[rust] add Location line/column and chop methods

rust/ruby-prism-sys/src/lib.rs

@@ -35,3 +35,25 @@ mod bindings {
 }
 
 pub use self::bindings::*;
+
+/// Line and column information for a given byte offset relative to the
+/// beginning of the source.
+#[repr(C)]
+#[derive(Debug, Clone, Copy)]
+pub struct pm_line_column_t {
+    /// The 1-indexed line number relative to the start line configured on the
+    /// parser.
+    pub line: i32,
+    /// The 0-indexed column number in bytes.
+    pub column: u32,
+}
+
+extern "C" {
+    /// Return the line and column number for the given byte offset relative to
+    /// the beginning of the source.
+    pub fn pm_newline_list_line_column(
+        list: *const pm_newline_list_t,
+        cursor: u32,
+        start_line: i32,
+    ) -> pm_line_column_t;
+}

rust/ruby-prism/src/lib.rs

@@ -14,13 +14,15 @@ mod bindings {
 }
 
 mod node;
+mod node_ext;
 mod parse_result;
 
 use std::mem::MaybeUninit;
 use std::ptr::NonNull;
 
 pub use self::bindings::*;
 pub use self::node::{ConstantId, ConstantList, ConstantListIter, Integer, NodeList, NodeListIter};
+pub use self::node_ext::ConstantPathError;
 pub use self::parse_result::{Comment, CommentType, Comments, Diagnostic, Diagnostics, Location, MagicComment, MagicComments, ParseResult};
 
 use ruby_prism_sys::{pm_parse, pm_parser_init, pm_parser_t};
@@ -160,6 +162,48 @@ mod tests {
         assert_eq!(slice, "222");
     }
 
+    #[test]
+    #[allow(clippy::similar_names)]
+    fn location_line_column_test() {
+        let source = "foo\nbar\nbaz";
+        let result = parse(source.as_ref());
+
+        let node = result.node();
+        let program = node.as_program_node().unwrap();
+        let statements = program.statements().body();
+        let mut iter = statements.iter();
+        let _foo = iter.next().unwrap();
+        let bar = iter.next().unwrap();
+        let baz = iter.next().unwrap();
+
+        let bar_loc = bar.location();
+        assert_eq!(bar_loc.start_line(), 2);
+        assert_eq!(bar_loc.end_line(), 2);
+        assert_eq!(bar_loc.start_column(), 0);
+        assert_eq!(bar_loc.end_column(), 3);
+
+        let baz_loc = baz.location();
+        assert_eq!(baz_loc.start_line(), 3);
+        assert_eq!(baz_loc.end_line(), 3);
+        assert_eq!(baz_loc.start_column(), 0);
+        assert_eq!(baz_loc.end_column(), 3);
+    }
+
+    #[test]
+    fn test_chop() {
+        let result = parse(b"foo");
+        let mut location = result.node().as_program_node().unwrap().location();
+
+        assert_eq!(location.chop().as_slice(), b"fo");
+        assert_eq!(location.chop().chop().chop().as_slice(), b"");
+
+        // Check that we don't go negative.
+        for _ in 0..10 {
+            location = location.chop();
+        }
+        assert_eq!(location.as_slice(), b"");
+    }
+
     #[test]
     fn visitor_test() {
         use super::{visit_interpolated_regular_expression_node, visit_regular_expression_node, InterpolatedRegularExpressionNode, RegularExpressionNode, Visit};