Add ?: operator

chibi.h

@@ -100,6 +100,7 @@ typedef enum {
   ND_LT,         // <
   ND_LE,         // <=
   ND_ASSIGN,     // =
+  ND_TERNARY,    // ?:
   ND_PRE_INC,    // pre ++
   ND_PRE_DEC,    // pre --
   ND_POST_INC,   // post ++

codegen.c

@@ -226,6 +226,19 @@ static void gen(Node *node) {
     gen(node->rhs);
     store(node->ty);
     return;
+  case ND_TERNARY: {
+    int seq = labelseq++;
+    gen(node->cond);
+    printf("  pop rax\n");
+    printf("  cmp rax, 0\n");
+    printf("  je  .L.else.%d\n", seq);
+    gen(node->then);
+    printf("  jmp .L.end.%d\n", seq);
+    printf(".L.else.%d:\n", seq);
+    gen(node->els);
+    printf(".L.end.%d:\n", seq);
+    return;
+  }
   case ND_PRE_INC:
     gen_lval(node->lhs);
     printf("  push [rsp]\n");

parse.c

@@ -186,6 +186,7 @@ static Node *stmt(void);
 static Node *stmt2(void);
 static Node *expr(void);
 static Node *assign(void);
+static Node *conditional(void);
 static Node *logor(void);
 static Node *logand(void);
 static Node *bitand(void);
@@ -883,10 +884,10 @@ static Node *expr(void) {
   return node;
 }
 
-// assign    = logor (assign-op assign)?
+// assign    = conditional (assign-op assign)?
 // assign-op = "=" | "+=" | "-=" | "*=" | "/=" | "<<=" | ">>="
 static Node *assign(void) {
-  Node *node = logor();
+  Node *node = conditional();
   Token *tok;
 
   if (tok = consume("="))
@@ -923,6 +924,21 @@ static Node *assign(void) {
   return node;
 }
 
+// conditional = logor ("?" expr ":" conditional)?
+static Node *conditional(void) {
+  Node *node = logor();
+  Token *tok = consume("?");
+  if (!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)*
 static Node *logor(void) {
   Node *node = logand();

tests

@@ -468,6 +468,9 @@ 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;
 }

type.c

@@ -113,6 +113,9 @@ void add_type(Node *node) {
   case ND_VAR:
     node->ty = node->var->ty;
     return;
+  case ND_TERNARY:
+    node->ty = node->then->ty;
+    return;
   case ND_COMMA:
     node->ty = node->rhs->ty;
     return;