diff --git a/Makefile b/Makefile
index f2abb399..59f3ada0 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ build:
 	cd src; \
 	yacc -d parse.y; \
 	lex scan.l
-	 $(CC) -Wall -o bin/picrin -I./include -lreadline src/main.c src/state.c src/gc.c src/pair.c src/port.c src/symbol.c src/value.c src/y.tab.c src/lex.yy.c src/bool.c src/vm.c src/init.c src/number.c src/time.c
+	 $(CC) -Wall -o bin/picrin -I./include -lreadline src/main.c src/state.c src/gc.c src/pair.c src/port.c src/symbol.c src/value.c src/y.tab.c src/lex.yy.c src/bool.c src/vm.c src/init.c src/number.c src/time.c src/codegen.c
 
 clean:
 	rm -f src/y.tab.c src/y.tab.h src/lex.yy.c
diff --git a/src/codegen.c b/src/codegen.c
new file mode 100644
index 00000000..38993077
--- /dev/null
+++ b/src/codegen.c
@@ -0,0 +1,450 @@
+#include <stdio.h>
+
+#include "picrin.h"
+#include "picrin/pair.h"
+#include "picrin/irep.h"
+#include "picrin/proc.h"
+
+static bool
+env_lookup(pic_state *pic, pic_value sym, struct pic_env *env, int *depth, int *idx)
+{
+  pic_value v;
+  int d = 0;
+
+ enter:
+
+  v = pic_assq(pic, sym, env->assoc);
+  if (! pic_nil_p(v)) {
+    if (env->parent == NULL) {		/* global */
+      *depth = -1;
+    }
+    else {			/* non-global */
+      *depth = d;
+    }
+    *idx = (int)pic_float(pic_pair_ptr(v)->cdr);
+    return true;
+  }
+  if (env->parent) {
+    env = env->parent;
+    ++d;
+    goto enter;
+  }
+  return false;
+}
+
+static int
+env_global_define(pic_state *pic, pic_value sym)
+{
+  pic_value f;
+  int d, idx;
+
+  if (env_lookup(pic, sym, pic->global_env, &d, &idx)) {
+    return idx;
+  }
+
+  idx = pic->glen++;
+  f = pic_float_value(idx);
+  pic->global_env->assoc = pic_acons(pic, sym, f, pic->global_env->assoc);
+
+  return idx;
+}
+
+static struct pic_env *
+env_new(pic_state *pic, pic_value args, struct pic_env *env)
+{
+  struct pic_env *inner_env;
+  pic_value v, f;
+  int i;
+
+  inner_env = (struct pic_env *)pic_alloc(pic, sizeof(struct pic_env));
+  inner_env->assoc = pic_nil_value();
+  inner_env->parent = env;
+
+  i = -1;
+  for (v = args; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
+    pic_value sym = pic_car(pic, v);
+
+    f = pic_float_value(i--);
+    inner_env->assoc = pic_acons(pic, sym, f, inner_env->assoc);
+  }
+
+  return inner_env;
+}
+
+void
+pic_defun(pic_state *pic, const char *name, pic_func_t cfunc)
+{
+  struct pic_proc *proc;
+  int idx;
+
+  proc = (struct pic_proc *)pic_obj_alloc(pic, sizeof(struct pic_proc), PIC_TT_PROC);
+  proc->cfunc_p = true;
+  proc->u.cfunc = cfunc;
+  idx = env_global_define(pic, pic_intern_cstr(pic, name));
+  pic->globals[idx] = pic_obj_value(proc);
+}
+
+static void
+print_irep(pic_state *pic, struct pic_irep *irep)
+{
+  int i;
+
+  printf("## irep %p [clen = %zd, ccapa = %zd]\n", irep, irep->clen, irep->ccapa);
+  for (i = 0; i < irep->clen; ++i) {
+    switch (irep->code[i].insn) {
+    case OP_POP:
+      puts("OP_POP");
+      break;
+    case OP_PUSHNIL:
+      puts("OP_PUSHNIL");
+      break;
+    case OP_PUSHTRUE:
+      puts("OP_PUSHTRUE");
+      break;
+    case OP_PUSHFALSE:
+      puts("OP_PUSHFALSE");
+      break;
+    case OP_PUSHNUM:
+      printf("OP_PUSHNUM\t%g\n", irep->code[i].u.f);
+      break;
+    case OP_GREF:
+      printf("OP_GREF\t%i\n", irep->code[i].u.i);
+      break;
+    case OP_GSET:
+      printf("OP_GSET\t%i\n", irep->code[i].u.i);
+      break;
+    case OP_LREF:
+      printf("OP_LREF\t%d\n", irep->code[i].u.i);
+      break;
+    case OP_JMP:
+      printf("OP_JMP\t%d\n", irep->code[i].u.i);
+      break;
+    case OP_JMPIF:
+      printf("OP_JMPIF\t%d\n", irep->code[i].u.i);
+      break;
+    case OP_CALL:
+      printf("OP_CALL\t%d\n", irep->code[i].u.i);
+      break;
+    case OP_RET:
+      puts("OP_RET");
+      break;
+    case OP_LAMBDA:
+      printf("OP_LAMBDA\t%d\n", irep->code[i].u.i);
+      break;
+    case OP_CONS:
+      puts("OP_CONS");
+      break;
+    case OP_CAR:
+      puts("OP_CAR");
+      break;
+    case OP_NILP:
+      puts("OP_NILP");
+      break;
+    case OP_CDR:
+      puts("OP_CDR");
+      break;
+    case OP_ADD:
+      puts("OP_ADD");
+      break;
+    case OP_SUB:
+      puts("OP_SUB");
+      break;
+    case OP_MUL:
+      puts("OP_MUL");
+      break;
+    case OP_DIV:
+      puts("OP_DIV");
+      break;
+    case OP_STOP:
+      puts("OP_STOP");
+      break;
+    }
+  }
+}
+
+static struct pic_irep *
+new_irep(pic_state *pic)
+{
+  struct pic_irep *irep;
+
+  irep = (struct pic_irep *)pic_alloc(pic, sizeof(struct pic_irep));
+  irep->code = (struct pic_code *)pic_alloc(pic, sizeof(struct pic_code) * 1024);
+  irep->clen = 0;
+  irep->ccapa = 1024;
+  return irep;
+}
+
+static void pic_gen_call(pic_state *, struct pic_irep *, pic_value, struct pic_env *);
+static struct pic_irep *pic_gen_lambda(pic_state *, pic_value, struct pic_env *);
+
+static void
+pic_gen(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *env)
+{
+  pic_value sDEFINE, sLAMBDA, sIF, sBEGIN;
+  pic_value sCONS, sCAR, sCDR, sNILP;
+  pic_value sADD, sSUB, sMUL, sDIV;
+
+  sDEFINE = pic->sDEFINE;
+  sLAMBDA = pic->sLAMBDA;
+  sIF = pic->sIF;
+  sBEGIN = pic->sBEGIN;
+  sCONS = pic->sCONS;
+  sCAR = pic->sCAR;
+  sCDR = pic->sCDR;
+  sNILP = pic->sNILP;
+  sADD = pic->sADD;
+  sSUB = pic->sSUB;
+  sMUL = pic->sMUL;
+  sDIV = pic->sDIV;
+
+  switch (pic_type(obj)) {
+  case PIC_TT_SYMBOL: {
+    bool b;
+    int depth, idx;
+
+    b = env_lookup(pic, obj, env, &depth, &idx);
+    if (! b) {
+      pic_raise(pic, "unbound variable");
+    }
+
+    if (depth == -1) {		/* global */
+      irep->code[irep->clen].insn = OP_GREF;
+      irep->code[irep->clen].u.i = idx;
+      irep->clen++;
+    }
+    else if (depth == 0) {	/* local */
+      irep->code[irep->clen].insn = OP_LREF;
+      irep->code[irep->clen].u.i = idx;
+      irep->clen++;
+    }
+    else {			/* nonlocal */
+      pic_raise(pic, "reference to closed variable not supported");
+    }
+    break;
+  }
+  case PIC_TT_PAIR: {
+    pic_value proc;
+
+    proc = pic_car(pic, obj);
+    if (pic_eq_p(pic, proc, sDEFINE)) {
+      int idx;
+
+      idx = env_global_define(pic, pic_car(pic, pic_cdr(pic, obj)));
+
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+
+      irep->code[irep->clen].insn = OP_GSET;
+      irep->code[irep->clen].u.i = idx;
+      irep->clen++;
+      irep->code[irep->clen].insn = OP_PUSHFALSE;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sLAMBDA)) {
+      irep->code[irep->clen].insn = OP_LAMBDA;
+      irep->code[irep->clen].u.i = pic->ilen;
+      irep->clen++;
+
+      pic->irep[pic->ilen++] = pic_gen_lambda(pic, obj, env);
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sIF)) {
+      int s,t;
+
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+
+      irep->code[irep->clen].insn = OP_JMPIF;
+      s = irep->clen++;
+
+      /* if false branch */
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, pic_cdr(pic, obj)))), env);
+      irep->code[irep->clen].insn = OP_JMP;
+      t = irep->clen++;
+
+      irep->code[s].u.i = irep->clen - s;
+
+      /* if true branch */
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      irep->code[t].u.i = irep->clen - t;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sBEGIN)) {
+      pic_value v, seq;
+
+      seq = pic_cdr(pic, obj);
+      for (v = seq; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
+	pic_gen(pic, irep, pic_car(pic, v), env);
+	irep->code[irep->clen].insn = OP_POP;
+	irep->clen++;
+      }
+      irep->clen--;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sCONS)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_CONS;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sCAR)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_CAR;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sCDR)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_CDR;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sNILP)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_NILP;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sADD)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_ADD;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sSUB)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_SUB;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sMUL)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_MUL;
+      irep->clen++;
+      break;
+    }
+    else if (pic_eq_p(pic, proc, sDIV)) {
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
+      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
+      irep->code[irep->clen].insn = OP_DIV;
+      irep->clen++;
+      break;
+    }
+    else {
+      pic_gen_call(pic, irep, obj, env);
+      break;
+    }
+  }
+  case PIC_TT_BOOL: {
+    if (pic_true_p(obj)) {
+      irep->code[irep->clen].insn = OP_PUSHTRUE;
+    }
+    else {
+      irep->code[irep->clen].insn = OP_PUSHFALSE;
+    }
+    irep->clen++;
+    break;
+  }
+  case PIC_TT_FLOAT: {
+    irep->code[irep->clen].insn = OP_PUSHNUM;
+    irep->code[irep->clen].u.f = pic_float(obj);
+    irep->clen++;
+    break;
+  }
+  case PIC_TT_NIL: {
+    irep->code[irep->clen].insn = OP_PUSHNIL;
+    irep->clen++;
+    break;
+  }
+  case PIC_TT_PROC:
+  case PIC_TT_UNDEF:
+  case PIC_TT_PORT: {
+    pic_raise(pic, "invalid expression given");
+  }
+  }
+}
+
+static pic_value
+reverse(pic_state *pic, pic_value list, pic_value acc)
+{
+  if (pic_nil_p(list))
+    return acc;
+  return reverse(pic, pic_cdr(pic, list), pic_cons(pic, pic_car(pic, list), acc));
+}
+
+static void
+pic_gen_call(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *env)
+{
+  pic_value seq;
+  int i = 0;
+
+  seq = reverse(pic, obj, pic_nil_value());
+  for (; ! pic_nil_p(seq); seq = pic_cdr(pic, seq)) {
+    pic_value v;
+
+    v = pic_car(pic, seq);
+    pic_gen(pic, irep, v, env);
+    ++i;
+  }
+  irep->code[irep->clen].insn = OP_CALL;
+  irep->code[irep->clen].u.i = i;
+  irep->clen++;
+}
+
+static struct pic_irep *
+pic_gen_lambda(pic_state *pic, pic_value obj, struct pic_env *env)
+{
+  struct pic_env *inner_env;
+  pic_value args, body, v;
+  struct pic_irep *irep;
+
+  irep = new_irep(pic);
+
+  /* arguments */
+  args = pic_car(pic, pic_cdr(pic, obj));
+  inner_env = env_new(pic, args, env);
+
+  /* body */
+  body = pic_cdr(pic, pic_cdr(pic, obj));
+  for (v = body; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
+    pic_gen(pic, irep, pic_car(pic, v), inner_env);
+    irep->code[irep->clen].insn = OP_POP;
+    irep->clen++;
+  }
+  irep->clen--;
+  irep->code[irep->clen].insn = OP_RET;
+  irep->clen++;
+  pic_free(pic, inner_env);
+
+#if VM_DEBUG
+  printf("LAMBDA_%zd:\n", pic->ilen);
+  print_irep(pic, irep);
+  puts("");
+#endif
+
+  return irep;
+}
+
+struct pic_proc *
+pic_codegen(pic_state *pic, pic_value obj, struct pic_env *env)
+{
+  struct pic_proc *proc;
+  struct pic_irep *irep;
+
+  proc = (struct pic_proc *)pic_obj_alloc(pic, sizeof(struct pic_proc), PIC_TT_PROC);
+  proc->cfunc_p = false;
+  proc->u.irep = irep = new_irep(pic);
+
+  pic_gen(pic, irep, obj, env);
+  irep->code[irep->clen].insn = OP_STOP;
+  irep->clen++;
+
+#if VM_DEBUG
+  print_irep(pic, irep);
+#endif
+
+  return proc;
+}
diff --git a/src/vm.c b/src/vm.c
index d090a796..01ba27cd 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -3,88 +3,9 @@
 #include <stdarg.h>
 
 #include "picrin.h"
-#include "picrin/irep.h"
-#include "picrin/proc.h"
 #include "picrin/pair.h"
-
-static bool
-env_lookup(pic_state *pic, pic_value sym, struct pic_env *env, int *depth, int *idx)
-{
-  pic_value v;
-  int d = 0;
-
- enter:
-
-  v = pic_assq(pic, sym, env->assoc);
-  if (! pic_nil_p(v)) {
-    if (env->parent == NULL) {		/* global */
-      *depth = -1;
-    }
-    else {			/* non-global */
-      *depth = d;
-    }
-    *idx = (int)pic_float(pic_pair_ptr(v)->cdr);
-    return true;
-  }
-  if (env->parent) {
-    env = env->parent;
-    ++d;
-    goto enter;
-  }
-  return false;
-}
-
-static int
-env_global_define(pic_state *pic, pic_value sym)
-{
-  pic_value f;
-  int d, idx;
-
-  if (env_lookup(pic, sym, pic->global_env, &d, &idx)) {
-    return idx;
-  }
-
-  idx = pic->glen++;
-  f = pic_float_value(idx);
-  pic->global_env->assoc = pic_acons(pic, sym, f, pic->global_env->assoc);
-
-  return idx;
-}
-
-static struct pic_env *
-env_new(pic_state *pic, pic_value args, struct pic_env *env)
-{
-  struct pic_env *inner_env;
-  pic_value v, f;
-  int i;
-
-  inner_env = (struct pic_env *)pic_alloc(pic, sizeof(struct pic_env));
-  inner_env->assoc = pic_nil_value();
-  inner_env->parent = env;
-
-  i = -1;
-  for (v = args; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
-    pic_value sym = pic_car(pic, v);
-
-    f = pic_float_value(i--);
-    inner_env->assoc = pic_acons(pic, sym, f, inner_env->assoc);
-  }
-
-  return inner_env;
-}
-
-void
-pic_defun(pic_state *pic, const char *name, pic_func_t cfunc)
-{
-  struct pic_proc *proc;
-  int idx;
-
-  proc = (struct pic_proc *)pic_obj_alloc(pic, sizeof(struct pic_proc), PIC_TT_PROC);
-  proc->cfunc_p = true;
-  proc->u.cfunc = cfunc;
-  idx = env_global_define(pic, pic_intern_cstr(pic, name));
-  pic->globals[idx] = pic_obj_value(proc);
-}
+#include "picrin/proc.h"
+#include "picrin/irep.h"
 
 void
 pic_get_args(pic_state *pic, const char *format, ...)
@@ -118,371 +39,6 @@ pic_get_args(pic_state *pic, const char *format, ...)
   }
 }
 
-static void
-print_irep(pic_state *pic, struct pic_irep *irep)
-{
-  int i;
-
-  printf("## irep %p [clen = %zd, ccapa = %zd]\n", irep, irep->clen, irep->ccapa);
-  for (i = 0; i < irep->clen; ++i) {
-    switch (irep->code[i].insn) {
-    case OP_POP:
-      puts("OP_POP");
-      break;
-    case OP_PUSHNIL:
-      puts("OP_PUSHNIL");
-      break;
-    case OP_PUSHTRUE:
-      puts("OP_PUSHTRUE");
-      break;
-    case OP_PUSHFALSE:
-      puts("OP_PUSHFALSE");
-      break;
-    case OP_PUSHNUM:
-      printf("OP_PUSHNUM\t%g\n", irep->code[i].u.f);
-      break;
-    case OP_GREF:
-      printf("OP_GREF\t%i\n", irep->code[i].u.i);
-      break;
-    case OP_GSET:
-      printf("OP_GSET\t%i\n", irep->code[i].u.i);
-      break;
-    case OP_LREF:
-      printf("OP_LREF\t%d\n", irep->code[i].u.i);
-      break;
-    case OP_JMP:
-      printf("OP_JMP\t%d\n", irep->code[i].u.i);
-      break;
-    case OP_JMPIF:
-      printf("OP_JMPIF\t%d\n", irep->code[i].u.i);
-      break;
-    case OP_CALL:
-      printf("OP_CALL\t%d\n", irep->code[i].u.i);
-      break;
-    case OP_RET:
-      puts("OP_RET");
-      break;
-    case OP_LAMBDA:
-      printf("OP_LAMBDA\t%d\n", irep->code[i].u.i);
-      break;
-    case OP_CONS:
-      puts("OP_CONS");
-      break;
-    case OP_CAR:
-      puts("OP_CAR");
-      break;
-    case OP_NILP:
-      puts("OP_NILP");
-      break;
-    case OP_CDR:
-      puts("OP_CDR");
-      break;
-    case OP_ADD:
-      puts("OP_ADD");
-      break;
-    case OP_SUB:
-      puts("OP_SUB");
-      break;
-    case OP_MUL:
-      puts("OP_MUL");
-      break;
-    case OP_DIV:
-      puts("OP_DIV");
-      break;
-    case OP_STOP:
-      puts("OP_STOP");
-      break;
-    }
-  }
-}
-
-static struct pic_irep *
-new_irep(pic_state *pic)
-{
-  struct pic_irep *irep;
-
-  irep = (struct pic_irep *)pic_alloc(pic, sizeof(struct pic_irep));
-  irep->code = (struct pic_code *)pic_alloc(pic, sizeof(struct pic_code) * 1024);
-  irep->clen = 0;
-  irep->ccapa = 1024;
-  return irep;
-}
-
-static void pic_gen_call(pic_state *, struct pic_irep *, pic_value, struct pic_env *);
-static struct pic_irep *pic_gen_lambda(pic_state *, pic_value, struct pic_env *);
-
-static void
-pic_gen(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *env)
-{
-  pic_value sDEFINE, sLAMBDA, sIF, sBEGIN;
-  pic_value sCONS, sCAR, sCDR, sNILP;
-  pic_value sADD, sSUB, sMUL, sDIV;
-
-  sDEFINE = pic->sDEFINE;
-  sLAMBDA = pic->sLAMBDA;
-  sIF = pic->sIF;
-  sBEGIN = pic->sBEGIN;
-  sCONS = pic->sCONS;
-  sCAR = pic->sCAR;
-  sCDR = pic->sCDR;
-  sNILP = pic->sNILP;
-  sADD = pic->sADD;
-  sSUB = pic->sSUB;
-  sMUL = pic->sMUL;
-  sDIV = pic->sDIV;
-
-  switch (pic_type(obj)) {
-  case PIC_TT_SYMBOL: {
-    bool b;
-    int depth, idx;
-
-    b = env_lookup(pic, obj, env, &depth, &idx);
-    if (! b) {
-      pic_raise(pic, "unbound variable");
-    }
-
-    if (depth == -1) {		/* global */
-      irep->code[irep->clen].insn = OP_GREF;
-      irep->code[irep->clen].u.i = idx;
-      irep->clen++;
-    }
-    else if (depth == 0) {	/* local */
-      irep->code[irep->clen].insn = OP_LREF;
-      irep->code[irep->clen].u.i = idx;
-      irep->clen++;
-    }
-    else {			/* nonlocal */
-      pic_raise(pic, "reference to closed variable not supported");
-    }
-    break;
-  }
-  case PIC_TT_PAIR: {
-    pic_value proc;
-
-    proc = pic_car(pic, obj);
-    if (pic_eq_p(pic, proc, sDEFINE)) {
-      int idx;
-
-      idx = env_global_define(pic, pic_car(pic, pic_cdr(pic, obj)));
-
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-
-      irep->code[irep->clen].insn = OP_GSET;
-      irep->code[irep->clen].u.i = idx;
-      irep->clen++;
-      irep->code[irep->clen].insn = OP_PUSHFALSE;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sLAMBDA)) {
-      irep->code[irep->clen].insn = OP_LAMBDA;
-      irep->code[irep->clen].u.i = pic->ilen;
-      irep->clen++;
-
-      pic->irep[pic->ilen++] = pic_gen_lambda(pic, obj, env);
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sIF)) {
-      int s,t;
-
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-
-      irep->code[irep->clen].insn = OP_JMPIF;
-      s = irep->clen++;
-
-      /* if false branch */
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, pic_cdr(pic, obj)))), env);
-      irep->code[irep->clen].insn = OP_JMP;
-      t = irep->clen++;
-
-      irep->code[s].u.i = irep->clen - s;
-
-      /* if true branch */
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      irep->code[t].u.i = irep->clen - t;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sBEGIN)) {
-      pic_value v, seq;
-
-      seq = pic_cdr(pic, obj);
-      for (v = seq; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
-	pic_gen(pic, irep, pic_car(pic, v), env);
-	irep->code[irep->clen].insn = OP_POP;
-	irep->clen++;
-      }
-      irep->clen--;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sCONS)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_CONS;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sCAR)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_CAR;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sCDR)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_CDR;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sNILP)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_NILP;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sADD)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_ADD;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sSUB)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_SUB;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sMUL)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_MUL;
-      irep->clen++;
-      break;
-    }
-    else if (pic_eq_p(pic, proc, sDIV)) {
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, pic_cdr(pic, obj))), env);
-      pic_gen(pic, irep, pic_car(pic, pic_cdr(pic, obj)), env);
-      irep->code[irep->clen].insn = OP_DIV;
-      irep->clen++;
-      break;
-    }
-    else {
-      pic_gen_call(pic, irep, obj, env);
-      break;
-    }
-  }
-  case PIC_TT_BOOL: {
-    if (pic_true_p(obj)) {
-      irep->code[irep->clen].insn = OP_PUSHTRUE;
-    }
-    else {
-      irep->code[irep->clen].insn = OP_PUSHFALSE;
-    }
-    irep->clen++;
-    break;
-  }
-  case PIC_TT_FLOAT: {
-    irep->code[irep->clen].insn = OP_PUSHNUM;
-    irep->code[irep->clen].u.f = pic_float(obj);
-    irep->clen++;
-    break;
-  }
-  case PIC_TT_NIL: {
-    irep->code[irep->clen].insn = OP_PUSHNIL;
-    irep->clen++;
-    break;
-  }
-  case PIC_TT_PROC:
-  case PIC_TT_UNDEF:
-  case PIC_TT_PORT: {
-    pic_raise(pic, "invalid expression given");
-  }
-  }
-}
-
-static pic_value
-reverse(pic_state *pic, pic_value list, pic_value acc)
-{
-  if (pic_nil_p(list))
-    return acc;
-  return reverse(pic, pic_cdr(pic, list), pic_cons(pic, pic_car(pic, list), acc));
-}
-
-static void
-pic_gen_call(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *env)
-{
-  pic_value seq;
-  int i = 0;
-
-  seq = reverse(pic, obj, pic_nil_value());
-  for (; ! pic_nil_p(seq); seq = pic_cdr(pic, seq)) {
-    pic_value v;
-
-    v = pic_car(pic, seq);
-    pic_gen(pic, irep, v, env);
-    ++i;
-  }
-  irep->code[irep->clen].insn = OP_CALL;
-  irep->code[irep->clen].u.i = i;
-  irep->clen++;
-}
-
-static struct pic_irep *
-pic_gen_lambda(pic_state *pic, pic_value obj, struct pic_env *env)
-{
-  struct pic_env *inner_env;
-  pic_value args, body, v;
-  struct pic_irep *irep;
-
-  irep = new_irep(pic);
-
-  /* arguments */
-  args = pic_car(pic, pic_cdr(pic, obj));
-  inner_env = env_new(pic, args, env);
-
-  /* body */
-  body = pic_cdr(pic, pic_cdr(pic, obj));
-  for (v = body; ! pic_nil_p(v); v = pic_cdr(pic, v)) {
-    pic_gen(pic, irep, pic_car(pic, v), inner_env);
-    irep->code[irep->clen].insn = OP_POP;
-    irep->clen++;
-  }
-  irep->clen--;
-  irep->code[irep->clen].insn = OP_RET;
-  irep->clen++;
-  pic_free(pic, inner_env);
-
-#if VM_DEBUG
-  printf("LAMBDA_%zd:\n", pic->ilen);
-  print_irep(pic, irep);
-  puts("");
-#endif
-
-  return irep;
-}
-
-struct pic_proc *
-pic_codegen(pic_state *pic, pic_value obj, struct pic_env *env)
-{
-  struct pic_proc *proc;
-  struct pic_irep *irep;
-
-  proc = (struct pic_proc *)pic_obj_alloc(pic, sizeof(struct pic_proc), PIC_TT_PROC);
-  proc->cfunc_p = false;
-  proc->u.irep = irep = new_irep(pic);
-
-  pic_gen(pic, irep, obj, env);
-  irep->code[irep->clen].insn = OP_STOP;
-  irep->clen++;
-
-#if VM_DEBUG
-  print_irep(pic, irep);
-#endif
-
-  return proc;
-}
-
 #if PIC_DIRECT_THREADED_VM
 # define VM_LOOP JUMP;
 # define CASE(x) L_##x: