scanner: refactor keyword detection

src/scanner.c

@@ -42,12 +42,13 @@ static bool lookahead_buffer_find_char(LookaheadBuffer *buffer,
 
 // Tries to find the keyword `str` in the character stream of `lexer`.
 //
-// Since TSLexer doesn't allow backtracking and we need it to lookup different
-// keywords, we have to implement backtracking ourselves.
+// Since TSLexer doesn't allow backtracking and we need it to lookup
+// different keywords, we have to implement backtracking ourselves.
 //
 // It's relatively simple:
 // * if we have any buffered data, try it first
-// * otherwise pull from the stream while simultaneously adding to the buffer
+// * otherwise pull from the stream while simultaneously adding to the
+// buffer
 //
 // The next call will have the buffer populated.
 static bool lookahead_buffer_find_keyword(LookaheadBuffer *buffer,
@@ -155,6 +156,19 @@ static bool is_element_text_terminator_for_import_expression(int ch) {
   return false;
 }
 
+const char *statement_keywords[] = {
+    // Comments
+    "//",
+    "/*",
+    // Other statements
+    "if ",
+    "else ",
+    "for ",
+    "switch ",
+};
+const int statement_keywords_count =
+    sizeof(statement_keywords) / sizeof(const char *);
+
 static bool scan_element_text(Scanner *scanner, TSLexer *lexer) {
   lexer->result_symbol = ELEMENT_TEXT;
 
@@ -172,32 +186,17 @@ static bool scan_element_text(Scanner *scanner, TSLexer *lexer) {
     return false;
   }
 
-  // Detect if the node starts with a comment
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "//")) {
-    goto done;
-  }
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "/*")) {
-    goto done;
-  }
-
-  // 1. Detect if the node starts with a keyword that makes it a statement
-  // instead of a text element
-  //
-  // Since we're looking for a multicharacter token we need backtracking but
-  // TSLexer doesn't provide it so we have to do it ourselves.
+  // Detect if the node starts with a keyword that makes it a statement instead.
+  for (size_t i = 0; i < statement_keywords_count; i++) {
+    const char *keyword = statement_keywords[i];
 
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "if ")) {
-    goto done;
-  }
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "else ")) {
-    goto done;
-  }
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "for ")) {
-    goto done;
-  }
-  if (lookahead_buffer_find_keyword(&buffer, lexer, "switch ")) {
-    goto done;
+    // Since we're looking for a multicharacter token we need backtracking but
+    // TSLexer doesn't provide it so we have to do it ourselves.
+    if (lookahead_buffer_find_keyword(&buffer, lexer, keyword)) {
+      goto done;
+    }
   }
+
   // Try for a "@" which signals a component import expression
   if (lookahead_buffer_find_keyword(&buffer, lexer, "@")) {
     scanner->saw_at_symbol = true;
@@ -211,7 +210,8 @@ static bool scan_element_text(Scanner *scanner, TSLexer *lexer) {
     goto done;
   }
 
-  // If we saw a @ symbol, we could be in an import expression.
+  // If we saw a @ symbol, we could be in an import expression and the
+  // terminator characters differ.
   if (scanner->saw_at_symbol) {
     if (lookahead_buffer_find_char(
             &buffer, is_element_text_terminator_for_import_expression)) {