diff --git a/.gitignore b/.gitignore
index 3a7a3a8..c14a965 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 *\#*
 build
 doc/build
+vgcore.*
diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index 5c7cba0..0cad324 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -4,6 +4,9 @@ EXPR ::=
 | ASSERT
 | DECL
 | ASSIGN
+| BEGIN
+BEGIN ::= begin BLOCK end
+BLOCK ::= EXPR*
 ASSIGN ::= (ident|INDEX) assign EXPR
 DECL ::= (var|const) ident assign EXPR
 ASSERT ::= (assert_eq|assert_ne) tuple
diff --git a/lib/compiler.c b/lib/compiler.c
index b80d145..d81171f 100644
--- a/lib/compiler.c
+++ b/lib/compiler.c
@@ -32,6 +32,24 @@ void compiler_compile(compiler_t* self,
 
     switch (node->kind)
     {
+        case NODE_BLOCK: {
+
+            sym_open_scope(sym);
+            for (size_t i=0; i<node->children.size; i++)
+            {
+                compiler_compile(
+                    self, 
+                    node->children.data[i], 
+                    prog
+                );
+            }
+
+            sym_close_scope(sym);
+        } break;
+
+        case NODE_BEGIN: {
+            compiler_compile(self, node->children.data[0], prog);
+        } break;
         case NODE_ASSIGN: {
             node_t* target = node->children.data[0];
             node_t* expr = node->children.data[1];
@@ -125,8 +143,17 @@ void compiler_compile(compiler_t* self,
 
         case NODE_IDENT: {
             char const* name = node->value;
-            sym_entry_t* entry = sym_try_get_value(sym, name);
-            assert(entry);
+            sym_entry_t const* entry = sym_try_get_value(
+                sym, 
+                name
+            );
+
+            if (!entry) {
+                err_push(&self->err, node->line,
+                         "undefined '%s'", name);
+                return;
+            }
+
             prog_add_instr(prog, OP_LOCAL_LOAD, entry->local_addr);
         } break;
 
diff --git a/lib/lexer.c b/lib/lexer.c
index fc871f3..aa9e9d9 100644
--- a/lib/lexer.c
+++ b/lib/lexer.c
@@ -171,6 +171,8 @@ node_t* lexer_try_new_next(lexer_t* self)
         }
     }
 
+    CCM_KEYWORD("begin", NODE_BEGIN, 0);
+    CCM_KEYWORD("end", NODE_END, 0);
     CCM_KEYWORD("var", NODE_VAR, 0);
     CCM_KEYWORD("const", NODE_CONST, 0);
     CCM_KEYWORD("assert_eq", NODE_ASSERT_EQ, 0);
diff --git a/lib/node.h b/lib/node.h
index 47bd665..8ed2cfa 100644
--- a/lib/node.h
+++ b/lib/node.h
@@ -15,7 +15,8 @@ G(NODE_OSQUARE), G(NODE_CSQUARE), G(NODE_INDEX), \
 G(NODE_STR), G(NODE_LT), G(NODE_LE), G(NODE_GT), \
 G(NODE_GE), G(NODE_EQ), G(NODE_NE), G(NODE_ARRAY), \
 G(NODE_VAR), G(NODE_IDENT), G(NODE_ASSIGN), \
-G(NODE_VARDECL), G(NODE_CONST), G(NODE_CONSTDECL)
+G(NODE_VARDECL), G(NODE_CONST), G(NODE_CONSTDECL), \
+G(NODE_BEGIN), G(NODE_BLOCK), G(NODE_END)
 
 CCM_ENUM_H(NodeKind, NODE_KIND);
 
diff --git a/lib/parser.c b/lib/parser.c
index 833a833..96188bf 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -147,12 +147,62 @@ node_t* parser_try_new_expr(parser_t* self)
         return CCM_TRY(parser_try_new_assert);
     }
 
+    if (lexer_peek_kind(self->lexer, NODE_BEGIN, 0))
+    {
+        return CCM_TRY(parser_try_new_begin);
+    }
+
     node_t* assign = CCM_TRY(parser_try_new_assign);
     if (assign) { return assign; }
 
     return CCM_TRY(parser_try_new_or);
 }
 
+node_t* parser_try_new_begin(parser_t* self)
+{
+    assert(self);
+
+    if (!lexer_peek_kind(self->lexer, NODE_BEGIN, 0))
+    {
+        return NULL;
+    }
+
+    lexer_consume_next(self->lexer, NODE_BEGIN);
+
+    node_t* node = malloc(sizeof(node_t));
+    node_init(node, NODE_BEGIN, "", self->lexer->line);
+    
+    node_t* block = CCM_TRY(parser_try_new_block);
+    node_push_new_child(node, block);
+
+    if (!block || !lexer_peek_kind(self->lexer, NODE_END, 0))
+    {
+        node_free(node); free(node);
+        return NULL;
+    }
+
+    lexer_consume_next(self->lexer, NODE_END);
+
+    return node;
+}
+
+node_t* parser_try_new_block(parser_t* self)
+{
+    assert(self);
+    node_t* node = malloc(sizeof(node_t));
+    node_init(node, NODE_BLOCK, "", self->lexer->line);
+
+    while (1) 
+    {
+        node_t* expr = CCM_TRY(parser_try_new_expr);
+        if (!expr) { break; }
+
+        node_push_new_child(node, expr);
+    }
+    
+    return node;
+}
+
 node_t* parser_try_new_assign(parser_t* self)
 {
     assert(self);
diff --git a/lib/parser.h b/lib/parser.h
index ea13765..c5b0984 100644
--- a/lib/parser.h
+++ b/lib/parser.h
@@ -25,6 +25,8 @@ int parser_ensure(parser_t* self, node_t* node, NodeKind kind);
 
 node_t* parser_try_new_module(parser_t* self);
 node_t* parser_try_new_expr(parser_t* self);
+node_t* parser_try_new_begin(parser_t* self);
+node_t* parser_try_new_block(parser_t* self);
 node_t* parser_try_new_assign(parser_t* self);
 node_t* parser_try_new_decl(parser_t* self);
 node_t* parser_try_new_assert(parser_t* self);
diff --git a/lib/sym.c b/lib/sym.c
index 3241ee0..32323e8 100644
--- a/lib/sym.c
+++ b/lib/sym.c
@@ -15,6 +15,7 @@ void sym_free(sym_t* self)
         sym_free_env(self, self->env);
         free(self->env);
     }
+
 }
 
 void sym_free_env(sym_t* self, env_t* env)
@@ -58,8 +59,17 @@ void sym_close_scope(sym_t* self)
     assert(self);
     assert(self->env);
 
+    for (size_t i=0; i<self->env->entries.size; i++)
+    {
+        sym_entry_t* entry = self->env->entries.data[i];
+        free(entry->name);
+        free(entry);
+    }
+
     vec_free(&self->env->entries);
-    self->env = self->env->parent;
+    env_t* parent = self->env->parent;
+    free(self->env);
+    self->env = parent;
 }
 
 
@@ -72,7 +82,7 @@ int sym_declare(sym_t* self,
     assert(self->env);
     assert(name);
 
-    if (sym_try_get_value(self, name) != NULL)
+    if (sym_try_get_env_value(self,self->env, name) != NULL)
     {
         return 0;
     }
diff --git a/tests/block.ccm b/tests/block.ccm
new file mode 100644
index 0000000..c9ec1e0
--- /dev/null
+++ b/tests/block.ccm
@@ -0,0 +1,36 @@
+var a = 12
+
+begin
+    a = 32
+end
+
+assert_eq (32, a)
+
+# SHADOWING
+# =========
+
+var b = 34
+
+begin
+    var b = "bim"
+    assert_eq ("bim", b)
+end
+
+assert_eq(34, b)
+
+# NESTED BLOCKS
+# =============
+var c = "hello"
+
+begin
+    var c = "world"
+    begin
+        var c = "pizza"
+        c = "cat"
+        assert_eq ("cat", c)
+    end
+    assert_eq ("world", c)
+end
+
+assert_eq ("hello", c)
+