Added other methods for Binding

- Added to `mruby-binding-core`
  - `Binding#local_variable_defined?`
  - `Binding#local_variable_get`
  - `Binding#local_variable_set`
  - `Binding#local_variables`
  - `Binding#receiver`
  - `Binding#source_location`
  - `Binding#inspect`
- Added to `mruby-proc-binding`
  - `Proc#binding`

The reason for separating `Proc#binding` is that core-mrbgems has a method that returns a closure object to minimize possible problems with being able to manipulate internal variables.
By separating it as different mrbgem, each user can judge this problem and incorporate it arbitrarily.

mrbgems/mruby-binding-core/mrbgem.rake

@@ -1,5 +1,7 @@
 MRuby::Gem::Specification.new('mruby-binding-core') do |spec|
   spec.license = 'MIT'
   spec.author  = 'mruby developers'
-  spec.summary = 'Binding class'
+  spec.summary = 'Binding class (core features only)'
+
+  spec.add_test_dependency('mruby-proc-ext', :core => 'mruby-proc-ext')
 end

mrbgems/mruby-binding-core/src/binding-core.c

@@ -4,8 +4,160 @@
 #include <mruby/proc.h>
 #include <mruby/variable.h>
 #include <mruby/presym.h>
+#include <mruby/opcode.h>
+#include <mruby/debug.h>
 
+void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
 mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
+const struct RProc *mrb_proc_get_caller(mrb_state *mrb, struct REnv **env);
+
+static mrb_int
+binding_extract_pc(mrb_state *mrb, mrb_value binding)
+{
+  mrb_value obj = mrb_iv_get(mrb, binding, MRB_SYM(pc));
+  if (mrb_nil_p(obj)) {
+    return -1;
+  }
+  else {
+    mrb_check_type(mrb, obj, MRB_TT_INTEGER);
+    return mrb_int(mrb, obj);
+  }
+}
+
+static const struct RProc *
+binding_extract_proc(mrb_state *mrb, mrb_value binding)
+{
+  mrb_value obj = mrb_iv_get(mrb, binding, MRB_SYM(proc));
+  mrb_check_type(mrb, obj, MRB_TT_PROC);
+  return mrb_proc_ptr(obj);
+}
+
+static struct REnv *
+binding_extract_env(mrb_state *mrb, mrb_value binding)
+{
+  mrb_value obj = mrb_iv_get(mrb, binding, MRB_SYM(env));
+  if (mrb_nil_p(obj)) {
+    return NULL;
+  }
+  else {
+    mrb_check_type(mrb, obj, MRB_TT_ENV);
+    return (struct REnv *)mrb_obj_ptr(obj);
+  }
+}
+
+static void
+binding_local_variable_name_check(mrb_state *mrb, mrb_sym id)
+{
+  if (id == 0) {
+  badname:
+    mrb_raisef(mrb, E_NAME_ERROR, "wrong local variable name %!n for binding", id);
+  }
+
+  mrb_int len;
+  const char *name = mrb_sym_name_len(mrb, id, &len);
+  if (len == 0) {
+    goto badname;
+  }
+
+  if (ISASCII(*name) && !(*name == '_' || ISLOWER(*name))) {
+    goto badname;
+  }
+  len--;
+  name++;
+
+  for (; len > 0; len--, name++) {
+    if (ISASCII(*name) && !(*name == '_' || ISALNUM(*name))) {
+      goto badname;
+    }
+  }
+}
+
+static mrb_value *
+binding_local_variable_search(mrb_state *mrb, const struct RProc *proc, struct REnv *env, mrb_sym varname)
+{
+  binding_local_variable_name_check(mrb, varname);
+
+  while (proc) {
+    if (MRB_PROC_CFUNC_P(proc)) break;
+
+    const mrb_irep *irep = proc->body.irep;
+    const mrb_sym *lv;
+    if (irep && (lv = irep->lv)) {
+      for (int i = 0; i + 1 < irep->nlocals; i++, lv++) {
+        if (varname == *lv) {
+          return (env && MRB_ENV_LEN(env) > i) ? &env->stack[i + 1] : NULL;
+        }
+      }
+    }
+
+    if (MRB_PROC_SCOPE_P(proc)) break;
+    env = MRB_PROC_ENV(proc);
+    proc = proc->upper;
+  }
+
+  return NULL;
+}
+
+/*
+ * call-seq:
+ *  local_variable_defined?(symbol) -> bool
+ */
+static mrb_value
+binding_local_variable_defined_p(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym varname;
+  mrb_get_args(mrb, "n", &varname);
+
+  const struct RProc *proc = binding_extract_proc(mrb, self);
+  struct REnv *env = binding_extract_env(mrb, self);
+  mrb_value *e = binding_local_variable_search(mrb, proc, env, varname);
+  if (e) {
+    return mrb_true_value();
+  }
+  else {
+    return mrb_false_value();
+  }
+}
+
+/*
+ * call-seq:
+ *  local_variable_get(symbol) -> object
+ */
+static mrb_value
+binding_local_variable_get(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym varname;
+  mrb_get_args(mrb, "n", &varname);
+
+  const struct RProc *proc = binding_extract_proc(mrb, self);
+  struct REnv *env = binding_extract_env(mrb, self);
+  mrb_value *e = binding_local_variable_search(mrb, proc, env, varname);
+  if (!e) {
+    mrb_raisef(mrb, E_NAME_ERROR, "local variable %!n is not defined", varname);
+  }
+
+  return *e;
+}
+
+static mrb_value
+binding_local_variable_set(mrb_state *mrb, mrb_value self)
+{
+  mrb_sym varname;
+  mrb_value obj;
+  mrb_get_args(mrb, "no", &varname, &obj);
+
+  const struct RProc *proc = binding_extract_proc(mrb, self);
+  struct REnv *env = binding_extract_env(mrb, self);
+  mrb_value *e = binding_local_variable_search(mrb, proc, env, varname);
+  if (e) {
+    *e = obj;
+  }
+  else {
+    mrb_proc_merge_lvar(mrb, (mrb_irep*)proc->body.irep, env, 1, &varname, &obj);
+  }
+
+  return obj;
+}
 
 static mrb_value
 binding_local_variables(mrb_state *mrb, mrb_value self)
@@ -14,19 +166,119 @@ binding_local_variables(mrb_state *mrb, mrb_value self)
   return mrb_proc_local_variables(mrb, proc);
 }
 
-const struct RProc *mrb_proc_get_caller(mrb_state *mrb, struct REnv **env);
+static mrb_value
+binding_receiver(mrb_state *mrb, mrb_value self)
+{
+  return mrb_iv_get(mrb, self, MRB_SYM(recv));
+}
+
+/*
+ * call-seq:
+ *  source_location -> [String, Integer]
+ */
+static mrb_value
+binding_source_location(mrb_state *mrb, mrb_value self)
+{
+  if (mrb_iv_defined(mrb, self, MRB_SYM(source_location))) {
+    return mrb_iv_get(mrb, self, MRB_SYM(source_location));
+  }
+
+  mrb_value srcloc;
+  const struct RProc *proc = binding_extract_proc(mrb, self);
+  if (!proc || MRB_PROC_CFUNC_P(proc) ||
+      !proc->upper || MRB_PROC_CFUNC_P(proc->upper)) {
+    srcloc = mrb_nil_value();
+    goto cache_source_location;
+  }
+
+  {
+    const mrb_irep *irep = proc->upper->body.irep;
+    mrb_int pc = binding_extract_pc(mrb, self);
+    if (pc < 0) {
+      srcloc = mrb_nil_value();
+    }
+    else {
+      const char *fname = mrb_debug_get_filename(mrb, irep, pc);
+      mrb_int fline = mrb_debug_get_line(mrb, irep, pc);
+
+      if (fname && fline >= 0) {
+        srcloc = mrb_assoc_new(mrb, mrb_str_new_cstr(mrb, fname), mrb_fixnum_value(fline));
+      }
+      else {
+        srcloc = mrb_nil_value();
+      }
+    }
+  }
+
+cache_source_location:
+  if (!mrb_frozen_p(mrb_obj_ptr(self))) {
+    mrb_iv_set(mrb, self, MRB_SYM(source_location), srcloc);
+  }
+  return srcloc;
+}
+
+mrb_value
+mrb_binding_alloc(mrb_state *mrb)
+{
+  struct RObject *obj = (struct RObject*)mrb_obj_alloc(mrb, MRB_TT_OBJECT, mrb_class_get(mrb, "Binding"));
+  return mrb_obj_value(obj);
+}
+
+struct RProc*
+mrb_binding_wrap_lvspace(mrb_state *mrb, const struct RProc *proc, struct REnv **envp)
+{
+  /*
+   * local variable space: It is a space to hold the top-level variable of
+   * binding.eval and binding.local_variable_set.
+   */
+
+  static const mrb_code iseq_dummy[] = { OP_RETURN, 0 };
+
+  struct RProc *lvspace = (struct RProc*)mrb_obj_alloc(mrb, MRB_TT_PROC, mrb->proc_class);
+  mrb_irep *irep = mrb_add_irep(mrb);
+  irep->flags = MRB_ISEQ_NO_FREE;
+  irep->iseq = iseq_dummy;
+  irep->ilen = sizeof(iseq_dummy) / sizeof(iseq_dummy[0]);
+  irep->lv = (mrb_sym*)mrb_calloc(mrb, 1, sizeof(mrb_sym)); /* initial allocation for dummy */
+  irep->nlocals = 1;
+  irep->nregs = 1;
+  lvspace->body.irep = irep;
+  lvspace->upper = proc;
+  if (*envp) {
+    lvspace->e.env = *envp;
+    lvspace->flags |= MRB_PROC_ENVSET;
+  }
+
+  *envp = (struct REnv*)mrb_obj_alloc(mrb, MRB_TT_ENV, NULL);
+  (*envp)->stack = (mrb_value*)mrb_calloc(mrb, 1, sizeof(mrb_value));
+  (*envp)->stack[0] = lvspace->e.env ? lvspace->e.env->stack[0] : mrb_nil_value();
+  (*envp)->cxt = lvspace->e.env ? lvspace->e.env->cxt : mrb->c;
+  (*envp)->mid = 0;
+  (*envp)->flags = MRB_ENV_CLOSED | MRB_ENV_HEAPED;
+  MRB_ENV_SET_LEN(*envp, 1);
+
+  return lvspace;
+}
 
 static mrb_value
 mrb_f_binding(mrb_state *mrb, mrb_value self)
 {
-  struct RObject *obj;
   mrb_value binding;
   struct RProc *proc;
   struct REnv *env;
 
-  obj = (struct RObject*)mrb_obj_alloc(mrb, MRB_TT_OBJECT, mrb_class_get(mrb, "Binding"));
-  binding = mrb_obj_value(obj);
+  binding = mrb_binding_alloc(mrb);
   proc = (struct RProc*)mrb_proc_get_caller(mrb, &env);
+  if (!env || MRB_PROC_CFUNC_P(proc)) {
+    proc = NULL;
+    env = NULL;
+  }
+
+  if (proc && !MRB_PROC_CFUNC_P(proc)) {
+    const mrb_irep *irep = proc->body.irep;
+    mrb_iv_set(mrb, binding, MRB_SYM(pc), mrb_fixnum_value(mrb->c->ci[-1].pc - irep->iseq - 1 /* step back */));
+  }
+  proc = mrb_binding_wrap_lvspace(mrb, proc, &env);
   mrb_iv_set(mrb, binding, MRB_SYM(proc), mrb_obj_value(proc));
   mrb_iv_set(mrb, binding, MRB_SYM(recv), self);
   mrb_iv_set(mrb, binding, MRB_SYM(env), mrb_obj_value(env));
@@ -42,7 +294,13 @@ mrb_mruby_binding_core_gem_init(mrb_state *mrb)
 
   mrb_define_method(mrb, mrb->kernel_module, "binding", mrb_f_binding, MRB_ARGS_NONE());
 
+  mrb_define_method(mrb, binding, "local_variable_defined?", binding_local_variable_defined_p, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, binding, "local_variable_get", binding_local_variable_get, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, binding, "local_variable_set", binding_local_variable_set, MRB_ARGS_REQ(2));
   mrb_define_method(mrb, binding, "local_variables", binding_local_variables, MRB_ARGS_NONE());
+  mrb_define_method(mrb, binding, "receiver", binding_receiver, MRB_ARGS_NONE());
+  mrb_define_method(mrb, binding, "source_location", binding_source_location, MRB_ARGS_NONE());
+  mrb_define_method(mrb, binding, "inspect", mrb_any_to_s, MRB_ARGS_NONE());
 }
 
 void

mrbgems/mruby-binding-core/test/binding-core.rb

@@ -9,3 +9,32 @@ assert("Binding#local_variables") do
   end
   assert_equal [:a, :b, :block], block.call(0).local_variables.sort
 end
+
+assert("Binding#local_variable_set") do
+  bind = binding
+  1.times {
+    assert_equal(9, bind.local_variable_set(:x, 9))
+    assert_raise(NameError) { x }
+    assert_equal([:bind, :x], bind.local_variables.sort)
+  }
+end
+
+assert("Binding#local_variable_get") do
+  bind = binding
+  x = 1
+  1.times {
+    y = 2
+    assert_equal(1, bind.local_variable_get(:x))
+    x = 10
+    assert_equal(10, bind.local_variable_get(:x))
+    assert_raise(NameError) { bind.local_variable_get(:y) }
+    assert_equal([:bind, :x], bind.local_variables.sort)
+  }
+end
+
+assert("Binding#source_location") do
+  skip unless -> {}.source_location
+
+  bind, source_location = binding, [__FILE__, __LINE__]
+  assert_equal source_location, bind.source_location
+end

mrbgems/mruby-binding/mrbgem.rake

@@ -5,4 +5,7 @@ MRuby::Gem::Specification.new('mruby-binding') do |spec|
 
   spec.add_dependency('mruby-binding-core', :core => 'mruby-binding-core')
   spec.add_dependency('mruby-eval', :core => 'mruby-eval')
+  spec.add_test_dependency('mruby-metaprog', :core => 'mruby-metaprog')
+  spec.add_test_dependency('mruby-method', :core => 'mruby-method')
+  spec.add_test_dependency('mruby-proc-ext', :core => 'mruby-proc-ext')
 end

mrbgems/mruby-binding/test/binding.c

@@ -0,0 +1,13 @@
+#include <mruby.h>
+
+static mrb_value
+binding_in_c(mrb_state *mrb, mrb_value self)
+{
+  return mrb_funcall_argv(mrb, mrb_obj_value(mrb->object_class), mrb_intern_lit(mrb, "binding"), 0, NULL);
+}
+
+void
+mrb_mruby_binding_gem_test(mrb_state *mrb)
+{
+  mrb_define_method(mrb, mrb->object_class, "binding_in_c", binding_in_c, MRB_ARGS_NONE());
+}

mrbgems/mruby-binding/test/binding.rb

@@ -2,4 +2,69 @@ assert("Binding#eval") do
   b = nil
   1.times { x, y, z = 1, 2, 3; [x,y,z]; b = binding }
   assert_equal([1, 2, 3], b.eval("[x, y, z]"))
+  here = self
+  assert_equal(here, b.eval("self"))
+end
+
+assert("Binding#local_variables") do
+  block = Proc.new do |a|
+    b = 1
+    binding
+  end
+  bind = block.call(0)
+  assert_equal [:a, :b, :bind, :block], bind.local_variables.sort
+  bind.eval("x = 2")
+  assert_equal [:a, :b, :bind, :block, :x], bind.local_variables.sort
+end
+
+assert("Binding#local_variable_set") do
+  bind = binding
+  1.times {
+    assert_equal(9, bind.local_variable_set(:x, 9))
+    assert_equal(9, bind.eval("x"))
+    assert_equal([:bind, :x], bind.eval("local_variables.sort"))
+  }
+end
+
+assert("Binding#local_variable_get") do
+  bind = binding
+  x = 1
+  1.times {
+    y = 2
+    assert_equal(1, bind.local_variable_get(:x))
+    x = 10
+    assert_equal(10, bind.local_variable_get(:x))
+    assert_raise(NameError) { bind.local_variable_get(:y) }
+    bind.eval("z = 3")
+    assert_equal(3, bind.local_variable_get(:z))
+    bind.eval("y = 5")
+    assert_equal(5, bind.local_variable_get(:y))
+    assert_equal(2, y)
+  }
+end
+
+assert("Binding#source_location") do
+  skip unless -> {}.source_location
+
+  bind, source_location = binding, [__FILE__, __LINE__]
+  assert_equal source_location, bind.source_location
+end
+
+assert "Kernel#binding and .eval from C" do
+  bind = binding_in_c
+  assert_equal 5, bind.eval("2 + 3")
+  assert_nothing_raised { bind.eval("self") }
+end
+
+assert "Binding#eval with Binding.new via UnboundMethod" do
+  assert_raise(NoMethodError) { Class.instance_method(:new).bind_call(Binding) }
+end
+
+assert "Binding#eval with Binding.new via Method" do
+  # The following test is OK if SIGSEGV does not occur
+  cx = Class.new(Binding)
+  cx.define_singleton_method(:allocate, &Object.method(:allocate))
+  Class.instance_method(:new).bind_call(cx).eval("")
+
+  assert_true true
 end

mrbgems/mruby-eval/src/eval.c

@@ -9,10 +9,10 @@
 #include <mruby/variable.h>
 
 struct REnv *mrb_env_new(mrb_state *mrb, struct mrb_context *c, mrb_callinfo *ci, int nstacks, mrb_value *stack, struct RClass *tc);
-mrb_value mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p);
+mrb_value mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p, mrb_func_t posthook);
 mrb_value mrb_obj_instance_eval(mrb_state *mrb, mrb_value self);
-
 void mrb_codedump_all(mrb_state*, struct RProc*);
+void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
 
 static struct RProc*
 create_proc_from_string(mrb_state *mrb, const char *s, mrb_int len, mrb_value binding, const char *file, mrb_int line)
@@ -127,7 +127,7 @@ create_proc_from_string(mrb_state *mrb, const char *s, mrb_int len, mrb_value bi
 }
 
 static mrb_value
-exec_irep(mrb_state *mrb, mrb_value self, struct RProc *proc)
+exec_irep(mrb_state *mrb, mrb_value self, struct RProc *proc, mrb_func_t posthook)
 {
   /* no argument passed from eval() */
   mrb->c->ci->argc = 0;
@@ -142,7 +142,38 @@ exec_irep(mrb_state *mrb, mrb_value self, struct RProc *proc)
   }
   /* clear block */
   mrb->c->ci->stack[1] = mrb_nil_value();
-  return mrb_exec_irep(mrb, self, proc);
+  return mrb_exec_irep(mrb, self, proc, posthook);
+}
+
+static void
+eval_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack)
+{
+  mrb_assert(mrb->c->stend >= stack + num);
+  mrb_proc_merge_lvar(mrb, irep, env, num, lv, stack);
+}
+
+static mrb_value
+eval_merge_lvar_hook(mrb_state *mrb, mrb_value dummy_self)
+{
+  const mrb_callinfo *orig_ci = &mrb->c->ci[1];
+  const struct RProc *orig_proc = orig_ci->proc;
+  const mrb_irep *orig_irep = orig_proc->body.irep;
+  int orig_nlocals = orig_irep->nlocals;
+
+  if (orig_nlocals > 1) {
+    struct RProc *proc = (struct RProc *)orig_proc->upper;
+    struct REnv *env = MRB_PROC_ENV(orig_proc);
+    eval_merge_lvar(mrb, (mrb_irep *)proc->body.irep, env,
+                    orig_nlocals - 1, orig_irep->lv,
+                    mrb->c->ci->stack + 3 /* hook proc + exc + ret val */);
+  }
+
+  mrb_value exc = mrb->c->ci->stack[1];
+  if (!mrb_nil_p(exc)) {
+    mrb_exc_raise(mrb, exc);
+  }
+
+  return mrb->c->ci->stack[2];
 }
 
 static mrb_value
@@ -154,15 +185,19 @@ f_eval(mrb_state *mrb, mrb_value self)
   const char *file = NULL;
   mrb_int line = 1;
   struct RProc *proc;
+  mrb_func_t posthook = NULL;
 
   mrb_get_args(mrb, "s|ozi", &s, &len, &binding, &file, &line);
 
   proc = create_proc_from_string(mrb, s, len, binding, file, line);
   if (!mrb_nil_p(binding)) {
     self = mrb_iv_get(mrb, binding, MRB_SYM(recv));
+    if (mrb_env_p(mrb_iv_get(mrb, binding, MRB_SYM(env)))) {
+      posthook = eval_merge_lvar_hook;
+    }
   }
   mrb_assert(!MRB_PROC_CFUNC_P(proc));
-  return exec_irep(mrb, self, proc);
+  return exec_irep(mrb, self, proc, posthook);
 }
 
 static mrb_value
@@ -187,7 +222,7 @@ f_instance_eval(mrb_state *mrb, mrb_value self)
     MRB_PROC_SET_TARGET_CLASS(proc, mrb_class_ptr(cv));
     mrb_assert(!MRB_PROC_CFUNC_P(proc));
     mrb_vm_ci_target_class_set(mrb->c->ci, mrb_class_ptr(cv));
-    return exec_irep(mrb, self, proc);
+    return exec_irep(mrb, self, proc, NULL);
   }
   else {
     mrb_get_args(mrb, "&", &b);

mrbgems/mruby-metaprog/src/metaprog.c

@@ -21,6 +21,8 @@ typedef enum {
   NOEX_RESPONDS  = 0x80
 } mrb_method_flag_t;
 
+mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
+
 static mrb_value
 mrb_f_nil(mrb_state *mrb, mrb_value cv)
 {
@@ -117,8 +119,6 @@ mrb_obj_ivar_set(mrb_state *mrb, mrb_value self)
   return val;
 }
 
-mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
-
 /* 15.3.1.2.7 */
 /* 15.3.1.3.28 */
 /*

mrbgems/mruby-proc-binding/mrbgem.rake

@@ -0,0 +1,9 @@
+MRuby::Gem::Specification.new('mruby-proc-binding') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'Proc#binding method'
+
+  spec.add_dependency('mruby-binding-core', :core => 'mruby-binding-core')
+  spec.add_test_dependency('mruby-binding', :core => 'mruby-binding')
+  spec.add_test_dependency('mruby-compiler', :core => 'mruby-compiler')
+end

mrbgems/mruby-proc-binding/src/proc-binding.c

@@ -0,0 +1,52 @@
+#include <mruby.h>
+#include <mruby/presym.h>
+#include <mruby/proc.h>
+#include <mruby/variable.h>
+
+void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
+
+/* provided by mruby-proc-ext */
+mrb_value mrb_proc_source_location(mrb_state *mrb, struct RProc *p);
+
+/* provided by mruby-binding-core */
+mrb_value mrb_binding_alloc(mrb_state *mrb);
+struct RProc *mrb_binding_wrap_lvspace(mrb_state *mrb, const struct RProc *proc, struct REnv **envp);
+
+static mrb_value
+mrb_proc_binding(mrb_state *mrb, mrb_value procval)
+{
+  mrb_value binding = mrb_binding_alloc(mrb);
+  const struct RProc *proc = mrb_proc_ptr(procval);
+  struct REnv *env;
+
+  mrb_value receiver;
+  if (!proc || MRB_PROC_CFUNC_P(proc) || !proc->upper || MRB_PROC_CFUNC_P(proc->upper)) {
+    env = NULL;
+    proc = NULL;
+    receiver = mrb_nil_value();
+  }
+  else {
+    env = MRB_PROC_ENV(proc);
+    mrb_assert(env);
+    proc = proc->upper;
+    receiver = MRB_ENV_LEN(env) > 0 ? env->stack[0] : mrb_nil_value();
+  }
+
+  proc = mrb_binding_wrap_lvspace(mrb, proc, &env);
+  mrb_iv_set(mrb, binding, MRB_SYM(proc), mrb_obj_value((void *)proc));
+  mrb_iv_set(mrb, binding, MRB_SYM(recv), receiver);
+  mrb_iv_set(mrb, binding, MRB_SYM(env), mrb_obj_value(env));
+  mrb_iv_set(mrb, binding, MRB_SYM(source_location), mrb_proc_source_location(mrb, mrb_proc_ptr(procval)));
+  return binding;
+}
+
+void
+mrb_mruby_proc_binding_gem_init(mrb_state *mrb)
+{
+  mrb_define_method(mrb, mrb->proc_class, "binding", mrb_proc_binding, MRB_ARGS_NONE());
+}
+
+void
+mrb_mruby_proc_binding_gem_final(mrb_state *mrb)
+{
+}

mrbgems/mruby-proc-binding/test/proc-binding.c

@@ -0,0 +1,14 @@
+#include <mruby.h>
+#include <mruby/compile.h>
+
+static mrb_value
+proc_in_c(mrb_state *mrb, mrb_value self)
+{
+  return mrb_load_string(mrb, "proc { |a, b| a + b }");
+}
+
+void
+mrb_mruby_proc_binding_gem_test(mrb_state *mrb)
+{
+  mrb_define_method(mrb, mrb->object_class, "proc_in_c", proc_in_c, MRB_ARGS_NONE());
+}

mrbgems/mruby-proc-binding/test/proc-binding.rb

@@ -0,0 +1,22 @@
+assert "Proc#binding" do
+  block = ->(i) {}
+  a, b, c = 1, 2, 3
+  bind = block.binding
+  assert_equal([:a, :b, :bind, :block, :c], bind.local_variables.sort)
+  assert_equal(1, bind.local_variable_get(:a))
+  assert_equal(5, bind.eval("b + c"))
+  bind.local_variable_set(:x, 9)
+  assert_equal(9, bind.local_variable_get(:x))
+end
+
+assert("Binding#source_location after Proc#binding") do
+  skip unless -> {}.source_location
+
+  block, source_location = -> {}, [__FILE__, __LINE__]
+  assert_equal source_location, block.binding.source_location
+end
+
+assert "Proc#binding and .eval from C" do
+  bind = proc_in_c.binding
+  assert_nothing_raised { bind.eval("self") }
+end

mrbgems/mruby-proc-ext/src/proc.c

@@ -13,11 +13,9 @@ mrb_proc_lambda_p(mrb_state *mrb, mrb_value self)
   return mrb_bool_value(MRB_PROC_STRICT_P(p));
 }
 
-static mrb_value
-mrb_proc_source_location(mrb_state *mrb, mrb_value self)
+mrb_value
+mrb_proc_source_location(mrb_state *mrb, struct RProc *p)
 {
-  struct RProc *p = mrb_proc_ptr(self);
-
   if (MRB_PROC_CFUNC_P(p)) {
     return mrb_nil_value();
   }
@@ -34,6 +32,12 @@ mrb_proc_source_location(mrb_state *mrb, mrb_value self)
   }
 }
 
+static mrb_value
+mrb_proc_source_location_m(mrb_state *mrb, mrb_value self)
+{
+  return mrb_proc_source_location(mrb, mrb_proc_ptr(self));
+}
+
 static mrb_value
 mrb_proc_inspect(mrb_state *mrb, mrb_value self)
 {
@@ -183,7 +187,7 @@ mrb_mruby_proc_ext_gem_init(mrb_state* mrb)
 {
   struct RClass *p = mrb->proc_class;
   mrb_define_method(mrb, p, "lambda?",         mrb_proc_lambda_p,        MRB_ARGS_NONE());
-  mrb_define_method(mrb, p, "source_location", mrb_proc_source_location, MRB_ARGS_NONE());
+  mrb_define_method(mrb, p, "source_location", mrb_proc_source_location_m, MRB_ARGS_NONE());
   mrb_define_method(mrb, p, "to_s",            mrb_proc_inspect,         MRB_ARGS_NONE());
   mrb_define_method(mrb, p, "inspect",         mrb_proc_inspect,         MRB_ARGS_NONE());
   mrb_define_method(mrb, p, "parameters",      mrb_proc_parameters,      MRB_ARGS_NONE());

src/proc.c

@@ -372,6 +372,44 @@ mrb_proc_get_caller(mrb_state *mrb, struct REnv **envp)
   return proc;
 }
 
+#define IREP_LVAR_MERGE_DEFAULT  50
+#define IREP_LVAR_MERGE_MINIMUM   8
+#define IREP_LVAR_MERGE_MAXIMUM 240
+
+#ifdef MRB_IREP_LVAR_MERGE_LIMIT
+# define IREP_LVAR_MERGE_LIMIT \
+  ((MRB_IREP_LVAR_MERGE_LIMIT) < IREP_LVAR_MERGE_MINIMUM ? IREP_LVAR_MERGE_MINIMUM : \
+   (MRB_IREP_LVAR_MERGE_LIMIT) > IREP_LVAR_MERGE_MAXIMUM ? IREP_LVAR_MERGE_MAXIMUM : \
+   (MRB_IREP_LVAR_MERGE_LIMIT))
+#else
+# define IREP_LVAR_MERGE_LIMIT IREP_LVAR_MERGE_DEFAULT
+#endif
+
+void
+mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack)
+{
+  mrb_assert(!(irep->flags & MRB_IREP_NO_FREE));
+
+  if ((irep->nlocals + num) > IREP_LVAR_MERGE_LIMIT) {
+    mrb_raise(mrb, E_RUNTIME_ERROR, "too many local variables for binding (mruby limitation)");
+  }
+
+  if (!lv) {
+    mrb_raise(mrb, E_RUNTIME_ERROR, "unavailable local variable names");
+  }
+
+  irep->lv = (mrb_sym*)mrb_realloc(mrb, (mrb_sym*)irep->lv, sizeof(mrb_sym) * (irep->nlocals + num));
+  env->stack = (mrb_value*)mrb_realloc(mrb, env->stack, sizeof(mrb_value) * (irep->nlocals + 1 /* self */ + num));
+
+  mrb_sym *destlv = (mrb_sym*)irep->lv + irep->nlocals - 1 /* self */;
+  mrb_value *destst = env->stack + irep->nlocals;
+  memmove(destlv, lv, sizeof(mrb_sym) * num);
+  memmove(destst, stack, sizeof(mrb_value) * num);
+  irep->nlocals += num;
+  irep->nregs = irep->nlocals;
+  MRB_ENV_SET_LEN(env, irep->nlocals);
+}
+
 void
 mrb_init_proc(mrb_state *mrb)
 {

src/vm.c

@@ -483,13 +483,73 @@ mrb_funcall_argv(mrb_state *mrb, mrb_value self, mrb_sym mid, mrb_int argc, cons
   return mrb_funcall_with_block(mrb, self, mid, argc, argv, mrb_nil_value());
 }
 
+#define DECOMPOSE32(n) (((n) >> 24) & 0xff), (((n) >> 16) & 0xff), (((n) >> 8) & 0xff), (((n) >> 0) & 0xff)
+#define CATCH_HANDLER_MAKE_BYTECODE(t, b, e, j) t, DECOMPOSE32(b), DECOMPOSE32(e), DECOMPOSE32(j)
+#define CATCH_HANDLER_NUM_TO_BYTE(n) ((n) * sizeof(struct mrb_irep_catch_handler))
+
+static void
+mrb_exec_irep_prepare_posthook(mrb_state *mrb, mrb_callinfo *ci, int nregs, mrb_func_t posthook)
+{
+  /*
+   *  stack: [proc, errinfo, return value by called proc]
+   *
+   *  begin
+   *    OP_NOP        # A dummy instruction built in to make the catch handler react.
+   *  ensure
+   *    OP_EXCEPT R1  # Save the exception object.
+   *    OP_CALL       # Call a C function for the hook.
+   *                  # The stack is kept as it is in the called proc.
+   *                  # The exception will be rethrown within the hook function.
+   *  end
+   */
+  static const mrb_code hook_iseq[] = {
+    OP_NOP,
+    OP_EXCEPT, 1,
+    OP_CALL,
+    CATCH_HANDLER_MAKE_BYTECODE(MRB_CATCH_ENSURE, 0, 1, 1),
+  };
+  static const mrb_irep hook_irep = {
+    1, 3, 1, MRB_IREP_STATIC, hook_iseq,
+    NULL, NULL, NULL, NULL, NULL,
+    sizeof(hook_iseq) / sizeof(hook_iseq[0]) - CATCH_HANDLER_NUM_TO_BYTE(1),
+    0, 0, 0, 0
+  };
+  static const struct RProc hook_caller = {
+    NULL, NULL, MRB_TT_PROC, 7 /* GC_RED */, MRB_FL_OBJ_IS_FROZEN, { &hook_irep }, NULL, { NULL }
+  };
+
+  struct RProc *hook = mrb_proc_new_cfunc(mrb, posthook);
+  int acc = 2;
+  memmove(ci->stack + acc, ci->stack, sizeof(mrb_value) * nregs);
+  ci->stack[0] = mrb_obj_value(hook);
+  ci->stack[1] = mrb_nil_value();
+  mrb_callinfo hook_ci = { 0, 0, ci->acc, &hook_caller, ci->stack, &hook_iseq[1], { NULL } };
+  ci = cipush(mrb, acc, acc, NULL, ci[0].proc, ci[0].mid, ci[0].argc);
+  ci->u.env = ci[-1].u.env;
+  ci[-1] = hook_ci;
+}
+
+/*
+ * If `posthook` is given, `posthook` will be called even if an
+ * exception or global jump occurs in `p`. Exception or global jump objects
+ * are stored in `mrb->c->stack[1]` and should be rethrown in `posthook`.
+ *
+ *    if (!mrb_nil_p(mrb->c->stack[1])) {
+ *      mrb_exc_raise(mrb, mrb->c->stack[1]);
+ *    }
+ *
+ * If you want to return the return value by `proc` as it is, please do
+ * `return mrb->c->stack[2]`.
+ *
+ * However, if `proc` is a C function, it will be ignored.
+ */
 mrb_value
-mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p)
+mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p, mrb_func_t posthook)
 {
   mrb_callinfo *ci = mrb->c->ci;
   mrb_int keep, nregs;
 
-  mrb->c->ci->stack[0] = self;
+  ci->stack[0] = self;
   mrb_vm_ci_proc_set(ci, p);
   if (MRB_PROC_CFUNC_P(p)) {
     return MRB_PROC_CFUNC(p)(mrb, self);
@@ -497,12 +557,17 @@ mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p)
   nregs = p->body.irep->nregs;
   if (ci->argc < 0) keep = 3;
   else keep = ci->argc + 2;
+  int extra = posthook ? (2 /* hook proc + errinfo */) : 0;
   if (nregs < keep) {
-    mrb_stack_extend(mrb, keep);
+    mrb_stack_extend(mrb, keep + extra);
   }
   else {
-    mrb_stack_extend(mrb, nregs);
-    stack_clear(mrb->c->ci->stack+keep, nregs-keep);
+    mrb_stack_extend(mrb, nregs + extra);
+    stack_clear(ci->stack+keep, nregs-keep + extra);
+  }
+
+  if (posthook) {
+    mrb_exec_irep_prepare_posthook(mrb, ci, (nregs < keep ? keep : nregs), posthook);
   }
 
   cipush(mrb, 0, 0, NULL, NULL, 0, 0);
@@ -573,7 +638,7 @@ mrb_f_send(mrb_state *mrb, mrb_value self)
     }
     return MRB_METHOD_CFUNC(m)(mrb, self);
   }
-  return mrb_exec_irep(mrb, self, MRB_METHOD_PROC(m));
+  return mrb_exec_irep(mrb, self, MRB_METHOD_PROC(m), NULL);
 }
 
 static mrb_value
@@ -760,7 +825,7 @@ mrb_yield_cont(mrb_state *mrb, mrb_value b, mrb_value self, mrb_int argc, const
   mrb->c->ci->stack[1] = mrb_ary_new_from_values(mrb, argc, argv);
   mrb->c->ci->stack[2] = mrb_nil_value();
   ci->argc = -1;
-  return mrb_exec_irep(mrb, self, p);
+  return mrb_exec_irep(mrb, self, p, NULL);
 }
 
 static struct RBreak*