@ -2309,7 +2309,7 @@ checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 [[package]]
 name = "steel-core"
 version = "0.6.0"
-source = "git+https://github.com/mattwparas/steel.git#1fb88e561474c723a4fd2675553d6091a380aef1"
+source = "git+https://github.com/mattwparas/steel.git#01e42f435de3f6ca8cf083fdfc422d2a445d5bc9"
 dependencies = [
  "abi_stable",
  "anyhow",
@@ -2345,7 +2345,7 @@ dependencies = [
 [[package]]
 name = "steel-derive"
 version = "0.5.0"
-source = "git+https://github.com/mattwparas/steel.git#1fb88e561474c723a4fd2675553d6091a380aef1"
+source = "git+https://github.com/mattwparas/steel.git#01e42f435de3f6ca8cf083fdfc422d2a445d5bc9"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2355,7 +2355,7 @@ dependencies = [
 [[package]]
 name = "steel-gen"
 version = "0.2.0"
-source = "git+https://github.com/mattwparas/steel.git#1fb88e561474c723a4fd2675553d6091a380aef1"
+source = "git+https://github.com/mattwparas/steel.git#01e42f435de3f6ca8cf083fdfc422d2a445d5bc9"
 dependencies = [
  "codegen",
  "serde",
@@ -2365,7 +2365,7 @@ dependencies = [
 [[package]]
 name = "steel-parser"
 version = "0.6.0"
-source = "git+https://github.com/mattwparas/steel.git#1fb88e561474c723a4fd2675553d6091a380aef1"
+source = "git+https://github.com/mattwparas/steel.git#01e42f435de3f6ca8cf083fdfc422d2a445d5bc9"
 dependencies = [
  "fxhash",
  "lasso",

helix-core/src/extensions.rs

@@ -5,10 +5,13 @@ pub mod steel_implementations {
 
     use smallvec::SmallVec;
     use steel::{
-        rvals::{Custom, SteelString},
+        rvals::{as_underlying_type, Custom, SteelString},
         steel_vm::{builtin::BuiltInModule, register_fn::RegisterFn},
+        SteelVal,
     };
 
+    use helix_stdx::rope::RopeSliceExt;
+
     use crate::syntax::{AutoPairConfig, SoftWrap};
 
     impl steel::rvals::Custom for crate::Position {}
@@ -16,20 +19,38 @@ pub mod steel_implementations {
     impl steel::rvals::Custom for AutoPairConfig {}
     impl steel::rvals::Custom for SoftWrap {}
 
-    #[derive(Clone, Copy, Debug)]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq)]
     enum SliceKind {
         Normal(usize, usize),
         Byte(usize, usize),
         Line(usize),
     }
 
-    #[derive(Clone)]
+    #[derive(Clone, PartialEq, Eq)]
     pub struct SteelRopeSlice {
         text: crate::Rope,
         ranges: SmallVec<[SliceKind; 5]>,
     }
 
-    impl Custom for SteelRopeSlice {}
+    impl Custom for SteelRopeSlice {
+        // `equal?` on two ropes should return true if they are the same
+        fn equality_hint(&self, other: &dyn steel::rvals::CustomType) -> bool {
+            if let Some(other) = as_underlying_type::<SteelRopeSlice>(other) {
+                self == other
+            } else {
+                false
+            }
+        }
+
+        fn equality_hint_general(&self, other: &steel::SteelVal) -> bool {
+            match other {
+                SteelVal::StringV(s) => self.to_slice() == s.as_str(),
+                SteelVal::Custom(c) => Self::equality_hint(&self, c.borrow().as_ref()),
+
+                _ => false,
+            }
+        }
+    }
 
     impl SteelRopeSlice {
         pub fn from_string(string: SteelString) -> Self {
@@ -95,30 +116,48 @@ pub mod steel_implementations {
             self.to_slice().len_lines()
         }
 
+        pub fn trim_start(mut self) -> Self {
+            for (idx, c) in self.to_slice().chars().enumerate() {
+                if !c.is_whitespace() {
+                    self.ranges.push(SliceKind::Normal(0, idx));
+                    break;
+                }
+            }
+
+            self
+        }
+
         pub fn trimmed_starts_with(&self, pat: SteelString) -> bool {
             let maybe_owned = Cow::from(self.to_slice());
 
             maybe_owned.trim_start().starts_with(pat.as_str())
         }
+
+        pub fn starts_with(&self, pat: SteelString) -> bool {
+            self.to_slice().starts_with(pat.as_str())
+        }
+
+        pub fn ends_with(&self, pat: SteelString) -> bool {
+            self.to_slice().ends_with(pat.as_str())
+        }
     }
 
     pub fn rope_module() -> BuiltInModule {
         let mut module = BuiltInModule::new("helix/core/text");
 
         module
-            .register_fn("string->slice", SteelRopeSlice::from_string)
-            .register_fn("slice->slice", SteelRopeSlice::slice)
-            .register_fn("slice-char->byte", SteelRopeSlice::char_to_byte)
-            .register_fn("slice->byte-slice", SteelRopeSlice::byte_slice)
-            .register_fn("slice->line", SteelRopeSlice::line)
-            .register_fn("slice->string", SteelRopeSlice::to_string)
-            .register_fn("slice-len-chars", SteelRopeSlice::len_chars)
-            .register_fn("slice-char-ref", SteelRopeSlice::get_char)
-            .register_fn("slice-len-lines", SteelRopeSlice::len_lines)
-            .register_fn(
-                "slice-trim-and-starts-with?",
-                SteelRopeSlice::trimmed_starts_with,
-            );
+            .register_fn("string->rope", SteelRopeSlice::from_string)
+            .register_fn("rope->slice", SteelRopeSlice::slice)
+            .register_fn("rope-char->byte", SteelRopeSlice::char_to_byte)
+            .register_fn("rope->byte-slice", SteelRopeSlice::byte_slice)
+            .register_fn("rope->line", SteelRopeSlice::line)
+            .register_fn("rope->string", SteelRopeSlice::to_string)
+            .register_fn("rope-len-chars", SteelRopeSlice::len_chars)
+            .register_fn("rope-char-ref", SteelRopeSlice::get_char)
+            .register_fn("rope-len-lines", SteelRopeSlice::len_lines)
+            .register_fn("rope-starts-with?", SteelRopeSlice::starts_with)
+            .register_fn("rope-ends-with?", SteelRopeSlice::ends_with)
+            .register_fn("rope-trim-start", SteelRopeSlice::trim_start);
 
         module
     }