Allow parentheses in initializers to be omitted

parse.c

@@ -666,8 +666,8 @@ static int count_array_init_elements(Token *tok, Type *ty) {
   return i;
 }
 
-// array-initializer = "{" initializer ("," initializer)* "}"
-static void array_initializer(Token **rest, Token *tok, Initializer *init) {
+// array-initializer1 = "{" initializer ("," initializer)* "}"
+static void array_initializer1(Token **rest, Token *tok, Initializer *init) {
   tok = skip(tok, "{");
 
   if (init->is_flexible) {
@@ -686,8 +686,23 @@ static void array_initializer(Token **rest, Token *tok, Initializer *init) {
   }
 }
 
-// struct-initializer = "{" initializer ("," initializer)* "}"
-static void struct_initializer(Token **rest, Token *tok, Initializer *init) {
+// array-initializer2 = initializer ("," initializer)*
+static void array_initializer2(Token **rest, Token *tok, Initializer *init) {
+  if (init->is_flexible) {
+    int len = count_array_init_elements(tok, init->ty);
+    *init = *new_initializer(array_of(init->ty->base, len), false);
+  }
+
+  for (int i = 0; i < init->ty->array_len && !equal(tok, "}"); i++) {
+    if (i > 0)
+      tok = skip(tok, ",");
+    initializer2(&tok, tok, init->children[i]);
+  }
+  *rest = tok;
+}
+
+// struct-initializer1 = "{" initializer ("," initializer)* "}"
+static void struct_initializer1(Token **rest, Token *tok, Initializer *init) {
   tok = skip(tok, "{");
 
   Member *mem = init->ty->members;
@@ -705,12 +720,28 @@ static void struct_initializer(Token **rest, Token *tok, Initializer *init) {
   }
 }
 
+// struct-initializer2 = initializer ("," initializer)*
+static void struct_initializer2(Token **rest, Token *tok, Initializer *init) {
+  bool first = true;
+
+  for (Member *mem = init->ty->members; mem && !equal(tok, "}"); mem = mem->next) {
+    if (!first)
+      tok = skip(tok, ",");
+    first = false;
+    initializer2(&tok, tok, init->children[mem->idx]);
+  }
+  *rest = tok;
+}
+
 static void union_initializer(Token **rest, Token *tok, Initializer *init) {
   // Unlike structs, union initializers take only one initializer,
   // and that initializes the first union member.
-  tok = skip(tok, "{");
-  initializer2(&tok, tok, init->children[0]);
-  *rest = skip(tok, "}");
+  if (equal(tok, "{")) {
+    initializer2(&tok, tok->next, init->children[0]);
+    *rest = skip(tok, "}");
+  } else {
+    initializer2(rest, tok, init->children[0]);
+  }
 }
 
 // initializer = string-initializer | array-initializer
@@ -723,24 +754,30 @@ static void initializer2(Token **rest, Token *tok, Initializer *init) {
   }
 
   if (init->ty->kind == TY_ARRAY) {
-    array_initializer(rest, tok, init);
+    if (equal(tok, "{"))
+      array_initializer1(rest, tok, init);
+    else
+      array_initializer2(rest, tok, init);
     return;
   }
 
   if (init->ty->kind == TY_STRUCT) {
+    if (equal(tok, "{")) {
+      struct_initializer1(rest, tok, init);
+      return;
+    }
+
     // A struct can be initialized with another struct. E.g.
     // `struct T x = y;` where y is a variable of type `struct T`.
     // Handle that case first.
-    if (!equal(tok, "{")) {
-      Node *expr = assign(rest, tok);
-      add_type(expr);
-      if (expr->ty->kind == TY_STRUCT) {
-        init->expr = expr;
-        return;
-      }
+    Node *expr = assign(rest, tok);
+    add_type(expr);
+    if (expr->ty->kind == TY_STRUCT) {
+      init->expr = expr;
+      return;
     }
 
-    struct_initializer(rest, tok, init);
+    struct_initializer2(rest, tok, init);
     return;
   }
 

test/initializer.c

@@ -7,7 +7,7 @@ long g6 = 6;
 int g9[3] = {0, 1, 2};
 struct {char a; int b;} g11[2] = {{1, 2}, {3, 4}};
 struct {int a[2];} g12[2] = {{{1, 2}}};
-union { int a; char b[8]; } g13[2] = {{0x01020304}, {0x05060708}};
+union { int a; char b[8]; } g13[2] = {0x01020304, 0x05060708};
 char g17[] = "foobar";
 char g18[10] = "foobar";
 char g19[3] = "foobar";
@@ -23,6 +23,9 @@ int *g28 = &g11[1].a;
 long g29 = (long)(long)g26;
 struct { struct { int a[3]; } a; } g30 = {{{1,2,3}}};
 int *g31=g30.a.a;
+struct {int a[2];} g40[2] = {{1, 2}, 3, 4};
+struct {int a[2];} g41[2] = {1, 2, 3, 4};
+char g43[][4] = {'f', 'o', 'o', 0, 'b', 'a', 'r', 0};
 
 int main() {
   ASSERT(1, ({ int x[3]={1,2,3}; x[0]; }));
@@ -136,6 +139,25 @@ int main() {
   ASSERT(2, g31[1]);
   ASSERT(3, g31[2]);
 
+  ASSERT(1, g40[0].a[0]);
+  ASSERT(2, g40[0].a[1]);
+  ASSERT(3, g40[1].a[0]);
+  ASSERT(4, g40[1].a[1]);
+
+  ASSERT(1, g41[0].a[0]);
+  ASSERT(2, g41[0].a[1]);
+  ASSERT(3, g41[1].a[0]);
+  ASSERT(4, g41[1].a[1]);
+
+  ASSERT(0, ({ int x[2][3]={0,1,2,3,4,5}; x[0][0]; }));
+  ASSERT(3, ({ int x[2][3]={0,1,2,3,4,5}; x[1][0]; }));
+
+  ASSERT(0, ({ struct {int a; int b;} x[2]={0,1,2,3}; x[0].a; }));
+  ASSERT(2, ({ struct {int a; int b;} x[2]={0,1,2,3}; x[1].a; }));
+
+  ASSERT(0, strcmp(g43[0], "foo"));
+  ASSERT(0, strcmp(g43[1], "bar"));
+
   printf("OK\n");
   return 0;
 }