From 14adfd873e4259762c580692b2b725e220fb7ed2 Mon Sep 17 00:00:00 2001
From: Louis Rubet <louis@rubet.fr>
Date: Fri, 21 Apr 2017 13:58:44 +0200
Subject: [PATCH] #34: refactored stack::pop_back() for easier code

---
 src/rpn-binary.h  |  3 +--
 src/rpn-branch.h  |  2 +-
 src/rpn-general.h | 13 ++++---------
 src/rpn-program.h |  9 ++++-----
 src/rpn-real.h    | 36 ++++++++++++------------------------
 src/rpn-stack.h   | 21 ++++++++++-----------
 src/rpn-store.h   | 13 +++++--------
 src/rpn-string.h  |  6 ++----
 src/rpn-test.h    | 27 +++++++++------------------
 src/stack.h       |  8 +++++++-
 10 files changed, 55 insertions(+), 83 deletions(-)

diff --git a/src/rpn-binary.h b/src/rpn-binary.h
index 7b25510..db9e57b 100644
--- a/src/rpn-binary.h
+++ b/src/rpn-binary.h
@@ -23,8 +23,7 @@ void rtob()
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-    number* left = (number*)_stack->back();
-    _stack->pop_back();
+    number* left = (number*)_stack->pop_back();
 
     binary bin;
     bin.set(mpfr_get_sj(&left->_value.mpfr, s_mpfr_rnd));
diff --git a/src/rpn-branch.h b/src/rpn-branch.h
index 3cddf11..3bde523 100644
--- a/src/rpn-branch.h
+++ b/src/rpn-branch.h
@@ -10,7 +10,7 @@ int rpn_if(branch& myobj)
         myobj.arg1 = 1;
     else
         myobj.arg1 = 0;
-    _stack->pop_back();
+    (void)_stack->pop_back();
     return -1;
 }
 
diff --git a/src/rpn-general.h b/src/rpn-general.h
index 942a885..062e52f 100644
--- a/src/rpn-general.h
+++ b/src/rpn-general.h
@@ -16,9 +16,7 @@ void verbose()
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-    int verbose = int(((number*)_stack->back())->_value);
-    _stack->pop_back();
-
+    int verbose = int(((number*)_stack->pop_back())->_value);
     g_verbose = verbose;
 }
 
@@ -84,8 +82,7 @@ void std()
     {
         ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-        int precision = int(((number*)_stack->back())->_value);
-        _stack->pop_back();
+        int precision = int(((number*)_stack->pop_back())->_value);
         number::s_default_precision = int(precision);
     }
 
@@ -103,8 +100,7 @@ void fix()
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-    int precision = int(((number*)_stack->back())->_value);
-    _stack->pop_back();
+    int precision = int(((number*)_stack->pop_back())->_value);
     number::s_current_precision = int(precision);
 
     number::s_mode = number::fix;
@@ -120,8 +116,7 @@ void sci()
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-    int precision = int(((number*)_stack->back())->_value);
-    _stack->pop_back();
+    int precision = int(((number*)_stack->pop_back())->_value);
     number::s_current_precision = int(precision);
 
     number::s_mode = number::sci;
diff --git a/src/rpn-program.h b/src/rpn-program.h
index 11e205b..230ed7d 100644
--- a/src/rpn-program.h
+++ b/src/rpn-program.h
@@ -22,13 +22,13 @@ void eval(void)
             if (type == cmd_program)
             {
                 prog_text = ((oprogram*)obj)->_value;
-                _stack->pop_back();
+                (void)_stack->pop_back();
                 run_prog = true;
             }
             else
             {
                 // else recall variable (i.e. stack its content)
-                _stack->pop_back();
+                (void)_stack->pop_back();
                 _stack->push_back(obj, size, type);
             }
         }
@@ -38,8 +38,7 @@ void eval(void)
     else if (IS_ARG_TYPE(0, cmd_program))
     {
         // eval a program
-        prog_text = ((oprogram*)_stack->back())->_value;
-        _stack->pop_back();
+        prog_text = ((oprogram*)_stack->pop_back())->_value;
         run_prog = true;
     }
     else
@@ -125,7 +124,7 @@ int inprog(branch& myobj)
     for (unsigned int i = myobj.arg1 + count_symbols; i > myobj.arg1; i--)
     {
         local_heap.add(string(((symbol*)seq_obj(i))->_value), _stack->get_obj(0), _stack->get_len(0), _stack->get_type(0));
-        _stack->pop_back();
+        (void)_stack->pop_back();
     }
 
     // run the program
diff --git a/src/rpn-real.h b/src/rpn-real.h
index 56ea95a..5955f83 100644
--- a/src/rpn-real.h
+++ b/src/rpn-real.h
@@ -7,8 +7,7 @@ void plus()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-        number* right = (number*)_stack->back();
-        _stack->pop_back();
+        number* right = (number*)_stack->pop_back();
         number* left = (number*)_stack->back();
         CHECK_MPFR(mpfr_add(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
     }
@@ -17,8 +16,7 @@ void plus()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_binary);
         
-        binary* right = (binary*)_stack->back();
-        _stack->pop_back();
+        binary* right = (binary*)_stack->pop_back();
         binary* left = (binary*)_stack->back();
         left->_value += right->_value;
     }
@@ -35,8 +33,7 @@ void minus()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-        number* right = (number*)_stack->back();
-        _stack->pop_back();
+        number* right = (number*)_stack->pop_back();
         number* left = (number*)_stack->back();
         CHECK_MPFR(mpfr_sub(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
     }
@@ -45,8 +42,7 @@ void minus()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_binary);
 
-        binary* right = (binary*)_stack->back();
-        _stack->pop_back();
+        binary* right = (binary*)_stack->pop_back();
         binary* left = (binary*)_stack->back();
         left->_value -= right->_value;
     }
@@ -61,8 +57,7 @@ void mul()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-        number* right = (number*)_stack->back();
-        _stack->pop_back();
+        number* right = (number*)_stack->pop_back();
         number* left = (number*)_stack->back();
         CHECK_MPFR(mpfr_mul(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
     }
@@ -71,8 +66,7 @@ void mul()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_binary);
 
-        binary* right = (binary*)_stack->back();
-        _stack->pop_back();
+        binary* right = (binary*)_stack->pop_back();
         binary* left = (binary*)_stack->back();
         left->_value *= right->_value;
     }
@@ -89,8 +83,7 @@ void div()
     {
         ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-        number* right = (number*)_stack->back();
-        _stack->pop_back();
+        number* right = (number*)_stack->pop_back();
         number* left = (number*)_stack->back();
         CHECK_MPFR(mpfr_div(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
     }
@@ -104,8 +97,7 @@ void div()
         }
         else
         {
-            binary* right = (binary*)_stack->back();
-            _stack->pop_back();
+            binary* right = (binary*)_stack->pop_back();
             binary* left = (binary*)_stack->back();
             left->_value /= right->_value;
         }
@@ -146,8 +138,7 @@ void purcent()
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right = (number*)_stack->back();
-    _stack->pop_back();
+    number* right = (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     CHECK_MPFR(mpfr_mul(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
@@ -160,8 +151,7 @@ void purcentCH()
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right = (number*)_stack->back();
-    _stack->pop_back();
+    number* right = (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     CHECK_MPFR(mpfr_mul_si(&right->_value.mpfr, &right->_value.mpfr, 100L, s_mpfr_rnd));
@@ -174,8 +164,7 @@ void power()
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right = (number*)_stack->back();
-    _stack->pop_back();
+    number* right = (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
     CHECK_MPFR(mpfr_pow(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
 }
@@ -204,8 +193,7 @@ void modulo()
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right = (number*)_stack->back();
-    _stack->pop_back();
+    number* right = (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     CHECK_MPFR(mpfr_fmod(&left->_value.mpfr, &left->_value.mpfr, &right->_value.mpfr, s_mpfr_rnd));
diff --git a/src/rpn-stack.h b/src/rpn-stack.h
index b17ca1a..15945a1 100644
--- a/src/rpn-stack.h
+++ b/src/rpn-stack.h
@@ -4,8 +4,8 @@ void swap(void)
     MIN_ARGUMENTS(2);
     _stack->copy_obj_to_local(0, 0);
     _stack->copy_obj_to_local(1, 1);
-    _stack->pop_back();
-    _stack->pop_back();
+    (void)_stack->pop_back();
+    (void)_stack->pop_back();
     _stack->push_obj_from_local(0);
     _stack->push_obj_from_local(1);
 }
@@ -13,20 +13,20 @@ void swap(void)
 void drop(void)
 {
     MIN_ARGUMENTS(1);
-    _stack->pop_back();
+    (void)_stack->pop_back();
 }
 
 void drop2(void)
 {
     MIN_ARGUMENTS(2);
-    _stack->pop_back();
-    _stack->pop_back();
+    (void)_stack->pop_back();
+    (void)_stack->pop_back();
 }
 
 void erase(void)
 {
     while(_stack->size()>0)
-        _stack->pop_back();
+        (void)_stack->pop_back();
 }
 
 void dup(void)
@@ -50,8 +50,7 @@ void pick(void)
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
 
-    unsigned int to_pick = (unsigned int)int(((number*)_stack->back())->_value);
-    _stack->pop_back();
+    unsigned int to_pick = (unsigned int)int(((number*)_stack->pop_back())->_value);
 
     // treat stack depth errors
     if ((to_pick == 0) || (to_pick > _stack->size()))
@@ -69,9 +68,9 @@ void rot(void)
     _stack->copy_obj_to_local(0, 0);
     _stack->copy_obj_to_local(1, 1);
     _stack->copy_obj_to_local(2, 2);
-    _stack->pop_back();
-    _stack->pop_back();
-    _stack->pop_back();
+    (void)_stack->pop_back();
+    (void)_stack->pop_back();
+    (void)_stack->pop_back();
     _stack->push_obj_from_local(1);
     _stack->push_obj_from_local(0);
     _stack->push_obj_from_local(2);
diff --git a/src/rpn-store.h b/src/rpn-store.h
index 61580d9..171f3ed 100644
--- a/src/rpn-store.h
+++ b/src/rpn-store.h
@@ -4,10 +4,9 @@ void sto(void)
     MIN_ARGUMENTS(2);
     ARG_MUST_BE_OF_TYPE(0, cmd_symbol);
 
-    string name(((symbol*)_stack->get_obj(0))->_value);
-    _stack->pop_back();
+    string name(((symbol*)_stack->pop_back())->_value);
     _global_heap->add(name, _stack->get_obj(0), _stack->get_len(0), _stack->get_type(0));
-    _stack->pop_back();
+    (void)_stack->pop_back();
 }
 
 void rcl(void)
@@ -26,7 +25,7 @@ void rcl(void)
             || ((_parent_local_heap != NULL) && (_parent_local_heap->get(variable, obj, size, type)))
             || _global_heap->get(variable, obj, size, type))
     {
-        _stack->pop_back();
+        (void)_stack->pop_back();
         _stack->push_back(obj, size, type);
     }
     else
@@ -57,8 +56,7 @@ void edit(void)
     }
 
     // re-write stack objet in a stream
-    ((object*)_stack->back())->show(out);
-    _stack->pop_back();
+    ((object*)_stack->pop_back())->show(out);
 
     // edit: stuff chars using readline facility
     string str = out.str();
@@ -100,7 +98,7 @@ void purge(void)
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_symbol);
 
-    string name(((symbol*)_stack->back())->_value);
+    string name(((symbol*)_stack->pop_back())->_value);
 
     // mind the order of heaps
     bool done = false;
@@ -114,7 +112,6 @@ void purge(void)
     else
         done = true;
 
-    _stack->pop_back();
     if (!done)
         ERR_CONTEXT(ret_unknown_variable);
 }
diff --git a/src/rpn-string.h b/src/rpn-string.h
index dbd7ec4..43bec79 100644
--- a/src/rpn-string.h
+++ b/src/rpn-string.h
@@ -7,8 +7,7 @@ void instr()
     {
         // write the object in stack(0) in a string and remove this obj
         stringstream out;
-        ((object*)_stack->back())->show(out);
-        _stack->pop_back();
+        ((object*)_stack->pop_back())->show(out);
 
         // reserve the correct size in stack
         _stack->push_back(NULL, out.str().size(), cmd_string, true);
@@ -24,8 +23,7 @@ void strout()
     MIN_ARGUMENTS(1);
     ARG_MUST_BE_OF_TYPE(0, cmd_string);
 
-    string entry(((ostring*)_stack->back())->_value);
-    _stack->pop_back();
+    string entry(((ostring*)_stack->pop_back())->_value);
 
     program prog;
 
diff --git a/src/rpn-test.h b/src/rpn-test.h
index 846feed..4ef1d4a 100644
--- a/src/rpn-test.h
+++ b/src/rpn-test.h
@@ -4,8 +4,7 @@ void sup(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) > 0)
@@ -20,8 +19,7 @@ void sup_eq(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) >= 0)
@@ -36,8 +34,7 @@ void inf(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) < 0)
@@ -52,8 +49,7 @@ void inf_eq(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) <= 0)
@@ -68,8 +64,7 @@ void diff(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) != 0)
@@ -84,8 +79,7 @@ void eq(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp(&left->_value.mpfr, &right->_value.mpfr) == 0)
@@ -100,8 +94,7 @@ void test_and(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if ((mpfr_cmp_si(&left->_value.mpfr, 0) == 0)
@@ -117,8 +110,7 @@ void test_or(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if ((mpfr_cmp_si(&left->_value.mpfr, 0) == 0)
@@ -134,8 +126,7 @@ void test_xor(void)
     ARG_MUST_BE_OF_TYPE(0, cmd_number);
     ARG_MUST_BE_OF_TYPE(1, cmd_number);
 
-    number* right =  (number*)_stack->back();
-    _stack->pop_back();
+    number* right =  (number*)_stack->pop_back();
     number* left = (number*)_stack->back();
 
     if (mpfr_cmp_si(&left->_value.mpfr, 0) == 0)
diff --git a/src/stack.h b/src/stack.h
index bd628a7..efab231 100644
--- a/src/stack.h
+++ b/src/stack.h
@@ -53,8 +53,10 @@ public:
         _current += size;
     }
 
-    void pop_back()
+    void* pop_back()
     {
+        void* back = NULL;
+
         if (_count > 0)
         {
             _current = _vpointer[_count - 1];
@@ -62,7 +64,11 @@ public:
             _vpointer.pop_back();
             _vtype.pop_back();
             _count--;
+
+            back = _current;
         }
+
+        return back;
     }
 
     unsigned int size()