diff --git a/conf/cf-lex.l b/conf/cf-lex.l
index 04a6c994..9d5890ed 100644
--- a/conf/cf-lex.l
+++ b/conf/cf-lex.l
@@ -54,6 +54,7 @@
 struct keyword {
   byte *name;
   int value;
+  enum keyword_scope scope;
 };
 
 #include "conf/keywords.h"
@@ -718,16 +719,17 @@ cf_lex_init(int is_cli, struct config *c)
   {
     global_root_scope_pool = rp_new(&root_pool, "Keywords pool");
     linpool *kwlp = lp_new(global_root_scope_pool);
-    global_root_scope = lp_allocz(kwlp, sizeof(*global_root_scope));
+    global_root_scope = lp_allocz(kwlp, sizeof(*global_root_scope) * CFK__MAX);
 
     for (const struct keyword *k = keyword_list; k->name; k++)
     {
-      struct symbol *sym = cf_new_symbol(global_root_scope, global_root_scope_pool, kwlp, k->name);
+      struct symbol *sym = cf_new_symbol(&global_root_scope[k->scope], global_root_scope_pool, kwlp, k->name);
       sym->class = SYM_KEYWORD;
       sym->keyword = k;
     }
 
-    global_root_scope->readonly = 1;
+    for (int s = 0; s < CFK__MAX; s++)
+      global_root_scope[s].readonly = 1;
   }
 
   ifs_head = ifs = push_ifs(NULL);
@@ -751,7 +753,7 @@ cf_lex_init(int is_cli, struct config *c)
   if (is_cli)
     c->current_scope->next = config->root_scope;
   else
-    c->current_scope->next = global_root_scope;
+    c->current_scope->next = &global_root_scope[CFK_KEYWORDS];
 }
 
 /**
diff --git a/conf/conf.h b/conf/conf.h
index 8558fcba..f91d7039 100644
--- a/conf/conf.h
+++ b/conf/conf.h
@@ -143,6 +143,12 @@ struct sym_scope {
   byte readonly:1;			/* Do not add new symbols */
 };
 
+enum keyword_scope {
+  CFK_KEYWORDS,
+  CFK_METHODS,
+  CFK__MAX
+};
+
 extern struct sym_scope *global_root_scope;
 
 struct bytestring {
diff --git a/conf/confbase.Y b/conf/confbase.Y
index fbc6df62..a6f038fe 100644
--- a/conf/confbase.Y
+++ b/conf/confbase.Y
@@ -129,7 +129,7 @@ CF_DECLS
 
 %start config
 
-CF_KEYWORDS(DEFINE, ON, OFF, YES, NO, S, MS, US, PORT, VPN, MPLS, FROM)
+CF_KEYWORDS(DEFINE, ON, OFF, YES, NO, S, MS, US, PORT, VPN, MPLS, FROM, MAX, AS)
 
 CF_GRAMMAR
 
diff --git a/conf/gen_keywords.m4 b/conf/gen_keywords.m4
index a1be5847..0d7c5d4d 100644
--- a/conf/gen_keywords.m4
+++ b/conf/gen_keywords.m4
@@ -23,10 +23,12 @@ m4_define(CF_DECLS, `m4_divert(-1)')
 m4_define(CF_DEFINES, `m4_divert(-1)')
 
 # Keywords are translated to C initializers
-m4_define(CF_handle_kw, `m4_divert(1){ "m4_translit($1,[[A-Z]],[[a-z]])", $1 },
+m4_define(CF_handle_kw, `m4_divert(1){ "m4_translit($1,[[A-Z]],[[a-z]])", $1, CF_keywd_target },
 m4_divert(-1)')
-m4_define(CF_keywd, `m4_ifdef([[CF_tok_$1]],,[[m4_define([[CF_tok_$1]],1)CF_handle_kw($1)]])')
-m4_define(CF_KEYWORDS, `CF_iterate([[CF_keywd]], [[$@]])DNL')
+m4_define(CF_keywd, `m4_ifdef([[CF_tok_]]CF_keywd_target[[_$1]],,[[m4_define([[CF_tok_]]CF_keywd_target[[_$1]],1)CF_handle_kw($1)]])')
+m4_define(CF_KEYWORDS, `m4_define([[CF_keywd_target]],CFK_KEYWORDS)CF_iterate([[CF_keywd]], [[$@]])DNL')
+m4_define(CF_METHODS, `m4_define([[CF_keywd_target]],CFK_METHODS)CF_iterate([[CF_keywd]], [[$@]])DNL')
+
 
 # CLI commands generate keywords as well
 m4_define(CF_CLI, `CF_KEYWORDS(m4_translit($1, [[ ]], [[,]]))
diff --git a/conf/gen_parser.m4 b/conf/gen_parser.m4
index c4791218..993320c4 100644
--- a/conf/gen_parser.m4
+++ b/conf/gen_parser.m4
@@ -33,6 +33,8 @@ m4_define(CF_iterate, `m4_define([[CF_iter]], m4_defn([[$1]]))CF_itera($2)')
 m4_define(CF_keywd, `m4_ifdef([[CF_tok_$1]],,[[m4_define([[CF_tok_$1]],1)m4_define([[CF_toks]],CF_toks $1)]])')
 m4_define(CF_KEYWORDS, `m4_define([[CF_toks]],[[]])CF_iterate([[CF_keywd]], [[$@]])m4_ifelse(CF_toks,,,%token<s>[[]]CF_toks
 )DNL')
+m4_define(CF_METHODS, `m4_define([[CF_toks]],[[]])CF_iterate([[CF_keywd]], [[$@]])m4_ifelse(CF_toks,,,%token<s>[[]]CF_toks
+)DNL')
 
 # CLI commands
 m4_define(CF_CLI, `m4_define([[CF_cmd]], cmd_[[]]m4_translit($1, [[ ]], _))DNL
diff --git a/filter/config.Y b/filter/config.Y
index bf2aa469..a4acd729 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -21,6 +21,7 @@ static inline u32 pair_b(u32 p) { return p & 0xFFFF; }
 
 static struct f_method_scope {
   struct f_inst *object;
+  struct sym_scope scope;
 } f_method_scope_stack[32];
 static int f_method_scope_pos = -1;
 
@@ -32,12 +33,24 @@ static inline void f_push_method_scope(struct f_inst *object)
     cf_error("Too many nested method calls");
   FM = (struct f_method_scope) {
     .object = object,
+    .scope = {
+      .next = new_config->current_scope,
+      .hash = global_root_scope[CFK_METHODS].hash,
+      .active = 1,
+      .block = 1,
+      .readonly = 1,
+    },
   };
+  new_config->current_scope = &FM.scope;
 }
 
 static inline void f_pop_method_scope(void)
 {
   ASSERT_DIE(f_method_scope_pos >= 0);
+
+  ASSERT_DIE(&FM.scope == new_config->current_scope);
+  new_config->current_scope = FM.scope.next;
+
   f_method_scope_pos--;
 }
 
@@ -330,25 +343,25 @@ CF_DECLS
 
 CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
 	ACCEPT, REJECT, ERROR,
-	INT, BOOL, IP, TYPE, PREFIX, RD, PAIR, QUAD, EC, LC,
+	INT, BOOL, IP, PREFIX, RD, PAIR, QUAD, EC, LC,
 	SET, STRING, BGPMASK, BGPPATH, CLIST, ECLIST, LCLIST,
 	IF, THEN, ELSE, CASE,
 	FOR, IN, DO,
 	TRUE, FALSE, RT, RO, UNKNOWN, GENERIC,
-	FROM, GW, NET, MASK, PROTO, SOURCE, SCOPE, DEST, IFNAME, IFINDEX, WEIGHT, GW_MPLS, ONLINK,
+	FROM, GW, NET, PROTO, SOURCE, SCOPE, DEST, IFNAME, IFINDEX, WEIGHT, GW_MPLS, ONLINK,
 	PREFERENCE,
-	ROA_CHECK, ASN, SRC, DST,
-	IS_V4, IS_V6,
-	LEN, MAXLEN,
-	DATA, DATA1, DATA2,
+	ROA_CHECK,
 	DEFINED,
 	ADD, DELETE, RESET,
-	PREPEND, FIRST, LAST, LAST_NONAGGREGATED,
-	MIN, MAX,
+	PREPEND,
 	EMPTY,
 	FILTER, WHERE, EVAL, ATTRIBUTE,
 	BT_ASSERT, BT_TEST_SUITE, BT_CHECK_ASSIGN, BT_TEST_SAME, FORMAT)
 
+CF_METHODS(IS_V4, TYPE, IP, RD, LEN, MAXLEN, ASN, SRC, DST, MASK,
+	FIRST, LAST, LAST_NONAGGREGATED, DATA, DATA1, DATA2, MIN, MAX,
+	EMPTY, PREPEND, ADD, DELETE, FILTER)
+
 %nonassoc THEN
 %nonassoc ELSE