Skylark: Unified ListComprehension and DictComprehension.
As a result, complex dict comprehensions (nested + with conditions) can be used.
--
MOS_MIGRATED_REVID=103374493
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 078efce..fb95228 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
@@ -767,32 +767,27 @@
// comprehension_suffix ::= 'FOR' loop_variables 'IN' expr comprehension_suffix
// | 'IF' expr comprehension_suffix
// | ']'
- private Expression parseComprehensionSuffix(ListComprehension listComprehension) {
+ private Expression parseComprehensionSuffix(
+ AbstractComprehension comprehension, TokenKind closingBracket) {
while (true) {
- switch (token.kind) {
- case FOR:
- nextToken();
- Expression loopVar = parseForLoopVariables();
- expect(TokenKind.IN);
- // The expression cannot be a ternary expression ('x if y else z') due to
- // conflicts in Python grammar ('if' is used by the comprehension).
- Expression listExpression = parseNonTupleExpression(0);
- listComprehension.addFor(loopVar, listExpression);
- break;
-
- case IF:
- nextToken();
- listComprehension.addIf(parseExpression());
- break;
-
- case RBRACKET:
- nextToken();
- return listComprehension;
-
- default:
- syntaxError(token, "expected ']', 'for' or 'if'");
- syncPast(LIST_TERMINATOR_SET);
- return makeErrorExpression(token.left, token.right);
+ if (token.kind == TokenKind.FOR) {
+ nextToken();
+ Expression loopVar = parseForLoopVariables();
+ expect(TokenKind.IN);
+ // The expression cannot be a ternary expression ('x if y else z') due to
+ // conflicts in Python grammar ('if' is used by the comprehension).
+ Expression listExpression = parseNonTupleExpression(0);
+ comprehension.addFor(loopVar, listExpression);
+ } else if (token.kind == TokenKind.IF) {
+ nextToken();
+ comprehension.addIf(parseExpression());
+ } else if (token.kind == closingBracket) {
+ nextToken();
+ return comprehension;
+ } else {
+ syntaxError(token, "expected '" + closingBracket.getPrettyName() + "', 'for' or 'if'");
+ syncPast(LIST_TERMINATOR_SET);
+ return makeErrorExpression(token.left, token.right);
}
}
}
@@ -820,10 +815,12 @@
nextToken();
return literal;
}
- case FOR: { // list comprehension
- Expression result = parseComprehensionSuffix(new ListComprehension(expression));
- return setLocation(result, start, token.right);
- }
+ case FOR:
+ { // list comprehension
+ Expression result =
+ parseComprehensionSuffix(new ListComprehension(expression), TokenKind.RBRACKET);
+ return setLocation(result, start, token.right);
+ }
case COMMA: {
List<Expression> list = parseExprList();
Preconditions.checkState(!list.contains(null),
@@ -861,17 +858,10 @@
}
DictionaryEntryLiteral entry = parseDictEntry();
if (token.kind == TokenKind.FOR) {
- // TODO(bazel-team): Reuse parseComprehensionSuffix when dict
- // comprehension is compatible with list comprehension.
-
// Dict comprehension
- nextToken();
- Expression loopVar = parseForLoopVariables();
- expect(TokenKind.IN);
- Expression listExpression = parseExpression();
- expect(TokenKind.RBRACE);
- return setLocation(new DictComprehension(
- entry.getKey(), entry.getValue(), loopVar, listExpression), start, token.right);
+ Expression result = parseComprehensionSuffix(
+ new DictComprehension(entry.getKey(), entry.getValue()), TokenKind.RBRACE);
+ return setLocation(result, start, token.right);
}
List<DictionaryEntryLiteral> entries = new ArrayList<>();
entries.add(entry);
