chore: deprecate C++ scanners

tree-sitter · Feb 14, 2024 · 4efaaa3 · 4efaaa3
1 parent d80d101
commit 4efaaa3
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Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/cli/loader/src/lib.rs b/cli/loader/src/lib.rs
@@ -524,7 +524,12 @@ impl Loader {
                 command.arg("/O2");
             }
             command.arg(parser_path);
+
             if let Some(scanner_path) = scanner_path.as_ref() {
+                if scanner_path.extension() != Some("c".as_ref()) {
+                    eprintln!("Warning: Using a C++ scanner is now deprecated. Please migrate your scanner code to C, as C++ support will be removed in the near future.");
+                }
+
                 command.arg(scanner_path);
             }
             command
@@ -560,6 +565,7 @@ impl Loader {
                 if scanner_path.extension() == Some("c".as_ref()) {
                     command.arg("-xc").arg("-std=c99").arg(scanner_path);
                 } else {
+                    eprintln!("Warning: Using a C++ scanner is now deprecated. Please migrate your scanner code to C, as C++ support will be removed in the near future.");
                     command.arg(scanner_path);
                 }
             }
@@ -750,6 +756,7 @@ impl Loader {
                 .and_then(|ext| ext.to_str())
                 .map_or(false, |ext| ["cc", "cpp"].contains(&ext))
             {
+                eprintln!("Warning: Using a C++ scanner is now deprecated. Please migrate your scanner code to C, as C++ support will be removed in the near future.");
                 command.arg("-xc++");
             }
             command.arg(scanner_filename);

diff --git a/docs/section-3-creating-parsers.md b/docs/section-3-creating-parsers.md
@@ -649,7 +649,11 @@ grammar({
 Then, add another C or C++ source file to your project. Currently, its path must be `src/scanner.c` or `src/scanner.cc` for the CLI to recognize it. Be sure to add this file to the `sources` section of your `binding.gyp` file so that it will be included when your project is compiled by Node.js and uncomment the appropriate block in your `bindings/rust/build.rs` file so that it will be included in your Rust crate.
 
 > **Note**
-> While it is possible to write an external scanner in C++, it can be difficult to get working cross-platform and introduces extra requirements; therefore it is *greatly* preferred to use C.
+>
+> C++ scanners are now deprecated and will be unsupported in the near future.
+> While it is currently possible to write an external scanner in C++, it can be difficult
+> to get working cross-platform and introduces extra requirements; therefore it
+> is *greatly* preferred to use C.
 
 In this new source file, define an [`enum`][enum] type containing the names of all of your external tokens. The ordering of this enum must match the order in your grammar's `externals` array; the actual names do not matter.