diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index 448143e..766e2ee 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -1,3 +1,7 @@
 MODULE ::= EXPR*
 EXPR ::=
-int
+| int
+| ident
+| CALL
+
+CALL ::= opar ident EXPR* cpar
diff --git a/libstd/common.hpp b/libstd/common.hpp
new file mode 100644
index 0000000..396b0a9
--- /dev/null
+++ b/libstd/common.hpp
@@ -0,0 +1,9 @@
+#ifndef COMMON_HPP
+#define COMMON_HPP
+
+#include "../src/Zarn.hpp"
+using namespace zn;
+
+#define STDARGS std::vector<std::shared_ptr<Constant>>
+
+#endif
diff --git a/libstd/fun.cpp b/libstd/fun.cpp
new file mode 100644
index 0000000..81c31ed
--- /dev/null
+++ b/libstd/fun.cpp
@@ -0,0 +1,36 @@
+#include "fun.hpp"
+
+std::shared_ptr<Constant> println(STDARGS args)
+{
+  std::string sep;
+
+  for (auto const& arg: args)
+    {
+      std::cout << sep << arg->string();
+      sep = " ";
+    }
+
+  std::cout << std::endl;
+
+  return std::make_shared<Constant>(TYPE_NIL, args[0]->loc());
+}
+
+std::shared_ptr<Constant> assert_eq(STDARGS args)
+{
+  bool equals = args[0]->equals(*args[1]);
+  auto loc = args[0]->loc();
+
+  if (!equals)
+    {
+      std::cerr << loc.file_path().string() << ":" << loc.line();
+      std::cerr << " ASSERTION FAILED: ";
+
+      std::cerr << "expected '" << args[0]->string() << "', "
+                << "got '" << args[1]->string() << "'."
+                << std::endl;
+
+      exit(-1);
+    }
+
+  return std::make_shared<Constant>(TYPE_NIL, loc, 0);
+}
diff --git a/libstd/fun.hpp b/libstd/fun.hpp
new file mode 100644
index 0000000..dc82c87
--- /dev/null
+++ b/libstd/fun.hpp
@@ -0,0 +1,9 @@
+#ifndef FUN_HPP
+#define FUN_HPP
+
+#include "common.hpp"
+
+std::shared_ptr<Constant> println(STDARGS args);
+std::shared_ptr<Constant> assert_eq(STDARGS args);
+
+#endif
diff --git a/libstd/std.cpp b/libstd/std.cpp
new file mode 100644
index 0000000..b6297ba
--- /dev/null
+++ b/libstd/std.cpp
@@ -0,0 +1,19 @@
+#include "common.hpp"
+#include "fun.hpp"
+
+extern "C" void lib(Zarn& zarn)
+{
+  zarn.register_function("println",
+                         std::make_shared<Prototype>()
+                         ->param_any()
+                         ->param_variadic()
+                         ->ret(TYPE_NIL),
+                         println);
+
+  zarn.register_function("assert=",
+                         std::make_shared<Prototype>()
+                         ->param_any()
+                         ->param_any()
+                         ->ret(TYPE_NIL),
+                         assert_eq);
+}
diff --git a/meson.build b/meson.build
index 3124f82..cf9c799 100644
--- a/meson.build
+++ b/meson.build
@@ -7,8 +7,20 @@ project('zarn',
           'cpp_std=c++17'
         ])
 
+# CONFIGURATIONS
+# ==============
 extra_libdir = get_option('prefix') / get_option('libdir') / 'zarn'
 
+conf = configuration_data()
+conf.set('version', meson.project_version())
+conf.set('libdir', extra_libdir)
+
+configure_file(input: 'src/config.in.hpp',
+               output: 'config.hpp',
+               configuration: conf)
+
+# ZARN_LIB
+# ========
 zarn_lib = shared_library('zarn',
                           sources: [
                             'src/Module.cpp',
@@ -17,15 +29,35 @@ zarn_lib = shared_library('zarn',
                             'src/Logger.cpp',
                             'src/Lexer.cpp',
                             'src/Parser.cpp',
+                            'src/StaticPass.cpp',
                             'src/Compiler.cpp',
                             'src/Program.cpp',
                             'src/VM.cpp',
                             'src/Constant.cpp',
+                            'src/SymTable.cpp',
+                            'src/NativeFunction.cpp',
+                            'src/Prototype.cpp',
+                            'src/Zarn.cpp',
                           ],
                           install: true)
 
 zarn_dep = declare_dependency(link_with: zarn_lib)
 
+# STANDARD LIBRARY
+# ================
+shared_library('zarn-std',
+               sources: [
+                 'libstd/std.cpp',
+                 'libstd/fun.cpp',
+               ],
+               dependencies: [
+                 zarn_dep
+               ],
+               install_dir: extra_libdir,
+               install: true)
+
+# COMPILER
+# ========
 executable('zarn',
            sources: [
              'src/main.cpp'
@@ -35,6 +67,8 @@ executable('zarn',
            ],
            install: true)
 
+# TESTS
+# =====
 executable('zarn-tests',
            sources: [
              'tests/main.cpp',
diff --git a/src/Compiler.cpp b/src/Compiler.cpp
index 535fadc..0eca30f 100644
--- a/src/Compiler.cpp
+++ b/src/Compiler.cpp
@@ -4,8 +4,9 @@
 
 namespace zn
 {
-  /*explicit*/ Compiler::Compiler(Logger& logger)
+  /*explicit*/ Compiler::Compiler(Logger& logger, SymTable& sym)
     : m_logger { logger }
+    , m_sym { sym }
   {
   }
 
@@ -17,6 +18,8 @@ namespace zn
   {
     switch (node.type())
       {
+        // MODULES
+        // =======
       case NODE_MODULE: {
         for (size_t i=0; i<node.size(); i++)
           {
@@ -25,10 +28,44 @@ namespace zn
           }
       } break;
 
+        // FUNCTION STUFF
+        // ==============
+      case NODE_CALL: {
+        for (size_t i=0; i<node.size(); i++)
+          {
+            compile(*node.child_at(i), program);
+          }
+
+        program.append(OPCODE_CALL_NATIVE, node.size() - 1);
+      } break;
+
+        // VALUES
+        // ======
+      case NODE_IDENT: {
+        std::string ident = node.repr();
+        auto sym = m_sym.find(ident);
+        assert(sym);
+
+        if (sym->prototype)
+          {
+            auto ref = std::make_shared<Constant>(TYPE_REF,
+                                                  node.loc(),
+                                                  (int) sym->addr);
+            size_t val = program.add_constant(ref);
+            program.append(OPCODE_LOAD_CONST, val);
+          }
+        else
+          {
+            program.append(OPCODE_LOAD_LOCAL, sym->addr);
+          }
+
+      } break;
+
       case NODE_INT: {
         size_t addr = program
           .add_constant(std::make_shared<Constant>
-                        (TYPE_INT, std::stoi(node.repr())));
+                        (TYPE_INT, node.loc(),
+                         std::stoi(node.repr())));
         program.append(OPCODE_LOAD_CONST, addr);
       } break;
 
diff --git a/src/Compiler.hpp b/src/Compiler.hpp
index b6fe70b..c6a1d3a 100644
--- a/src/Compiler.hpp
+++ b/src/Compiler.hpp
@@ -5,6 +5,7 @@
 #include "Logger.hpp"
 #include "Node.hpp"
 #include "Program.hpp"
+#include "SymTable.hpp"
 
 namespace zn
 {
@@ -13,13 +14,14 @@ namespace zn
   class Compiler
   {
   public:
-    explicit Compiler(Logger& logger);
+    explicit Compiler(Logger& logger, SymTable& sym);
     virtual ~Compiler();
 
     void compile(Node const& node, Program& program);
 
   private:
     Logger& m_logger;
+    SymTable& m_sym;
   };
 }
 
diff --git a/src/Constant.cpp b/src/Constant.cpp
index 2d610ef..f91a516 100644
--- a/src/Constant.cpp
+++ b/src/Constant.cpp
@@ -2,8 +2,11 @@
 
 namespace zn
 {
-  /*explicit*/ Constant::Constant(Type type, value_t value)
+  /*explicit*/ Constant::Constant(Type type,
+                                  Loc const& loc,
+                                  constant_t value)
     : m_type { type }
+    , m_loc { loc }
     , m_value { value }
   {
   }
@@ -24,15 +27,16 @@ namespace zn
 
   std::string Constant::string() const
   {
-    if (auto val = std::get_if<int>(&(*m_value));
-        val)
+    switch (m_type)
       {
-        return std::to_string(*val);
+      case TYPE_NIL: return "<nil>";
+      case TYPE_INT: return std::to_string(std::get<int>(*m_value));
+      default: {
+        std::cerr << "cannot stringify "
+                  << (TypeStr[m_type] + strlen("TYPE_"))
+                  << std::endl;
+        abort();
+      } break;
       }
-
-    std::cerr << "cannot stringify "
-              << (TypeStr[m_type] + strlen("TYPE_"))
-              << std::endl;
-    abort();
   }
 }
diff --git a/src/Constant.hpp b/src/Constant.hpp
index 07e6037..45d7db2 100644
--- a/src/Constant.hpp
+++ b/src/Constant.hpp
@@ -2,24 +2,23 @@
 #define zn_CONSTANT_HPP
 
 #include "common.hpp"
-
-#define TYPES(G) \
-  G(TYPE_NIL),   \
-    G(TYPE_INT)
+#include "types.hpp"
+#include "Loc.hpp"
 
 namespace zn
 {
-  ZN_MK_ENUM(Type, TYPES);
-
-  using value_t = std::optional<std::variant<int>>;
+  using constant_t = std::optional<std::variant<int>>;
 
   class Constant
   {
   public:
-    explicit Constant(Type type, value_t value);
+    explicit Constant(Type type,
+                      Loc const& loc,
+                      constant_t value=std::nullopt);
     virtual ~Constant();
 
-    value_t value() const { return m_value; }
+    Loc loc() const { return m_loc; }
+    constant_t value() const { return m_value; }
     Type type() const { return m_type; }
 
     bool equals(Constant const& rhs) const;
@@ -27,7 +26,8 @@ namespace zn
 
   private:
     Type m_type;
-    value_t m_value;
+    Loc m_loc;
+    constant_t m_value;
   };
 }
 
diff --git a/src/Lexer.cpp b/src/Lexer.cpp
index 51557c1..e69a205 100644
--- a/src/Lexer.cpp
+++ b/src/Lexer.cpp
@@ -1,4 +1,6 @@
 #include "Lexer.hpp"
+#include "src/Node.hpp"
+#include <cctype>
 
 namespace zn
 {
@@ -6,7 +8,11 @@ namespace zn
     : m_logger { logger }
     , m_loc { loc }
   {
+    add_text("(", NODE_OPAR);
+    add_text(")", NODE_CPAR);
+
     m_scanners.push_back(std::bind(&Lexer::scan_int, this));
+    m_scanners.push_back(std::bind(&Lexer::scan_ident, this));
   }
 
   /*virtual*/ Lexer::~Lexer()
@@ -87,6 +93,32 @@ namespace zn
     return result;
   }
 
+  bool Lexer::is_sep(size_t index) const
+  {
+    if (index >= m_source.size()
+        || std::isspace(m_source[index]))
+      {
+        return true;
+      }
+
+    return m_separators.find(m_source[index]) != std::string::npos;
+  }
+
+  void Lexer::add_text(std::string const& text,
+                       NodeType type,
+                       bool has_value)
+  {
+    m_scanners.push_back(std::bind(&Lexer::scan_text,
+                                   this,
+                                   text,
+                                   type,
+                                   has_value));
+    if (text.size() == 1)
+      {
+        m_separators += text;
+      }
+  }
+
   void Lexer::skip_spaces()
   {
     while (m_cursor < m_source.size()
@@ -131,4 +163,52 @@ namespace zn
       repr
     };
   }
+
+  std::optional<ScanInfo> Lexer::scan_text(std::string const& text,
+                                           NodeType type,
+                                           bool has_value)
+  {
+    if (m_cursor + text.size() > m_source.size())
+      {
+        return std::nullopt;
+      }
+
+    for (size_t i=0; i<text.size(); i++)
+      {
+        if (text.at(i) != m_source.at(m_cursor + i))
+          {
+            return std::nullopt;
+          }
+      }
+
+    return ScanInfo {
+      m_cursor + text.size(),
+      type,
+      has_value ? text : ""
+    };
+  }
+
+  std::optional<ScanInfo> Lexer::scan_ident()
+  {
+    size_t cursor = m_cursor;
+    std::string repr;
+
+    while (cursor < m_source.size()
+           && !is_sep(cursor))
+      {
+        repr += m_source[cursor];
+        cursor++;
+      }
+
+    if (repr.empty())
+      {
+        return std::nullopt;
+      }
+
+    return ScanInfo {
+      cursor,
+      NODE_IDENT,
+      repr
+    };
+  }
 }
diff --git a/src/Lexer.hpp b/src/Lexer.hpp
index 5214c4b..48740c3 100644
--- a/src/Lexer.hpp
+++ b/src/Lexer.hpp
@@ -35,9 +35,20 @@ namespace zn
     size_t m_cursor;
     std::vector<scanner_t> m_scanners;
     Loc m_loc;
+    std::string m_separators;
+
+    bool is_sep(size_t index) const;
+
+    void add_text(std::string const& text,
+                  NodeType type,
+                  bool has_value=false);
 
     void skip_spaces();
     std::optional<ScanInfo> scan_int();
+    std::optional<ScanInfo> scan_text(std::string const& text,
+                                      NodeType type,
+                                      bool has_value);
+    std::optional<ScanInfo> scan_ident();
   };
 }
 
diff --git a/src/Module.cpp b/src/Module.cpp
index a949b05..1899164 100644
--- a/src/Module.cpp
+++ b/src/Module.cpp
@@ -3,7 +3,10 @@
 #include "Parser.hpp"
 #include "Program.hpp"
 #include "Compiler.hpp"
+#include "StaticPass.hpp"
 #include "VM.hpp"
+#include "NativeFunction.hpp"
+#include "config.hpp"
 
 namespace zn
 {
@@ -43,7 +46,12 @@ namespace zn
 
     auto ast = parser.parse(lexer.all());
 
-    Compiler compiler { m_logger };
+    m_zarn.load_std_library();
+
+    StaticPass static_pass { m_logger, m_sym };
+    static_pass.execute(*ast);
+
+    Compiler compiler { m_logger, m_sym };
     compiler.compile(*ast, m_program);
 
     m_vm.execute(m_program);
diff --git a/src/Module.hpp b/src/Module.hpp
index e2d19a0..33ab63a 100644
--- a/src/Module.hpp
+++ b/src/Module.hpp
@@ -5,6 +5,8 @@
 #include "Logger.hpp"
 #include "VM.hpp"
 #include "Program.hpp"
+#include "SymTable.hpp"
+#include "Zarn.hpp"
 
 namespace zn
 {
@@ -23,7 +25,9 @@ namespace zn
     Logger& m_logger;
     std::string m_source;
     Program m_program;
-    VM m_vm;
+    VM m_vm { m_program };
+    SymTable m_sym;
+    Zarn m_zarn {m_sym, m_vm};
   };
 }
 
diff --git a/src/NativeFunction.cpp b/src/NativeFunction.cpp
new file mode 100644
index 0000000..08cfba4
--- /dev/null
+++ b/src/NativeFunction.cpp
@@ -0,0 +1,24 @@
+#include "NativeFunction.hpp"
+
+namespace zn
+{
+  /*explicit*/ NativeFunction::NativeFunction(std::shared_ptr<Prototype>
+                                              prototype,
+                                              native_fn_t body)
+    : m_prototype { prototype }
+    , m_body { body }
+  {
+  }
+
+  /*virtual*/ NativeFunction::~NativeFunction()
+  {
+  }
+
+  std::shared_ptr<Constant>
+  NativeFunction::call(std::vector<std::shared_ptr<Constant>> const& args)
+  {
+    assert(m_body);
+    return m_body(args);
+  }
+
+}
diff --git a/src/NativeFunction.hpp b/src/NativeFunction.hpp
new file mode 100644
index 0000000..e7a719e
--- /dev/null
+++ b/src/NativeFunction.hpp
@@ -0,0 +1,30 @@
+#ifndef zn_NATIVEFUNCTION_HPP
+#define zn_NATIVEFUNCTION_HPP
+
+#include "common.hpp"
+#include "Prototype.hpp"
+
+namespace zn
+{
+  class Constant;
+  using const_t = std::shared_ptr<Constant>;
+  using native_fn_t = std::function<const_t(std::vector<const_t>)>;
+  class NativeFunction
+  {
+  public:
+    explicit NativeFunction(std::shared_ptr<Prototype> prototype,
+                            native_fn_t body);
+    virtual ~NativeFunction();
+
+    std::shared_ptr<Prototype> prototype() const { return m_prototype; }
+
+    std::shared_ptr<Constant>
+    call(std::vector<std::shared_ptr<Constant>> const& args);
+
+  private:
+    std::shared_ptr<Prototype> m_prototype;
+    native_fn_t m_body;
+  };
+}
+
+#endif
diff --git a/src/Node.hpp b/src/Node.hpp
index 8f45838..3a90164 100644
--- a/src/Node.hpp
+++ b/src/Node.hpp
@@ -4,9 +4,13 @@
 #include "common.hpp"
 #include "Loc.hpp"
 
-#define NODE_TYPES(G) \
-  G(NODE_MODULE),     \
-    G(NODE_INT)
+#define NODE_TYPES(G)                           \
+  G(NODE_MODULE),                               \
+    G(NODE_INT),                                \
+    G(NODE_OPAR),                               \
+    G(NODE_CPAR),                               \
+    G(NODE_IDENT),                              \
+    G(NODE_CALL),
 
 namespace zn
 {
diff --git a/src/Parser.cpp b/src/Parser.cpp
index 4223373..713639b 100644
--- a/src/Parser.cpp
+++ b/src/Parser.cpp
@@ -77,6 +77,11 @@ namespace zn
 
   std::shared_ptr<Node> Parser::parse_module()
   {
+    if (m_tokens.empty())
+      {
+        return std::make_shared<Node>(NODE_MODULE, "", Loc {""});
+      }
+
     auto node = mk_node(NODE_MODULE);
 
     while (m_cursor < m_tokens.size())
@@ -89,11 +94,17 @@ namespace zn
 
   std::shared_ptr<Node> Parser::parse_expr()
   {
-    if (type_is(NODE_INT))
+    if (type_is(NODE_INT)
+        || type_is(NODE_IDENT))
       {
         return consume();
       }
 
+    if (type_is(NODE_OPAR))
+      {
+        return parse_call();
+      }
+
     std::stringstream ss;
     ss << "unknown expression '"
        << m_tokens[m_cursor]->string()
@@ -104,4 +115,20 @@ namespace zn
                                ss.str());
     abort();
   }
+
+  std::shared_ptr<Node> Parser::parse_call()
+  {
+    consume(NODE_OPAR);
+    auto node = mk_node(NODE_CALL);
+    node->add_child(consume(NODE_IDENT));
+
+    while (!type_is(NODE_CPAR))
+      {
+        node->add_child(parse_expr());
+      }
+
+    consume(NODE_CPAR);
+
+    return node;
+  }
 }
diff --git a/src/Parser.hpp b/src/Parser.hpp
index bce17ed..11bb5e7 100644
--- a/src/Parser.hpp
+++ b/src/Parser.hpp
@@ -31,6 +31,7 @@ namespace zn
 
     std::shared_ptr<Node> parse_module();
     std::shared_ptr<Node> parse_expr();
+    std::shared_ptr<Node> parse_call();
 
   };
 }
diff --git a/src/Program.hpp b/src/Program.hpp
index 4f86523..8fb9fe6 100644
--- a/src/Program.hpp
+++ b/src/Program.hpp
@@ -6,9 +6,14 @@
 
 #define NO_PARAM (-1)
 
-#define OPCODES(G) \
+#define OPCODES(G)                              \
   G(OPCODE_LOAD_CONST),                         \
-    G(OPCODE_POP)
+    G(OPCODE_LOAD_GLOBAL),                      \
+    G(OPCODE_STORE_GLOBAL),                     \
+    G(OPCODE_LOAD_LOCAL),                        \
+    G(OPCODE_STORE_LOCAL),                       \
+    G(OPCODE_POP),                              \
+    G(OPCODE_CALL_NATIVE),                      \
 
 namespace zn
 {
diff --git a/src/Prototype.cpp b/src/Prototype.cpp
new file mode 100644
index 0000000..a91e366
--- /dev/null
+++ b/src/Prototype.cpp
@@ -0,0 +1,105 @@
+#include "Prototype.hpp"
+
+namespace zn
+{
+  /*explicit*/ Prototype::Prototype()
+  {
+  }
+
+  /*virtual*/ Prototype::~Prototype()
+  {
+  }
+
+  TypeSlot Prototype::get_param(size_t index) const
+  {
+    assert(index < m_params.size());
+    return m_params[index];
+  }
+
+  std::shared_ptr<Prototype> Prototype::param(TypeSlot param)
+  {
+    m_params.push_back(param);
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::param(Type param)
+  {
+    TypeSlot slot;
+    slot.type = param;
+    m_params.push_back(slot);
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::param_any()
+  {
+    TypeSlot slot;
+    slot.type = std::nullopt;
+    slot.tag = TAG_ANY;
+    m_params.push_back(slot);
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::param_variadic()
+  {
+    TypeSlot slot;
+    slot.type = std::nullopt;
+    slot.tag = TAG_VARIADIC;
+    m_params.push_back(slot);
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::ret(TypeSlot ret)
+  {
+    m_return = ret;
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::ret(Type ret)
+  {
+    TypeSlot slot;
+    slot.type = ret;
+    m_return = slot;
+    return shared_from_this();
+  }
+
+  std::shared_ptr<Prototype> Prototype::ret_any()
+  {
+    TypeSlot slot;
+    slot.type = std::nullopt;
+    slot.tag = TAG_ANY;
+    m_return = slot;
+    return shared_from_this();
+  }
+
+  std::string Prototype::string() const
+  {
+    std::stringstream ss;
+
+    std::string sep;
+
+    for (auto param: m_params)
+      {
+        if (param.tag == TAG_ANY)
+          {
+            ss << sep << "ANY";
+          }
+        else
+          {
+            ss << sep << (TypeStr[*param.type] + strlen("TYPE_"));
+          }
+
+        sep = ", ";
+      }
+
+    if (m_return.tag == TAG_ANY)
+      {
+        ss << " -> " << "ANY";
+      }
+    else
+      {
+        ss << " -> " << (TypeStr[*m_return.type] + strlen("TYPE_"));
+      }
+
+    return ss.str();
+  }
+}
diff --git a/src/Prototype.hpp b/src/Prototype.hpp
new file mode 100644
index 0000000..1f7dc94
--- /dev/null
+++ b/src/Prototype.hpp
@@ -0,0 +1,50 @@
+#ifndef zn_PROTOTYPE_HPP
+#define zn_PROTOTYPE_HPP
+
+#include "common.hpp"
+#include "types.hpp"
+#include <memory>
+
+#define TYPE_TAGS(G)                            \
+  G(TAG_NONE),                                  \
+    G(TAG_ANY),                                 \
+    G(TAG_VARIADIC)
+
+namespace zn
+{
+  ZN_MK_ENUM(Tag, TYPE_TAGS);
+
+  struct TypeSlot {
+    std::optional<Type> type = TYPE_NIL;
+    Tag tag = TAG_NONE;
+  };
+
+  class Prototype: public std::enable_shared_from_this<Prototype>
+  {
+  public:
+    explicit Prototype();
+    virtual ~Prototype();
+
+    TypeSlot get_ret() const { return m_return; }
+    size_t get_param_count() const { return m_params.size(); }
+
+    TypeSlot get_param(size_t index) const;
+
+    std::shared_ptr<Prototype> param(TypeSlot param);
+    std::shared_ptr<Prototype> param(Type param);
+    std::shared_ptr<Prototype> param_any();
+    std::shared_ptr<Prototype> param_variadic();
+
+    std::shared_ptr<Prototype> ret(TypeSlot ret);
+    std::shared_ptr<Prototype> ret(Type ret);
+    std::shared_ptr<Prototype> ret_any();
+
+    std::string string() const;
+
+  private:
+    std::vector<TypeSlot> m_params;
+    TypeSlot m_return;
+  };
+}
+
+#endif
diff --git a/src/StaticPass.cpp b/src/StaticPass.cpp
new file mode 100644
index 0000000..8f713f8
--- /dev/null
+++ b/src/StaticPass.cpp
@@ -0,0 +1,114 @@
+#include "StaticPass.hpp"
+
+namespace zn
+{
+  /*explicit*/ StaticPass::StaticPass(Logger& logger, SymTable& sym)
+    : m_logger { logger }
+    , m_sym { sym }
+  {
+  }
+
+  /*virtual*/ StaticPass::~StaticPass()
+  {
+  }
+
+  TypeSlot StaticPass::execute(Node const& node)
+  {
+    switch (node.type())
+      {
+      case NODE_MODULE: {
+        for (size_t i=0; i<node.size(); i++)
+          {
+            execute(*node.child_at(i));
+          }
+
+        return TypeSlot {TYPE_NIL};
+      } break;
+
+      case NODE_CALL: {
+        std::string ident = node.child_at(0)->repr();
+        auto sym = m_sym.find(ident);
+
+        if (sym == std::nullopt)
+          {
+            m_logger.log<static_error>(LOG_ERROR,
+                                       node.loc(),
+                                       "cannot call unknown function '"
+                                       + ident
+                                       + "'");
+          }
+
+        auto proto = sym->prototype;
+        assert(proto);
+
+        if (proto->get_param_count() != node.size() - 1
+            && proto->get_param(proto->get_param_count() - 1).tag
+            != TAG_VARIADIC)
+          {
+            std::stringstream ss;
+            ss << "type mismatch, expected '"
+               << proto->get_param_count()
+               << "' parameters, got '"
+               << (node.size() - 1)
+               << "'";
+
+            m_logger.log<static_error>(LOG_ERROR, node.loc(), ss.str());
+          }
+
+        size_t j = 0;
+
+        for (size_t i=1; i<node.size(); i++)
+          {
+            auto ty = execute(*node.child_at(i));
+
+            if ((ty.tag != proto->get_param(j).tag
+                 || ty.type != proto->get_param(j).type)
+                && ty.tag != TAG_ANY
+                && proto->get_param(j).tag != TAG_ANY)
+              {
+                type_mismatch(node.loc(), proto->get_param(j), ty);
+              }
+
+            if (j + 1 < proto->get_param_count()
+                && proto->get_param(j + 1).tag != TAG_VARIADIC)
+              {
+                j++;
+              }
+          }
+
+        return proto->get_ret();
+      } break;
+
+      case NODE_INT: {
+        return TypeSlot {TYPE_INT};
+      } break;
+
+      default: {
+        std::cerr << "cannot static check node '"
+                  << NodeTypeStr[node.type()]
+                  << "'"
+                  << std::endl;
+        abort();
+      } break;
+      }
+  }
+
+  void StaticPass::type_mismatch(Loc const& loc,
+                                 TypeSlot lhs,
+                                 TypeSlot rhs)
+  {
+    auto to_s = [](TypeSlot s){
+      if (s.tag == TAG_ANY) { return "ANY"; }
+      return TypeStr[*s.type] + strlen("TYPE_");
+    };
+
+    std::stringstream ss;
+    ss << "type mismatch, expected '"
+       << to_s(lhs)
+       << "', got '"
+       << to_s(rhs)
+       << "'";
+
+    m_logger.log<static_error>(LOG_ERROR, loc, ss.str());
+  }
+}
diff --git a/src/StaticPass.hpp b/src/StaticPass.hpp
new file mode 100644
index 0000000..1472b19
--- /dev/null
+++ b/src/StaticPass.hpp
@@ -0,0 +1,30 @@
+#ifndef zn_STATICPASS_HPP
+#define zn_STATICPASS_HPP
+
+#include "common.hpp"
+#include "Node.hpp"
+#include "Logger.hpp"
+#include "SymTable.hpp"
+
+namespace zn
+{
+  ZN_ERROR(static_error);
+
+  class StaticPass
+  {
+  public:
+    explicit StaticPass(Logger& logger, SymTable& sym);
+    virtual ~StaticPass();
+
+    TypeSlot execute(Node const& node);
+  private:
+    Logger& m_logger;
+    SymTable& m_sym;
+
+    void type_mismatch(Loc const& loc,
+                       TypeSlot lhs,
+                       TypeSlot rhs);
+  };
+}
+
+#endif
diff --git a/src/SymTable.cpp b/src/SymTable.cpp
new file mode 100644
index 0000000..170bad0
--- /dev/null
+++ b/src/SymTable.cpp
@@ -0,0 +1,37 @@
+#include "SymTable.hpp"
+
+namespace zn
+{
+  /*explicit*/ SymTable::SymTable()
+  {
+  }
+
+  /*virtual*/ SymTable::~SymTable()
+  {
+  }
+
+  void SymTable::declare(std::string const& name, size_t addr)
+  {
+    m_syms.push_back(Sym {name, addr});
+  }
+
+  void SymTable::declare_function(std::string const& name,
+                                  size_t addr,
+                                  std::shared_ptr<Prototype> prototype)
+  {
+    m_syms.push_back(Sym {name, addr, prototype});
+  }
+
+  std::optional<Sym> SymTable::find(std::string const& name)
+  {
+    for (size_t i=0; i<m_syms.size(); i++)
+      {
+        if (name == m_syms[i].name)
+          {
+            return m_syms[i];
+          }
+      }
+
+    return std::nullopt;
+  }
+}
diff --git a/src/SymTable.hpp b/src/SymTable.hpp
new file mode 100644
index 0000000..6a0d6c7
--- /dev/null
+++ b/src/SymTable.hpp
@@ -0,0 +1,34 @@
+#ifndef zn_SYMTABLE_HPP
+#define zn_SYMTABLE_HPP
+
+#include "common.hpp"
+#include "Prototype.hpp"
+
+namespace zn
+{
+  struct Sym {
+    std::string name;
+    size_t addr;
+    std::shared_ptr<Prototype> prototype = nullptr;
+  };
+
+  class SymTable
+  {
+  public:
+    explicit SymTable();
+    virtual ~SymTable();
+
+    void declare(std::string const& name, size_t addr);
+
+    void declare_function(std::string const& name,
+                          size_t addr,
+                          std::shared_ptr<Prototype> prototype);
+
+    std::optional<Sym> find(std::string const& name);
+
+  private:
+    std::vector<Sym> m_syms;
+  };
+}
+
+#endif
diff --git a/src/VM.cpp b/src/VM.cpp
index 27aa3ec..a6c92f4 100644
--- a/src/VM.cpp
+++ b/src/VM.cpp
@@ -3,8 +3,11 @@
 
 namespace zn
 {
-  /*explicit*/ VM::VM()
+  /*explicit*/ VM::VM(Program& program)
   {
+    m_pc = 0;
+    Frame f = {program, {}};
+    m_frames.push_back(f);
   }
 
   /*virtual*/ VM::~VM()
@@ -14,16 +17,15 @@ namespace zn
   void VM::execute(Program& program)
   {
     m_pc = 0;
-    m_frames.push_back(Frame {program});
 
     while (m_pc < program.size())
       {
         auto instr = program.instr(m_pc);
-        execute(instr.opcode, instr.param);
+        execute(program, instr.opcode, instr.param);
       }
   }
 
-  void VM::execute(Opcode opcode, int param)
+  void VM::execute(Program& program, Opcode opcode, int param)
   {
     switch (opcode)
       {
@@ -32,11 +34,41 @@ namespace zn
         m_pc++;
       } break;
 
+      case OPCODE_LOAD_LOCAL: {
+        auto constant = frame().locals[to_vm_addr(param)];
+        push(program.add_constant(constant));
+        m_pc++;
+      } break;
+
       case OPCODE_POP: {
         pop();
         m_pc++;
       } break;
 
+      case OPCODE_CALL_NATIVE: {
+        std::vector<std::shared_ptr<Constant>> args;
+
+        for (int i=0; i<param; i++)
+          {
+            size_t addr = pop();
+            args.insert(std::begin(args),
+                        frame().program.constant(addr));
+          }
+
+        auto fun_ref = m_frames.back().program.constant(pop());
+        int ref = std::get<int>(*fun_ref->value());
+
+        auto fun = std::get<std::shared_ptr<NativeFunction>>
+          (m_globals[ref]);
+        assert(fun);
+
+        auto result = fun->call(args);
+        int addr = m_frames.back().program.add_constant(result);
+        push(addr);
+
+        m_pc++;
+      } break;
+
       default: {
         std::cerr << "cannot execute opcode '"
                   << OpcodeStr[opcode]
@@ -63,6 +95,52 @@ namespace zn
     return ss.str();
   }
 
+  size_t VM::store_local(int index, std::shared_ptr<Constant> constant)
+  {
+    frame().locals.push_back(constant);
+    size_t addr = frame().locals.size() - 1;
+    m_addr_mapping[index] = addr;
+    return addr;
+  }
+
+  std::shared_ptr<Constant> VM::load_local(int index) const
+  {
+    size_t addr = to_vm_addr(index);
+    assert(addr < m_frames.back().locals.size());
+    return m_frames.back().locals[addr];
+  }
+
+  size_t VM::store_global(global_var_t var)
+  {
+    m_globals.push_back(var);
+    return m_globals.size() - 1;
+  }
+
+  size_t VM::to_vm_addr(int user_addr) const
+  {
+    return m_addr_mapping.at(user_addr);
+  }
+
+  int VM::to_user_addr(size_t vm_addr) const
+  {
+    for (auto const& entry: m_addr_mapping)
+      {
+        if (entry.second == vm_addr)
+          {
+            return entry.first;
+          }
+      }
+
+    std::cerr << "cannot find user addr of '"
+              << vm_addr << "'" << std::endl;
+    abort();
+  }
+
+  Frame& VM::frame()
+  {
+    return m_frames.back();
+  }
+
   void VM::push(int value)
   {
     m_stack.push_back(value);
diff --git a/src/VM.hpp b/src/VM.hpp
index 63cd995..54b64d6 100644
--- a/src/VM.hpp
+++ b/src/VM.hpp
@@ -3,29 +3,44 @@
 
 #include "common.hpp"
 #include "Program.hpp"
+#include "src/NativeFunction.hpp"
 
 namespace zn
 {
   struct Frame {
     Program& program;
+    std::vector<std::shared_ptr<Constant>> locals;
   };
 
+  using global_var_t = std::variant<std::shared_ptr<NativeFunction>>;
+
   class VM
   {
   public:
-    explicit VM();
+    explicit VM(Program& program);
     virtual ~VM();
 
     void execute(Program& program);
-    void execute(Opcode opcode, int param);
+    void execute(Program& program, Opcode opcode, int param);
 
     std::string string() const;
 
+    size_t store_local(int index, std::shared_ptr<Constant> constant);
+    std::shared_ptr<Constant> load_local(int index) const;
+
+    size_t store_global(global_var_t var);
+
+    size_t to_vm_addr(int user_addr) const;
+    int to_user_addr(size_t vm_addr) const;
+
   private:
     std::vector<Frame> m_frames;
     std::vector<int> m_stack;
+    std::vector<global_var_t> m_globals;
+    std::unordered_map<int, size_t> m_addr_mapping;
     size_t m_pc = 0;
 
+    Frame& frame();
     void push(int value);
     int pop();
   };
diff --git a/src/Zarn.cpp b/src/Zarn.cpp
new file mode 100644
index 0000000..0e50f71
--- /dev/null
+++ b/src/Zarn.cpp
@@ -0,0 +1,54 @@
+#include <dlfcn.h>
+#include "config.hpp"
+#include "Zarn.hpp"
+
+namespace zn
+{
+  /*explicit*/ Zarn::Zarn(SymTable& sym, VM& vm)
+    : m_sym { sym }
+    , m_vm { vm }
+  {
+  }
+
+  /*virtual*/ Zarn::~Zarn()
+  {
+    for (void* handler: m_handlers)
+      {
+        // dlclose(handler);
+      }
+
+    m_handlers.clear();
+  }
+
+  void Zarn::register_function(std::string const& name,
+                               std::shared_ptr<Prototype> prototype,
+                               native_fn_t body)
+  {
+    auto func = std::make_shared<NativeFunction>(prototype, body);
+    int addr = m_vm.store_global(func);
+    m_sym.declare_function(name, addr, prototype);
+
+    // auto ref = std::make_shared<Constant>(TYPE_REF, addr);
+    // m_vm.store_local(0, ref);
+    // m_sym.declare_function(name, 0, prototype);
+  }
+
+  void Zarn::load_std_library()
+  {
+    load_library(ZN_LIBDIR / "libzarn-std.so");
+  }
+
+  void Zarn::load_library(std::filesystem::path lib_path)
+  {
+    void* handler = dlopen(lib_path.string().c_str(), RTLD_LAZY);
+    assert(handler);
+    m_handlers.push_back(handler);
+
+
+    typedef void(*fun)(Zarn&);
+    fun f = (fun) dlsym(handler, "lib");
+    assert(f);
+
+    f(*this);
+  }
+}
diff --git a/src/Zarn.hpp b/src/Zarn.hpp
new file mode 100644
index 0000000..ff7a8e0
--- /dev/null
+++ b/src/Zarn.hpp
@@ -0,0 +1,29 @@
+#ifndef zn_ZARN_HPP
+#define zn_ZARN_HPP
+
+#include "common.hpp"
+#include "SymTable.hpp"
+#include "VM.hpp"
+
+namespace zn
+{
+  class Zarn
+  {
+  public:
+    explicit Zarn(SymTable& sym, VM& vm);
+    virtual ~Zarn();
+
+    void register_function(std::string const& name,
+                           std::shared_ptr<Prototype> prototype,
+                           native_fn_t body);
+
+    void load_std_library();
+    void load_library(std::filesystem::path lib_path);
+  private:
+    SymTable& m_sym;
+    VM& m_vm;
+    std::vector<void*> m_handlers;
+  };
+}
+
+#endif
diff --git a/src/config.in.hpp b/src/config.in.hpp
new file mode 100644
index 0000000..5e2c324
--- /dev/null
+++ b/src/config.in.hpp
@@ -0,0 +1,8 @@
+#ifndef zn_CONFIG_HPP
+#define zn_CONFIG_HPP
+
+#include <filesystem>
+
+#define ZN_VERSION "@version@"
+#define ZN_LIBDIR std::filesystem::path("@libdir@")
+#endif
diff --git a/src/types.hpp b/src/types.hpp
new file mode 100644
index 0000000..1039bdf
--- /dev/null
+++ b/src/types.hpp
@@ -0,0 +1,16 @@
+#ifndef zn_TYPES_HPP
+#define zn_TYPES_HPP
+
+#include "common.hpp"
+
+#define TYPES(G) \
+  G(TYPE_NIL),   \
+    G(TYPE_INT), \
+    G(TYPE_REF)
+
+namespace zn
+{
+  ZN_MK_ENUM(Type, TYPES);
+}
+
+#endif
diff --git a/tests/Lexer.cpp b/tests/Lexer.cpp
index 0219f8c..1413b7f 100644
--- a/tests/Lexer.cpp
+++ b/tests/Lexer.cpp
@@ -21,12 +21,6 @@ protected:
   zn::Lexer m_lexer { m_logger, m_loc };
 };
 
-TEST_CASE_METHOD(LexerTest, "Lexer_unknown_text")
-{
-  m_lexer.scan(" §§§ ");
-  REQUIRE_THROWS_AS(m_lexer.try_next(), zn::lex_error);
-}
-
 TEST_CASE_METHOD(LexerTest, "Lexer_int")
 {
   m_lexer.scan(" 3 -2 167 ");
@@ -36,3 +30,14 @@ TEST_CASE_METHOD(LexerTest, "Lexer_int")
   test_next(m_lexer, "INT[167]");
   REQUIRE(nullptr == m_lexer.try_next());
 }
+
+TEST_CASE_METHOD(LexerTest, "Lexer_call")
+{
+  m_lexer.scan(" (hello world) ");
+
+  test_next(m_lexer, "OPAR");
+  test_next(m_lexer, "IDENT[hello]");
+  test_next(m_lexer, "IDENT[world]");
+  test_next(m_lexer, "CPAR");
+  REQUIRE(nullptr == m_lexer.try_next());
+}
diff --git a/tests/Parser.cpp b/tests/Parser.cpp
index 6024cff..4860342 100644
--- a/tests/Parser.cpp
+++ b/tests/Parser.cpp
@@ -29,3 +29,9 @@ TEST_CASE_METHOD(ParserTest, "Parser_int")
 {
   test_parse("MODULE(INT[37])", " 37");
 }
+
+TEST_CASE_METHOD(ParserTest, "Parser_call")
+{
+  test_parse("MODULE(CALL(IDENT[hello],INT[1],INT[2],IDENT[world]))",
+             " (hello 1 2 world)");
+}