Add recognition of multi-line field expression (tree-sitter#23)

corpus/expressions.txt

@@ -474,3 +474,39 @@ def f() = {
          (assignment_expression (identifier) (infix_expression (identifier) (operator_identifier) (identifier)))
          (enumerator (identifier) (call_expression (identifier) (arguments)) (guard (identifier))))
        (block (call_expression (identifier) (arguments (identifier) (identifier))))))))
+
+===============================
+Chained expressions
+===============================
+
+def main() {
+  val myList = List(1, 2, 3)
+
+  myList.map(_ * 2)
+
+  myList
+    .map(_ * 2)
+
+  myList
+    .length
+}
+
+---
+
+(compilation_unit
+  (function_definition
+    (identifier)
+    (parameters)
+    (block
+      (val_definition (identifier) (call_expression
+        (identifier)
+        (arguments (integer_literal) (integer_literal) (integer_literal))))
+      (call_expression
+        (field_expression (identifier) (identifier))
+        (arguments (infix_expression
+          (identifier) (operator_identifier) (integer_literal))))
+      (call_expression
+        (field_expression (identifier) (identifier))
+        (arguments (infix_expression
+          (identifier) (operator_identifier) (integer_literal))))
+      (field_expression (identifier) (identifier)))))

src/scanner.c

@@ -76,6 +76,10 @@ bool tree_sitter_scala_external_scanner_scan(void *payload, TSLexer *lexer,
   }
 
   if (valid_symbols[AUTOMATIC_SEMICOLON] && newline_count > 0) {
+    // NOTE: When there's a dot after a new line it could be a multi-line field
+    // expression, in which case we don't recognize it as an automatic semicolon.
+    if (lexer->lookahead == '.') return false;
+
     lexer->mark_end(lexer);
     lexer->result_symbol = AUTOMATIC_SEMICOLON;