varによる変数の宣言を実装

eval.c

@@ -120,6 +120,15 @@ pVal *eval(Node *node, Env *env) {
                 put(global_env, node->name->str, pv);
                 return pv;
             }
+        case ND_VARS:
+            {
+               node = node->body->next;
+               while (node != NULL) {
+                   put(global_env, node->str, pInt(0));
+                   node = node->next;
+               }
+               return pInt(0);
+            }
         case ND_FNCALL:
             {
                 Env *fn_env = new_env(global_env);

parse.c

@@ -97,7 +97,16 @@ static Node *block() {
 }
 
 static Node *var_decl() {
-    return NULL;
+    if (!eq(read(), "var")) exit(1);
+    Node *head = new_node(ND_VARS);
+    head->body = new_node(ND_NULL);
+    Node *node = head->body->next = new_ident(read());
+    while (eq(peek(), ",")) {
+        read();
+        node = node->next = new_ident(read());
+    }
+    if (!eq(read(), ";")) exit(1);
+    return head;
 }
 static Node *const_decl() {
     return NULL;

pl0.h

@@ -53,6 +53,7 @@ typedef enum {
     ND_WRITELN,// writeln
     ND_ASSG,  // assignment
     ND_BEGIN, // begin ... end
+    ND_VARS,  // var
     ND_FNDEF, // function
     ND_ARGS,  // args
     ND_PARAMS,// parameters

test.sh

@@ -44,5 +44,6 @@ end;
 return gcd(13*4, 13*9).'
 assert 20 'function a(x) return x; function b(x) return 2*a(x); return b(10).'
 assert "123"$'\n'"0" 'begin write 123; writeln; end.'
+assert 32 'var hoge; begin hoge:=32; return hoge; end.'
 
 echo OK!