Fix #23: Allow empty anonymous variadic arguments.

2 files changed, 42 insertions, 9 deletions

diff --git a/src/main/java/org/anarres/cpp/Preprocessor.java b/src/main/java/org/anarres/cpp/Preprocessor.java
index f4e93cd..af3b896 100644
--- a/src/main/java/org/anarres/cpp/Preprocessor.java
+++ b/src/main/java/org/anarres/cpp/Preprocessor.java
@@ -784,15 +784,27 @@ public class Preprocessor implements Closeable {
                  * is stripped from arguments. */
 
                 if (args.size() != m.getArgs()) {
-                    error(tok,
-                            "macro " + m.getName()
-                            + " has " + m.getArgs() + " parameters "
-                            + "but given " + args.size() + " args");
-                    /* We could replay the arg tokens, but I
-                     * note that GNU cpp does exactly what we do,
-                     * i.e. output the macro name and chew the args.
-                     */
-                    return false;
+                    if (m.isVariadic()) {
+                        if (args.size() == m.getArgs() - 1) {
+                            args.add(new Argument());
+                        } else {
+                            error(tok,
+                                    "variadic macro " + m.getName()
+                                    + " has at least " + (m.getArgs() - 1) + " parameters "
+                                    + "but given " + args.size() + " args");
+                            return false;
+                        }
+                    } else {
+                        error(tok,
+                                "macro " + m.getName()
+                                + " has " + m.getArgs() + " parameters "
+                                + "but given " + args.size() + " args");
+                        /* We could replay the arg tokens, but I 
+                         * note that GNU cpp does exactly what we do,
+                         * i.e. output the macro name and chew the args.
+                         */
+                        return false;
+                    }
                 }
 
                 for (Argument a : args) {
diff --git a/src/test/java/org/anarres/cpp/PreprocessorTest.java b/src/test/java/org/anarres/cpp/PreprocessorTest.java
index 80d0cba..13bd944 100644
--- a/src/test/java/org/anarres/cpp/PreprocessorTest.java
+++ b/src/test/java/org/anarres/cpp/PreprocessorTest.java
@@ -132,6 +132,14 @@ public class PreprocessorTest {
                 I("__VA_ARGS__"), WHITESPACE, // __VA_ARGS__ is not expanded in this case.
                 I("b")
         );
+        /* Missing arguments are fine. */
+        testInput("var()\n", NL,
+                I("a"), WHITESPACE,
+                /* No expansion for 'x'. */ WHITESPACE,
+                I("__VA_ARGS__"), WHITESPACE,
+                I("b")
+        );
+
         /* Variadic macros with anonymous args. */
         testInput("#define var2(x, ...) a x __VA_ARGS__ e\n", NL);
         testInput("var2(b, c, d)\n", NL,
@@ -141,6 +149,14 @@ public class PreprocessorTest {
                 I("d"), WHITESPACE,
                 I("e")
         );
+        /* Missing arguments are fine. */
+        testInput("var2(b)\n", NL,
+                I("a"), WHITESPACE,
+                I("b"), WHITESPACE,
+                /* No expansion for '__VA_ARGS__'. */ WHITESPACE,
+                I("e")
+        );
+
         testInput("#define var3(...) a __VA_ARGS__ d\n", NL);
         testInput("var3(b, c)\n", NL,
                 I("a"), WHITESPACE,
@@ -148,6 +164,11 @@ public class PreprocessorTest {
                 I("c"), WHITESPACE,
                 I("d")
         );
+        testInput("var3()\n", NL,
+                I("a"), WHITESPACE,
+                /* No expansion for '__VA_ARGS__'. */ WHITESPACE,
+                I("d")
+        );
 
         testInput("#define _Widen(x) L ## x\n", NL);
         testInput("#define Widen(x) _Widen(x)\n", NL);