diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index afbfe21..8281f27 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -1,7 +1,12 @@
 ROOT ::= ATOM*
+EXPR ::=
+| ATOM 
+| CALL
+CALL ::= opar EXPR EXPR* cpar
 ATOM ::= 
 | int 
 | float 
 | bool
 | string
 | symbol
+| ident
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index df906d0..128d7d1 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -16,6 +16,8 @@ add_library(moka-core
     value.c
     exec.c
     moka.c
+    symtable.c
+    native.c
 )
 
 target_compile_options(moka-core
diff --git a/lib/commons.h b/lib/commons.h
index 4250fbc..09e6e4d 100644
--- a/lib/commons.h
+++ b/lib/commons.h
@@ -9,6 +9,8 @@
 #include <stdbool.h>
 #include <ctype.h>
 
+typedef size_t MOKA;
+
 #define MK_STRLEN 4096
 #define MK_ENUM_ENUM(X) X
 #define MK_ENUM_STRING(X) #X
diff --git a/lib/compiler.c b/lib/compiler.c
index 342eda6..9c10f2a 100644
--- a/lib/compiler.c
+++ b/lib/compiler.c
@@ -1,6 +1,6 @@
 #include "compiler.h"
 
-void compiler_init(struct compiler* self, 
+void compiler_init(struct compiler* self,
                    struct status* status)
 {
     assert(self);
@@ -12,22 +12,43 @@ void compiler_free(struct compiler* self)
     assert(self);
 }
 
-void compiler_compile(struct compiler* self, 
+void compiler_compile(struct compiler* self,
                       struct node* node,
-                      struct prog* prog)
+                      struct prog* prog,
+                      struct symtable* symtable)
 {
     assert(self); assert(node); assert(prog);
-    
+
     switch (node->kind)
     {
         case NODE_ROOT: {
             for (size_t i=0; i<node->children.size; i++)
             {
                 struct node* child = node->children.data[i];
-                compiler_compile(self, child, prog);
+                compiler_compile(self, child, prog, symtable);
             }
         } break;
 
+        case NODE_CALL: {
+            for (size_t i=0; i<node->children.size - 1; i++)
+            {
+                // size_t k = node->children.size - 1 - i;
+                // struct node* child = node->children.data[k];
+                // compiler_compile(self, child, prog, symtable);
+                size_t k = node->children.size - 1 - i;
+                struct node* child = node->children.data[k];
+                struct value* val = malloc(sizeof(struct value));
+                value_init_lazy(val, child, child->line);
+                size_t addr = prog_add_new_value(prog, val);
+                prog_add_instruction(prog, OP_PUSH, addr);
+            }
+
+            struct node* child = node->children.data[0];
+            compiler_compile(self, child, prog, symtable);
+
+            prog_add_instruction(prog, OP_CALL, node->children.size - 1);
+        } break;
+
         case NODE_INT: {
             struct value* value = malloc(sizeof(struct value));
             int val = atoi(node->token->value);
@@ -65,6 +86,27 @@ void compiler_compile(struct compiler* self,
             ssize_t addr = prog_add_new_value(prog, value);
             prog_add_instruction(prog, OP_PUSH, addr);
         } break;
+
+        case NODE_IDENT: {
+            struct entry const* entry = symtable_try_get(symtable,
+                                                   node->token->value);
+            if (!entry)
+            {
+                status_push(self->status, STATUS_ERROR, node->line,
+                            "undefined <%s>", node->token->value);
+                return;
+            }
+
+            if (entry->is_local)
+            {
+                prog_add_instruction(prog, OP_LOCAL_LOAD, entry->addr);
+            }
+            else
+            {
+                prog_add_instruction(prog, OP_GLOBAL_LOAD, entry->addr);
+            }
+        } break;
+
         default: {
             fprintf(stderr, "cannot compile node %s\n",
                     NodeKindStr[node->kind]);
diff --git a/lib/compiler.h b/lib/compiler.h
index f2bf6f4..c2b255f 100644
--- a/lib/compiler.h
+++ b/lib/compiler.h
@@ -5,6 +5,7 @@
 #include "status.h"
 #include "prog.h"
 #include "node.h"
+#include "symtable.h"
 
 struct compiler
 {
@@ -17,5 +18,6 @@ void compiler_free(struct compiler* self);
 
 void compiler_compile(struct compiler* self, 
                       struct node* node,
-                      struct prog* prog);
+                      struct prog* prog,
+                      struct symtable* symtable);
 #endif
diff --git a/lib/exec.c b/lib/exec.c
index c3bb43f..b2a5f56 100644
--- a/lib/exec.c
+++ b/lib/exec.c
@@ -37,6 +37,34 @@ void exec_instr(struct exec* self,
 
     switch (instr->opcode)
     {
+        case OP_CALL: {
+            MOKA fun = moka_pop(moka);
+            struct vec args;
+            vec_init(&args);
+
+            for (ssize_t i=0; i<param; i++)
+            {
+                MOKA arg = moka_pop(moka);
+                vec_push(&args, (void*) arg);
+            }
+
+            struct value* val = moka->global_values.data[
+                moka_get_ref(moka, fun)
+            ];
+
+            assert(val->type == TY_NATIVE);
+            struct native* native = val->data.native;
+            (native->fun)(moka, &args);
+
+            vec_free(&args);
+            self->pc++;
+        } break;
+
+        case OP_GLOBAL_LOAD: {
+            moka_push_ref(moka, param, 0);
+            self->pc++;
+        } break;
+
         case OP_PUSH: {
             struct value* value = prog->values.data[param];
             switch (value->type)
@@ -61,6 +89,9 @@ void exec_instr(struct exec* self,
                     moka_push_symbol(moka, value->data.sym, value->line);
                 } break;
 
+                case TY_LAZY: {
+                    moka_push_lazy(moka, value->data.lazy, value->line);
+                } break;
                 default: {
                     fprintf(stderr,
                         "cannot push value of type <%s>\n",
diff --git a/lib/lexer.c b/lib/lexer.c
index 4ba70f7..24db680 100644
--- a/lib/lexer.c
+++ b/lib/lexer.c
@@ -16,12 +16,16 @@ void lexer_init(struct lexer* self,
     }
     self->context.line = 1;
     self->context.cursor = 0;
+    str_init(&self->separators);
+    str_push(&self->separators, '(');
+    str_push(&self->separators, ')');
 }
 
 void lexer_free(struct lexer* self)
 {
     assert(self);
     free(self->source);
+    str_free(&self->separators);
 }
 
 struct token* lexer_try_new_next(struct lexer* self)
@@ -31,6 +35,16 @@ struct token* lexer_try_new_next(struct lexer* self)
 
     lexer_skip_spaces(self);
 
+    if ( (tok=lexer_try_new_text(self, TOKEN_OPAR, "(")) )
+    {
+        return tok;
+    }
+
+    if ( (tok=lexer_try_new_text(self, TOKEN_CPAR, ")")) )
+    {
+        return tok;
+    }
+
     if ( (tok=lexer_try_new_float(self)) )
     {
         return tok;
@@ -61,6 +75,11 @@ struct token* lexer_try_new_next(struct lexer* self)
         return tok;
     }
 
+    if ( (tok=lexer_try_new_ident(self)) )
+    {
+        return tok;
+    }
+
     if (self->context.cursor < self->len)
     {
         struct str str;
@@ -88,6 +107,25 @@ struct token* lexer_try_new_next(struct lexer* self)
     return tok;
 }
 
+void lexer_skip(struct lexer* self, TokenKind kind)
+{
+    assert(self);
+    struct token* tok = lexer_try_new_next(self);
+    assert(tok);
+
+    if (tok->kind != kind)
+    {
+        status_push(self->status, STATUS_ERROR, tok->line,
+                    "expected token <%s>, got <%s>",
+                    TokenKindStr[kind] + strlen("TOKEN_"),
+                    TokenKindStr[tok->kind] + strlen("TOKEN_")
+                    );
+    }
+
+    token_free(tok);
+    free(tok);
+}
+
 void lexer_skip_spaces(struct lexer* self)
 {
     assert(self);
@@ -288,6 +326,36 @@ struct token* lexer_try_new_symbol(struct lexer* self)
     return tok;
 }
 
+struct token* lexer_try_new_ident(struct lexer* self)
+{
+    assert(self);
+    size_t cursor = self->context.cursor;
+
+    if (cursor >= self->len
+    || isdigit(self->source[cursor]))
+    {
+        return NULL;
+    }
+
+    struct str value;
+    str_init(&value);
+
+    while (cursor < self->len
+        && lexer_is_ident(self, cursor))
+    {
+        char c = self->source[cursor];
+        str_push(&value, c);
+        cursor++;
+    }
+
+    struct token* tok = malloc(sizeof(struct token));
+    token_init(tok, TOKEN_IDENT, value.value);
+    str_free(&value);
+
+    self->context.cursor = cursor;
+    return tok;
+}
+
 bool lexer_is_sep(struct lexer* self, size_t index)
 {
     assert(self);
@@ -298,9 +366,34 @@ bool lexer_is_sep(struct lexer* self, size_t index)
     }
 
     char c = self->source[index];
+
+    for (size_t i=0; i<self->separators.size; i++)
+    {
+        if (c == self->separators.value[i])
+        {
+            return true;
+        }
+    }
+
     return isspace(c);
 }
 
+bool lexer_is_ident(struct lexer* self, size_t index)
+{
+    assert(self);
+    if (index >= self->len)
+    {
+        return false;
+    }
+    char c = self->source[index];
+
+    return isalnum(c)
+    || c == '_'
+    || c == '!'
+    || c == '?'
+    || c == '-';
+}
+
 struct token* lexer_try_new_text(struct lexer* self,
                                  TokenKind kind,
                                  char const* text)
diff --git a/lib/lexer.h b/lib/lexer.h
index f891efd..bb8a901 100644
--- a/lib/lexer.h
+++ b/lib/lexer.h
@@ -28,14 +28,18 @@ void lexer_init(struct lexer* self,
 void lexer_free(struct lexer* self);
 
 struct token* lexer_try_new_next(struct lexer* self);
+void lexer_skip(struct lexer* self, TokenKind kind);
 void lexer_skip_spaces(struct lexer* self);
 
 struct token* lexer_try_new_int(struct lexer* self);
 struct token* lexer_try_new_float(struct lexer* self);
 struct token* lexer_try_new_string(struct lexer* self);
 struct token* lexer_try_new_symbol(struct lexer* self);
+struct token* lexer_try_new_ident(struct lexer* self);
 
 bool lexer_is_sep(struct lexer* self, size_t index);
+bool lexer_is_ident(struct lexer* self, size_t index);
+
 struct token* lexer_try_new_text(struct lexer* self,
                                  TokenKind kind,
                                  char const* text);
diff --git a/lib/moka.c b/lib/moka.c
index 4912bcd..764831e 100644
--- a/lib/moka.c
+++ b/lib/moka.c
@@ -1,8 +1,14 @@
 #include "moka.h"
+#include "node.h"
+#include "compiler.h"
+#include "prog.h"
+#include "exec.h"
 
-void moka_init(struct moka* self)
+void moka_init(struct moka* self, struct status* status)
 {
     assert(self);
+    self->status = status;
+    symtable_init(&self->symtable);
     vec_init(&self->frame_stack);
     vec_init(&self->global_values);
 
@@ -28,11 +34,29 @@ void frame_free(struct frame* self)
 void moka_free(struct moka* self)
 {
     assert(self);
+    symtable_free(&self->symtable);
     vec_free_elements(&self->frame_stack, (void*) frame_free);
     vec_free(&self->frame_stack);
+    vec_free_elements(&self->global_values, (void*) value_free);
     vec_free(&self->global_values);
 }
 
+void moka_decl_native(struct moka* self,
+                      char* name,
+                      native_fun_t fun)
+{
+    struct native* native = malloc(sizeof(struct native));
+    native_init(native, fun);
+
+    struct value* value = malloc(sizeof(struct value));
+    value_init_native(value, native, 0);
+
+    vec_push(&self->global_values, value);
+    size_t addr = self->global_values.size - 1;
+
+    symtable_declare(&self->symtable, name, addr, false);
+}
+
 struct frame* moka_frame(struct moka* self)
 {
     assert(self);
@@ -58,6 +82,15 @@ MOKA moka_top(struct moka* self)
     return val;
 }
 
+MOKA moka_pop(struct moka* self)
+{
+    assert(self);
+    struct frame* frame = moka_frame(self);
+    assert(frame->stack.size > 0);
+    MOKA val = (MOKA) frame->stack.data[frame->stack.size - 1];
+    vec_pop(&frame->stack);
+    return val;
+}
 bool moka_is(struct moka* self, MOKA value, TypeKind type)
 {
     return moka_type_of(self, value) == type;
@@ -73,6 +106,12 @@ TypeKind moka_type_of(struct moka* self, MOKA value)
 
 void moka_dump(struct moka* self, MOKA value)
 {
+    if (moka_is(self, value, TY_REF))
+    {
+        printf("&%zu", moka_get_ref(self, value));
+        return;
+    }
+
     if (moka_is(self, value, TY_INT))
     {
         printf("%d", moka_get_int(self, value));
@@ -214,3 +253,112 @@ char* moka_get_symbol(struct moka* self, MOKA value)
     assert(val->type == TY_SYMBOL);
     return val->data.sym;
 }
+
+MOKA moka_push_ref(struct moka* self, size_t value, int line)
+{
+    assert(self);
+    struct frame* frame = moka_frame(self);
+    struct value* val = malloc(sizeof(struct value));
+    value_init_ref(val, value, line);
+    vec_push(&frame->local_values, val);
+    size_t addr = frame->local_values.size - 1;
+    vec_push(&frame->stack, (void*) addr);
+    return addr;
+}
+
+size_t moka_get_ref(struct moka* self, MOKA value)
+{
+    assert(self);
+    struct frame* frame = moka_frame(self);
+    struct value* val = frame->local_values.data[value];
+    assert(val->type == TY_REF);
+    return val->data.ref;
+}
+
+MOKA moka_push_native(struct moka* self, native_fun_t value, int line)
+{
+    assert(self);
+    assert(value);
+
+    struct native* native = malloc(sizeof(struct native));
+    native_init(native, value);
+
+    struct value* val = malloc(sizeof(struct value));
+    value_init_native(val, native, line);
+
+    vec_push(&self->global_values, val);
+    size_t addr = self->global_values.size - 1;
+
+    return moka_push_ref(self, addr, line);
+}
+
+native_fun_t moka_get_native(struct moka* self, MOKA value)
+{
+    assert(self);
+
+    size_t addr = moka_get_ref(self, value);
+    struct value const* val = self->global_values.data[addr];
+    struct native const* native = val->data.native;
+    return native->fun;
+}
+
+MOKA moka_eval_lazy(struct moka* self, MOKA lazy_value)
+{
+    assert(self);
+    struct node* node = moka_get_lazy(self, lazy_value);
+
+    struct compiler compiler;
+    compiler_init(&compiler, self->status);
+
+    struct prog prog;
+    prog_init(&prog);
+
+    compiler_compile(
+        &compiler,
+        node,
+        &prog,
+        &self->symtable);
+
+    if (!status_is_ok(self->status))
+    {
+        status_dump(self->status);
+        moka_push_int(self, 0, 0);
+        goto free_prog;
+    }
+
+    struct exec exec;
+    exec_init(&exec);
+
+    exec_prog(&exec, self, &prog);
+
+    exec_free(&exec);
+free_prog:
+    prog_free(&prog);
+    compiler_free(&compiler);
+
+    return moka_pop(self);
+}
+
+MOKA moka_push_lazy(struct moka* self, struct node* value, int line)
+{
+    assert(self);
+    assert(value);
+
+    struct value* val = malloc(sizeof(struct value));
+    value_init_lazy(val, value, line);
+
+    struct frame* frame = moka_frame(self);
+    vec_push(&frame->local_values, val);
+    size_t addr = frame->local_values.size - 1;
+    vec_push(&frame->stack, (void*) addr);
+    return addr;
+}
+
+struct node* moka_get_lazy(struct moka* self, MOKA value)
+{
+    assert(self);
+    struct frame* frame = moka_frame(self);
+    struct value* val = frame->local_values.data[value];
+    assert(val->type == TY_LAZY);
+    return val->data.lazy;
+}
diff --git a/lib/moka.h b/lib/moka.h
index fd80f77..2b6baf6 100644
--- a/lib/moka.h
+++ b/lib/moka.h
@@ -4,8 +4,7 @@
 #include "commons.h"
 #include "vec.h"
 #include "value.h"
-
-typedef size_t MOKA;
+#include "symtable.h"
 
 struct frame
 {
@@ -15,18 +14,25 @@ struct frame
 
 struct moka
 {
+    struct status* status;
+    struct symtable symtable;
     struct vec frame_stack;
     struct vec global_values;
 };
 
-void moka_init(struct moka* self);
+void moka_init(struct moka* self, struct status* status);
 void frame_init(struct frame* self);
 void frame_free(struct frame* self);
 void moka_free(struct moka* self);
 
+void moka_decl_native(struct moka* self,
+                      char* name,
+                      native_fun_t fun);
+
 struct frame* moka_frame(struct moka* self);
 bool moka_has_top(struct moka* self);
 MOKA moka_top(struct moka* self);
+MOKA moka_pop(struct moka* self);
 
 bool moka_is(struct moka* self, MOKA value, TypeKind type);
 TypeKind moka_type_of(struct moka* self, MOKA value);
@@ -48,4 +54,13 @@ char* moka_get_string(struct moka* self, MOKA value);
 MOKA moka_push_symbol(struct moka* self, char const* value, int line);
 char* moka_get_symbol(struct moka* self, MOKA value);
 
+MOKA moka_push_ref(struct moka* self, size_t value, int line);
+size_t moka_get_ref(struct moka* self, MOKA value);
+
+MOKA moka_push_native(struct moka* self, native_fun_t value, int line);
+native_fun_t moka_get_native(struct moka* self, MOKA value);
+
+MOKA moka_eval_lazy(struct moka* self, MOKA lazy_value);
+MOKA moka_push_lazy(struct moka* self, struct node* value, int line);
+struct node* moka_get_lazy(struct moka* self, MOKA value);
 #endif
diff --git a/lib/native.c b/lib/native.c
new file mode 100644
index 0000000..882ce07
--- /dev/null
+++ b/lib/native.c
@@ -0,0 +1,12 @@
+#include "native.h"
+
+void native_init(struct native* self, native_fun_t fun)
+{
+    assert(self);
+    self->fun = fun;
+}
+
+void native_free(struct native* self)
+{
+    assert(self);
+}
diff --git a/lib/native.h b/lib/native.h
new file mode 100644
index 0000000..7f17ad4
--- /dev/null
+++ b/lib/native.h
@@ -0,0 +1,20 @@
+#ifndef MK_NATIVE_H
+#define MK_NATIVE_H
+
+#include "commons.h"
+#include "vec.h"
+
+struct moka;
+
+typedef MOKA (*native_fun_t)(struct moka*, struct vec* args);
+
+
+struct native 
+{
+    native_fun_t fun;
+};
+
+void native_init(struct native* self, native_fun_t fun);
+void native_free(struct native* self);
+
+#endif
diff --git a/lib/node.c b/lib/node.c
index 2bc67d2..c53d2b9 100644
--- a/lib/node.c
+++ b/lib/node.c
@@ -16,6 +16,8 @@ void node_init(struct node* self,
 
 void node_free(struct node* self)
 {
+    assert(self);
+
     if (self->token)
     {
         token_free(self->token);
diff --git a/lib/node.h b/lib/node.h
index 2f7137c..84cc8c3 100644
--- a/lib/node.h
+++ b/lib/node.h
@@ -9,7 +9,8 @@
 #define NODE_KIND(G) \
 G(NODE_ROOT), \
 G(NODE_INT), G(NODE_FLOAT), G(NODE_BOOL), \
-G(NODE_STRING), G(NODE_SYMBOL)
+G(NODE_STRING), G(NODE_SYMBOL), G(NODE_CALL),\
+G(NODE_IDENT)
 
 MK_ENUM_H(NodeKind, NODE_KIND);
 
diff --git a/lib/parser.c b/lib/parser.c
index 32645b9..b01027f 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -46,20 +46,81 @@ struct node* parser_try_new_root(struct parser* self)
 
     while (!lexer_end(self->lexer))
     {
-        struct node* atom = MK_TRY(parser_try_new_atom);
-        if (!atom && !lexer_end(self->lexer))
+        struct node* expr = MK_TRY(parser_try_new_expr);
+        if (!expr && !lexer_end(self->lexer))
         {
             node_free(root);
             free(root);
             return NULL;
         }
 
-        node_add_new_child(root, atom);
+        node_add_new_child(root, expr);
     }
 
     return root;
 }
 
+struct node* parser_try_new_expr(struct parser* self)
+{
+    assert(self);
+
+    if (lexer_next_is(self->lexer, TOKEN_OPAR, 0))
+    {
+        return MK_TRY(parser_try_new_call);
+    }
+
+    return MK_TRY(parser_try_new_atom);
+}
+
+struct node* parser_try_new_call(struct parser* self)
+{
+    assert(self);
+
+    if (!lexer_next_is(self->lexer, TOKEN_OPAR, 0))
+    {
+        return NULL;
+    }
+
+    lexer_skip(self->lexer, TOKEN_OPAR);
+
+    struct node* target = MK_TRY(parser_try_new_expr);
+    
+    if (!target)
+    {
+        return NULL;
+    }
+
+    struct node* call = malloc(sizeof(struct node));
+    node_init(call, NODE_CALL, NULL, target->line);
+    node_add_new_child(call, target);
+
+    while (!lexer_next_is(self->lexer, TOKEN_CPAR, 0))
+    {
+        struct node* arg = MK_TRY(parser_try_new_expr);
+
+        if (!arg)
+        {
+            node_free(target); free(target);
+            node_free(call); free(call);
+            node_free(arg); free(arg);
+            return NULL;
+        }
+
+        node_add_new_child(call, arg);
+    }
+
+    if (!lexer_next_is(self->lexer, TOKEN_CPAR, 0))
+    {
+        node_free(target); free(target);
+        node_free(call); free(call);
+        return NULL;
+    }
+
+    lexer_skip(self->lexer, TOKEN_CPAR);
+
+    return call;
+}
+
 struct node* parser_try_new_atom(struct parser* self)
 {
     assert(self);
@@ -113,6 +174,16 @@ struct node* parser_try_new_atom(struct parser* self)
                   self->lexer->context.line);
         return node;
     }
+
+    if (lexer_next_is(self->lexer, TOKEN_IDENT, 0))
+    {
+        struct node* node = malloc(sizeof(struct node));
+        struct token* tok = lexer_try_new_next(self->lexer);
+        assert(tok);
+        node_init(node, NODE_IDENT, tok,
+                  self->lexer->context.line);
+        return node;
+    }
     return NULL;
 }
 
diff --git a/lib/parser.h b/lib/parser.h
index 1754a19..1246c6f 100644
--- a/lib/parser.h
+++ b/lib/parser.h
@@ -19,6 +19,8 @@ struct node* parser_try(struct parser* self,
                         struct node* (*rule)(struct parser*));
 
 struct node* parser_try_new_root(struct parser* self);
+struct node* parser_try_new_expr(struct parser* self);
+struct node* parser_try_new_call(struct parser* self);
 struct node* parser_try_new_atom(struct parser* self);
 
 #endif
diff --git a/lib/prog.c b/lib/prog.c
index aeab237..ddddfc1 100644
--- a/lib/prog.c
+++ b/lib/prog.c
@@ -7,6 +7,7 @@ void prog_init(struct prog* self)
     assert(self);
     vec_init(&self->instructions);
     vec_init(&self->values);
+    self->stack_addr = 0;
 }
 
 void prog_free(struct prog* self)
@@ -30,6 +31,21 @@ size_t prog_add_instruction(struct prog* self,
 
     vec_push(&self->instructions, instr);
 
+    switch (opcode)
+    {
+        case OP_CALL:
+        case OP_GLOBAL_LOAD:
+        case OP_PUSH: {
+            self->stack_addr++;
+        } break;
+
+        default: {
+            fprintf(stderr, "cannot find stack address of <%s>\n",
+                    OpcodeKindStr[opcode]);
+            abort();
+        } break;
+    }
+
     return self->instructions.size - 1;
 }
 
diff --git a/lib/prog.h b/lib/prog.h
index 7ff0dfe..d5f1a5e 100644
--- a/lib/prog.h
+++ b/lib/prog.h
@@ -6,7 +6,10 @@
 #include "value.h"
 
 #define OPCODE_KIND(G) \
-G(OP_PUSH)
+G(OP_PUSH), \
+G(OP_LOCAL_LOAD), \
+G(OP_GLOBAL_LOAD), \
+G(OP_CALL)
 
 MK_ENUM_H(OpcodeKind, OPCODE_KIND);
 
@@ -20,6 +23,7 @@ struct prog
 {
     struct vec instructions;
     struct vec values;
+    size_t stack_addr;
 };
 
 void prog_init(struct prog* self);
diff --git a/lib/symtable.c b/lib/symtable.c
new file mode 100644
index 0000000..c76af11
--- /dev/null
+++ b/lib/symtable.c
@@ -0,0 +1,101 @@
+#include "symtable.h"
+
+void entry_init(struct entry* self,
+                char const* name,
+                size_t addr,
+                bool is_local)
+{
+    assert(self);
+    self->name = strdup(name);
+    self->addr = addr;
+    self->is_local = is_local;
+}
+
+void entry_free(struct entry* self)
+{
+    assert(self);
+    free(self->name);
+}
+
+void env_init(struct env* self, struct env* parent)
+{
+    assert(self);
+    vec_init(&self->entries);
+    self->parent = parent;
+}
+
+void env_free(struct env* self)
+{
+    assert(self);
+
+    if (self->parent)
+    {
+        env_free(self->parent);
+        free(self->parent);
+        self->parent = NULL;
+    }
+
+    vec_free_elements(&self->entries, (void*) entry_free);
+    vec_free(&self->entries);
+}
+
+struct entry* env_try_get(struct env* self, char* name)
+{
+    assert(self);
+    assert(name);
+
+    for (size_t i=0; i<self->entries.size; i++)
+    {
+        struct entry* entry = self->entries.data[i];
+
+        if (strcmp(entry->name, name) == 0)
+        {
+            return entry;
+        }
+    }
+
+    if (self->parent)
+    {
+        return env_try_get(self->parent, name);
+    }
+
+    return NULL;
+}
+
+void symtable_init(struct symtable* self)
+{
+    assert(self);
+    self->root = malloc(sizeof(struct env));
+    env_init(self->root, NULL);
+}
+
+void symtable_free(struct symtable* self)
+{
+    assert(self);
+    env_free(self->root);
+    free(self->root);
+}
+
+void symtable_declare(struct symtable* self,
+                      char* name,
+                      size_t addr,
+                      bool is_local)
+{
+    assert(self);
+    assert(name);
+    assert(self->root);
+
+    struct entry* entry = malloc(sizeof(struct entry));
+    entry_init(entry, name, addr, is_local);
+
+    vec_push(&self->root->entries, entry);
+}
+
+struct entry* symtable_try_get(struct symtable* self, char* name)
+{
+    assert(self);
+    assert(name);
+
+    return env_try_get(self->root, name);
+
+}
diff --git a/lib/symtable.h b/lib/symtable.h
new file mode 100644
index 0000000..d3c162e
--- /dev/null
+++ b/lib/symtable.h
@@ -0,0 +1,45 @@
+#ifndef MK_SYMTABLE_H
+#define MK_SYMTABLE_H
+
+#include "commons.h"
+#include "vec.h"
+
+struct entry
+{
+    char* name;
+    size_t addr;
+    bool is_local;
+};
+
+struct env
+{
+    struct vec entries;
+    struct env* parent;
+};
+
+struct symtable
+{
+    struct env* root;
+};
+
+void entry_init(struct entry* self,
+                char const* name,
+                size_t addr,
+                bool is_local);
+void entry_free(struct entry* self);
+
+void env_init(struct env* self, struct env* parent);
+void env_free(struct env* self);
+struct entry* env_try_get(struct env* self, char* name);
+
+void symtable_init(struct symtable* self);
+void symtable_free(struct symtable* self);
+
+void symtable_declare(struct symtable* self,
+                      char* name,
+                      size_t addr,
+                      bool is_local);
+
+struct entry* symtable_try_get(struct symtable* self, char* name);
+
+#endif
diff --git a/lib/token.h b/lib/token.h
index 2135ba4..62aa117 100644
--- a/lib/token.h
+++ b/lib/token.h
@@ -6,7 +6,8 @@
 #define TOKEN_KIND(G) \
 G(TOKEN_INT), G(TOKEN_FLOAT), \
 G(TOKEN_BOOL), G(TOKEN_STRING), \
-G(TOKEN_SYMBOL)
+G(TOKEN_SYMBOL), G(TOKEN_IDENT), \
+G(TOKEN_OPAR), G(TOKEN_CPAR)
 
 MK_ENUM_H(TokenKind, TOKEN_KIND);
 
diff --git a/lib/value.c b/lib/value.c
index 25b0675..77394e9 100644
--- a/lib/value.c
+++ b/lib/value.c
@@ -1,4 +1,5 @@
 #include "value.h"
+#include "node.h"
 
 MK_ENUM_C(TypeKind, TYPE_KIND);
 
@@ -44,6 +45,32 @@ void value_init_symbol(struct value* self, char const* value, int line)
     self->line = line;
 }
 
+void value_init_ref(struct value* self, size_t value, int line)
+{
+    assert(self);
+    self->data.ref = value;
+    self->type = TY_REF;
+    self->line = line;
+}
+
+void value_init_native(struct value* self, struct native* value, int line)
+{
+    assert(self);
+    assert(value);
+    self->data.native = value;
+    self->type = TY_NATIVE;
+    self->line = line;
+}
+
+void value_init_lazy(struct value* self, struct node* value, int line)
+{
+    assert(self);
+    assert(value);
+    self->data.lazy = value;
+    self->type = TY_LAZY;
+    self->line = line;
+}
+
 void value_free(struct value* self)
 {
     assert(self);
@@ -58,4 +85,9 @@ void value_free(struct value* self)
         free(self->data.sym);
     }
 
+    if (self->type == TY_NATIVE)
+    {
+        native_free(self->data.native);
+        free(self->data.native);
+    }
 }
diff --git a/lib/value.h b/lib/value.h
index 78bd79a..00f89d5 100644
--- a/lib/value.h
+++ b/lib/value.h
@@ -2,10 +2,12 @@
 #define MK_VALUE_H
 
 #include "commons.h"
+#include "native.h"
 
 #define TYPE_KIND(G) \
 G(TY_INT), G(TY_FLOAT), G(TY_BOOL), \
-G(TY_STRING), G(TY_SYMBOL)
+G(TY_STRING), G(TY_SYMBOL), G(TY_REF), \
+G(TY_NATIVE), G(TY_LAZY)
 
 MK_ENUM_H(TypeKind, TYPE_KIND);
 
@@ -16,6 +18,9 @@ union value_data
     bool boolean;
     char* str;
     char* sym;
+    size_t ref;
+    struct native* native;
+    struct node* lazy;
 };
 
 struct value
@@ -30,6 +35,9 @@ void value_init_float(struct value* self, float value, int line);
 void value_init_bool(struct value* self, bool value, int line);
 void value_init_string(struct value* self, char const* value, int line);
 void value_init_symbol(struct value* self, char const* value, int line);
+void value_init_ref(struct value* self, size_t value, int line);
+void value_init_native(struct value* self, struct native* value, int line);
+void value_init_lazy(struct value* self, struct node* value, int line);
 void value_free(struct value* self);
 
 #endif
diff --git a/src/main.c b/src/main.c
index b86237f..ad87625 100644
--- a/src/main.c
+++ b/src/main.c
@@ -46,16 +46,17 @@ int main(int argc, char** argv)
     struct prog prog;
     prog_init(&prog);
 
-    compiler_compile(&compiler, root, &prog);
+
+    struct moka moka;
+    moka_init(&moka, &status);
+    compiler_compile(&compiler, root, &prog, &moka.symtable);
 
     if (!status_is_ok(&status))
     {
         status_dump(&status);
-        goto free_compiler;
+        goto free_moka;
     }
 
-    struct moka moka;
-    moka_init(&moka);
 
     struct exec exec;
     exec_init(&exec);
@@ -70,9 +71,9 @@ int main(int argc, char** argv)
     }
 
     exec_free(&exec);
+free_moka:
     moka_free(&moka);
     prog_free(&prog);
-free_compiler:
     compiler_free(&compiler);
     node_free(root);
     free(root);
diff --git a/tests/lexer.h b/tests/lexer.h
index 32fa986..bca2b59 100644
--- a/tests/lexer.h
+++ b/tests/lexer.h
@@ -75,10 +75,20 @@ START_TEST(lexer_atom)
 }
 END_TEST
 
+START_TEST(lexer_funcall)
+{
+    test_lexer(" (_0pizza?!) ", 3,
+               TOKEN_OPAR, "(",
+               TOKEN_IDENT, "_0pizza?!",
+               TOKEN_CPAR, ")"
+    );
+}
+END_TEST
 void register_lexer(Suite* suite)
 {
     TCase* tcase = tcase_create("Lexer");
     tcase_add_test(tcase, lexer_atom);
+    tcase_add_test(tcase, lexer_funcall);
     suite_add_tcase(suite, tcase);
 }
 
diff --git a/tests/parser.h b/tests/parser.h
index 94eff23..90ad0bc 100644
--- a/tests/parser.h
+++ b/tests/parser.h
@@ -59,10 +59,24 @@ START_TEST(parser_atom)
 }
 END_TEST
 
+START_TEST(parser_call)
+{
+    test_parser("ROOT(CALL(IDENT[hello-noparam]))", 
+                " (hello-noparam) ");
+
+    test_parser("ROOT(CALL(IDENT[hello],SYMBOL[world]))", 
+                " (hello 'world) ");
+
+    test_parser("ROOT(CALL(IDENT[is-ok?],BOOL[true],INT[4]))", 
+                " (is-ok? true 4) ");
+}
+END_TEST
+
 void register_parser(Suite* suite)
 {
     TCase* tcase = tcase_create("Parser");
     tcase_add_test(tcase, parser_atom);
+    tcase_add_test(tcase, parser_call);
 
     suite_add_tcase(suite, tcase);
 }