Parser: Add the 'pass' keyword

--
MOS_MIGRATED_REVID=88857682

3 files changed, 15 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
index b49fb1ec52..7531b84ae3 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Lexer.java
@@ -456,6 +456,7 @@ public final class Lexer {
     keywordMap.put("in", TokenKind.IN);
     keywordMap.put("not", TokenKind.NOT);
     keywordMap.put("or", TokenKind.OR);
+    keywordMap.put("pass", TokenKind.PASS);
     keywordMap.put("return", TokenKind.RETURN);
     keywordMap.put("try", TokenKind.TRY);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
index 6a856f65e8..9805e45a9f 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/Parser.java
@@ -1016,16 +1016,27 @@ class Parser {
     parseStatement(list, true);
   }
 
+  // small_stmt | 'pass'
+  private void parseSmallStatementOrPass(List<Statement> list) {
+    if (token.kind == TokenKind.PASS) {
+      // Skip the token, don't add it to the list.
+      // It has no existence in the AST.
+      expect(TokenKind.PASS);
+    } else {
+      list.add(parseSmallStatement());
+    }
+  }
+
   // simple_stmt ::= small_stmt (';' small_stmt)* ';'? NEWLINE
   private void parseSimpleStatement(List<Statement> list) {
-    list.add(parseSmallStatement());
+    parseSmallStatementOrPass(list);
 
     while (token.kind == TokenKind.SEMI) {
       nextToken();
       if (token.kind == TokenKind.NEWLINE) {
         break;
       }
-      list.add(parseSmallStatement());
+      parseSmallStatementOrPass(list);
     }
     expect(TokenKind.NEWLINE);
     // This is a safe place to recover: There is a new line at top-level
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/TokenKind.java b/src/main/java/com/google/devtools/build/lib/syntax/TokenKind.java
index 889fa6690f..e7e92b4260 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/TokenKind.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/TokenKind.java
@@ -56,6 +56,7 @@ public enum TokenKind {
   NOT_EQUALS("!="),
   OR("or"),
   OUTDENT("outdent"),
+  PASS("pass"),
   PERCENT("%"),
   PLUS("+"),
   PLUS_EQUALS("+="),