Handle conditionals in preprocessor statements.

2 files changed, 16 insertions, 3 deletions

diff --git a/src/main/java/org/anarres/cpp/Preprocessor.java b/src/main/java/org/anarres/cpp/Preprocessor.java
index 0d14b53..192ac45 100644
--- a/src/main/java/org/anarres/cpp/Preprocessor.java
+++ b/src/main/java/org/anarres/cpp/Preprocessor.java
@@ -1514,7 +1514,7 @@ public class Preprocessor implements Closeable {
                 tok = expr_token();
                 if (tok.getType() != ')') {
                     expr_untoken(tok);
-                    error(tok, "missing ) in expression");
+                    error(tok, "Missing ) in expression. Got " + tok.getText());
                     return 0;
                 }
                 break;
@@ -1628,8 +1628,17 @@ public class Preprocessor implements Closeable {
                     lhs = (lhs != 0) || (rhs != 0) ? 1 : 0;
                     break;
 
-                case '?':
-                /* XXX Handle this? */
+                case '?': {
+                    tok = expr_token();
+                    if (tok.getType() != ':') {
+                        expr_untoken(tok);
+                        error(tok, "Missing : in conditional expression. Got " + tok.getText());
+                        return 0;
+                    }
+                    long falseResult = expr(0);
+                    lhs = (lhs != 0) ? rhs : falseResult;
+                }
+                break;
 
                 default:
                     error(op,
diff --git a/src/test/java/org/anarres/cpp/PreprocessorTest.java b/src/test/java/org/anarres/cpp/PreprocessorTest.java
index 8a40823..84e7e31 100644
--- a/src/test/java/org/anarres/cpp/PreprocessorTest.java
+++ b/src/test/java/org/anarres/cpp/PreprocessorTest.java
@@ -153,6 +153,10 @@ public class PreprocessorTest {
         testInput("LStr(x);\n", NL, I("L"), "x", ';');
 
         testInput("'foo'\n", NL, SQSTRING);
+        testInput("#if 1 ? 2 : 0\nTEXT\n#endif\n", NL, NL, I("TEXT"), NL);
+        testInput("#if 1 ? 0 : 2\nTEXT\n#endif\n", NL, NL, NL);
+        testInput("#if 0 ? 0 : 2\nTEXT\n#endif\n", NL, NL, I("TEXT"), NL);
+        testInput("#if 0 ? 2 : 0\nTEXT\n#endif\n", NL, NL, NL);
 
         writer.close();