feat: add ternary operator(?)

ccc.h

@@ -122,6 +122,7 @@ typedef enum {
   ND_SHR,        // >>
   ND_A_SHL,      // <<=
   ND_A_SHR,      // >>=
+  ND_TERNARY,    // ? :
 } NodeKind;
 // AST node type
 typedef struct Node Node;

codegen.c

@@ -391,6 +391,18 @@ void gen(Node *node) {
       store(node->ty);
       inc(node);
       return;
+    case ND_TERNARY:
+      int seq = labelseq++;
+      gen(node->cond);
+      printf("  pop rax\n");
+      printf("  cmp rax, 0\n");
+      printf("  je .Lelse%d\n", seq);
+      gen(node->then);
+      printf("  jmp .Lend%d\n", seq);
+      printf(".Lelse%d:\n", seq);
+      gen(node->els);
+      printf(".Lend%d:\n", seq);
+      return;
     case ND_A_ADD:
     case ND_A_SUB:
     case ND_A_MUL:

parse.c

@@ -161,6 +161,7 @@ bool is_typename();
 Node *stmt();
 Node *expr();
 Node *assign();
+Node *conditional();
 Node *bitand();
 Node * bitor ();
 Node *bitxor();
@@ -820,10 +821,10 @@ Node *expr() {
   }
   return node;
 }
-// assign = logor (assign-op assign)?
+// assign = conditional (assign-op assign)?
 // assign-op = "=" | "+=" | "-=" | "*=" | "/=" | "%=" | "<<=" | ">>="
 Node *assign() {
-  Node *node = logor();
+  Node *node = conditional();
   Token *tok;
   if (tok = consume("=")) {
     node = new_binary(ND_ASSIGN, node, assign(), tok);
@@ -852,6 +853,21 @@ Node *assign() {
   return node;
 }
 
+// conditional = logor ("?" expr ":" condtional)?
+Node *conditional() {
+  Node *node = logor();
+  Token *tok = consume("?");
+  while (!tok) {
+    return node;
+  }
+  Node *ternary = new_node(ND_TERNARY, tok);
+  ternary->cond = node;
+  ternary->then = expr();
+  expect(":");
+  ternary->els = conditional();
+  return ternary;
+}
+
 // logor = logand ("||" logand)*
 Node *logor() {
   Node *node = logand();

tests

@@ -825,6 +825,9 @@ int main() {
   assert(-1, ({ int i=-1; i; }), "int i=-1; i;");
   assert(-1, ({ int i=-1; i>>=1; i; }), "int i=1; i>>1;");
 
+  assert(2, 0?1:2, "0?1:2");
+  assert(1, 1?1:2, "0?1:2");
+
   printf("OK\n");
   return 0;
 }

tokenize.c

@@ -285,7 +285,7 @@ Token *tokenize() {
       continue;
     }
     // Single-letter punctuator
-    if (strchr("+-*/()<>;={},&[].,!~|^:", *p)) {
+    if (strchr("+-*/()<>;={},&[].,!~|^:?", *p)) {
       cur = new_token(TK_RESERVED, cur, p++, 1);
       continue;
     }

type.c

@@ -165,6 +165,9 @@ void visit(Node* node) {
     case ND_BITNOT:
       node->ty = node->lhs->ty;
       return;
+    case ND_TERNARY:
+      node->ty = node->then->ty;
+      return;
     case ND_COMMA:
       node->ty = node->lhs->ty;
       return;