? expression

lexer.c

@@ -10,7 +10,8 @@ enum opcode {
     STRING,
     AND,
     STAR,
-    PLUS
+    PLUS,
+    QMARK
 };
 struct Exploration
 {
@@ -96,6 +97,12 @@ Node *mkPlus(Node *child)
     return node;
 }
 
+Node *mkQmark(Node *child)
+{
+    Node *node= mkNode(QMARK);
+    node->children[0]= child;
+    return node;
+}
 
 int execute(Node *node, Exploration *in)
 {
@@ -146,6 +153,11 @@ int execute(Node *node, Exploration *in)
           }
          
       }
+        case QMARK: {
+            // 0 ou 1
+            if(execute(node->children[0], in)==1) return execute(node->children[0], in);
+            return 1;
+        }
     }
     printf("this cannot happen\n");
     abort();
@@ -154,7 +166,7 @@ int execute(Node *node, Exploration *in)
 
 int main(int argc, char **argv)
 {
-    Exploration *in= mkExploration("aabbcc");
+    Exploration *in= mkExploration("acc");
 
     /*Node *program=
 	mkString("aabbcc");
@@ -175,8 +187,8 @@ int main(int argc, char **argv)
                 mkStar(mkString("c")))));
 */
     Node *program= 
-            mkAnd(mkPlus(mkString("a")),       // "a"*"b"*"c"*
-                mkAnd(mkPlus(mkString("b")),
+            mkAnd(mkQmark(mkString("a")),       // "a"*"b"*"c"*
+                mkAnd(mkQmark(mkString("b")),
                 mkPlus(mkString("c"))));
 
     if (execute(program, in)<=0)