Revert "refactor: use C for the external scanner (#13)" (#15)

This reverts commit 24ed4fd565.

binding.gyp

@@ -9,7 +9,7 @@
       "sources": [
         "bindings/node/binding.cc",
         "src/parser.c",
-		"src/scanner.c",
+        # If your language uses an external scanner, add it here.
       ],
       "cflags_c": [
         "-std=c99",

bindings/rust/build.rs

@@ -2,7 +2,7 @@ fn main() {
     let src_dir = std::path::Path::new("src");
 
     let mut c_config = cc::Build::new();
-    c_config.include(src_dir);
+    c_config.include(&src_dir);
     c_config
         .flag_if_supported("-Wno-unused-parameter")
         .flag_if_supported("-Wno-unused-but-set-variable")
@@ -10,10 +10,29 @@ fn main() {
     let parser_path = src_dir.join("parser.c");
     c_config.file(&parser_path);
 
+    // If your language uses an external scanner written in C,
+    // then include this block of code:
+
+    /*
     let scanner_path = src_dir.join("scanner.c");
     c_config.file(&scanner_path);
     println!("cargo:rerun-if-changed={}", scanner_path.to_str().unwrap());
+    */
 
     c_config.compile("parser");
     println!("cargo:rerun-if-changed={}", parser_path.to_str().unwrap());
+
+    // If your language uses an external scanner written in C++,
+    // then include this block of code:
+
+    let mut cpp_config = cc::Build::new();
+    cpp_config.cpp(true);
+    cpp_config.include(&src_dir);
+    cpp_config
+        .flag_if_supported("-Wno-unused-parameter")
+        .flag_if_supported("-Wno-unused-but-set-variable");
+    let scanner_path = src_dir.join("scanner.cc");
+    cpp_config.file(&scanner_path);
+    cpp_config.compile("scanner");
+    println!("cargo:rerun-if-changed={}", scanner_path.to_str().unwrap());
 }

src/scanner.cc

@@ -1,11 +1,12 @@
+#include <cwctype>
 #include <tree_sitter/parser.h>
-#include <wctype.h>
 
+namespace {
 enum TokenType { BRACKET_ARGUMENT, BRACKET_COMMENT, LINE_COMMENT };
 void skip(TSLexer *lexer) { lexer->advance(lexer, true); }
 void advance(TSLexer *lexer) { lexer->advance(lexer, false); }
 void skip_wspace(TSLexer *lexer) {
-  while (iswspace(lexer->lookahead)) {
+  while (std::iswspace(lexer->lookahead)) {
     skip(lexer);
   }
 }
@@ -71,6 +72,8 @@ bool scan(void *payload, TSLexer *lexer, bool const *valid_symbols) {
   return false;
 }
 
+} // namespace
+extern "C" {
 void *tree_sitter_cmake_external_scanner_create() { return NULL; }
 void tree_sitter_cmake_external_scanner_destroy(void *payload) {}
 unsigned tree_sitter_cmake_external_scanner_serialize(void *payload,
@@ -84,3 +87,4 @@ bool tree_sitter_cmake_external_scanner_scan(void *payload, TSLexer *lexer,
                                              bool const *valid_symbols) {
   return scan(payload, lexer, valid_symbols);
 }
+}