Merge pull request #130 from tree-sitter/pub-excerpt

Make `Excerpt` type public

CHANGELOG.md

···
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v0.9.2 -- 2023-04-14
+
+### Library
+
+#### Added
+
+- The `parse_error::Excerpt` type, which is used to show source excerpts, is now public.
+
 ## v0.9.1 -- 2023-04-03
 
 ### CLI

Cargo.toml

···
 [package]
 name = "tree-sitter-graph"
-version = "0.9.1"
+version = "0.9.2"
 description = "Construct graphs from parsed source code"
 homepage = "https://github.com/tree-sitter/tree-sitter-graph/"
 repository = "https://github.com/tree-sitter/tree-sitter-graph/"

src/parse_error.rs

···
 //-----------------------------------------------------------------------------
 
 /// Excerpts of source from either the target language file or the tsg rules file.
-pub(crate) struct Excerpt<'a> {
+pub struct Excerpt<'a> {
     path: &'a Path,
     source: Option<&'a str>,
     row: usize,
···
         path: &'a Path,
         source: &'a str,
         row: usize,
-        columns: Range<usize>,
+        mut columns: Range<usize>,
         indent: usize,
     ) -> Excerpt<'a> {
+        let source = source.lines().nth(row);
+        columns.end = std::cmp::min(columns.end, source.map(|s| s.len()).unwrap_or_default());
         Excerpt {
             path,
-            source: source.lines().nth(row),
+            source,
             row,
             columns,
             indent,
···
             f,
             "{}{}:{}:{}:",
             " ".repeat(self.indent),
-            white_bold(&self.path.to_str().unwrap_or("<unknown file>")),
+            white_bold(&self.path.to_string_lossy()),
             white_bold(&format!("{}", self.row + 1)),
             white_bold(&format!("{}", self.columns.start + 1)),
         )?;