Adding macro M_CHAIN_OBJ

README.md

@@ -6843,7 +6843,7 @@ This is equivalent to C++ construct:
 
         void type() : field1(), field2() { rest of constructor }
 
-M_CHAIN_INIT shall be the first instructions of the constructor function.
+M_CHAIN_INIT / M_CHAIN_OBJ shall be the first instructions of the constructor function.
 
 Example:
 
@@ -6856,6 +6856,44 @@ Example:
         }
 
 
+##### M\_CHAIN\_OBJ(name, oplist, var [, value])
+
+This macro executes the initialization method if 'var' to initialize it then
+registers the execution of its CLEAR method if an exception is triggered
+(and if the property NOCLEAR of the oplist is not defined)
+until the further closing brace of the next block of instruction.
+If exception are not enabled, it simply executes the initialization method.
+
+The initialization method being used is :
+
+* INIT method if there is no value
+* INIT\_SET method if there is a value which is not between parenthesis
+* INIT\_WITH method if there is a value which is between parenthesis.
+
+name shall a unique identifier in the current block.
+It can be chained multiple times to register multiple registrations.
+
+Therefore it enables support for chaining
+initialization at the begining of a constructor for the fields of the constructed
+object so that even if the constructor failed and throw an exception,
+the fields of the constructed object are properly cleared.
+
+This is equivalent to C++ construct:
+
+        void type() : field1(), field2() { rest of constructor }
+
+M_CHAIN_INIT / M_CHAIN_OBJ shall be the first instructions of the constructor function.
+
+Example:
+
+        void struct_init_set(struct_t d, struct_t s)
+        {
+          M_CHAIN_OBJ(s1, STRING_OPLIST, d->s1, s->s1)
+          M_CHAIN_OBJ(s2, STRING_OPLIST, d->s2, s->s2)
+          M_CHAIN_OBJ(nu, M_BASIC_OPLIST, d->num, s->num) { }
+        }
+
+
 #### Memory / Error macros
 
 All these macro can be overridden before including the header m-core.h

m-core.h

@@ -4387,9 +4387,9 @@ m_core_parse2_enum (const char str[], const char **endptr)
   the fields of the constructed object are properly cleared.
   This is equivalent to C++ construct: void type() : field1(), field2() { rest of constructor }
   M_CHAIN_INIT shall be the first instruction of the init function.
-  First argument is the initialization code.
-  Second argument is the clear code.
-  The clear code is only executed on exception.
+  Second argument is the initialization code.
+  Third argument is the clear code.
+  The clear code is *only* executed on exception.
   USAGE:
     void init_function(struct_t s) {
       M_CHAIN_INIT(name, string_init(s->str), string_clear(s->str)) {
@@ -4408,6 +4408,61 @@ m_core_parse2_enum (const char str[], const char **endptr)
           for( (void) 0; cont; cont = false)
 
 
+/* If exceptions are activated, M_CHAIN_OBJ enables support for chaining
+  initialization at the begining of a constructor for the fields of the constructed
+  object so that even if the constructor failed and throw an exception,
+  the fields of the constructed object are properly cleared.
+  This is equivalent to M_CHAIN_INIT except it takes an oplist.
+  This is equivalent to C++ construct: void type() : field1(), field2() { rest of constructor }
+  M_CHAIN_OBJ shall be the first instruction of the init function except
+  it can be freely mixed with M_CHAIN_INIT
+  First argument is a name identifier.
+  Second argument is the oplist of the variable to initialize.
+  Third argument is the variable to initialize.
+  Optional fourth argument is the value to use for initialization.
+  If there is no value, it will initialize using the INIT method.
+  Otherwise, if there is no parenthesis around the value, it will use the INIT_SET method.
+  Otherwise the INIT_WITH method.
+  The clear code is *only* executed on exception.
+  If the property NOCLEAR is defined for the object,
+  it won't generate an exception handler at all even if exceptions are activated,
+  and will only initialize the object.
+  USAGE:
+    void init_function(struct_t s) {
+      M_CHAIN_OBJ(name, STRING_OPLIST, s->str ) {
+        // Rest of initialization code
+      }
+    }
+ */
+#define M_CHAIN_OBJ(name, oplist, ...)                                        \
+  M_BY_NARGS( M_IF(M_GET_PROPERTY(oplist, NOCLEAR))(M_CHAIN_OBJ_A, M_CHAIN_OBJ_B), __VA_ARGS__) \
+  (name, oplist, __VA_ARGS__)
+// Need to define an exception handler. Use of M_CHAIN_INIT
+#define M_CHAIN_OBJ_B__NARGS_1(name, oplist, var)                             \
+  M_CHAIN_INIT( name, M_CALL_INIT(oplist, var), M_CALL_CLEAR(oplist, var) )
+#define M_CHAIN_OBJ_B__NARGS_2(name, oplist, var, value)                      \
+  M_IF(M_PARENTHESIS_P(value))(M_CHAIN_OBJ_B__NARGS_2_WITH, M_CHAIN_OBJ_B__NARGS_2_SET) \
+  (name, oplist, var, value)
+#define M_CHAIN_OBJ_B__NARGS_2_WITH(name, oplist, var, value)                 \
+  M_CHAIN_INIT( name, M_CALL_INIT_WITH(oplist, var, value), M_CALL_CLEAR(oplist, var) )
+#define M_CHAIN_OBJ_B__NARGS_2_SET(name, oplist, var, value)                  \
+  M_CHAIN_INIT( name, M_CALL_INIT_SET(oplist, var, value), M_CALL_CLEAR(oplist, var) )
+// No need to define an exception handler. Just call the INIT function.
+#define M_CHAIN_OBJ_A__NARGS_1(name, oplist, var)                             \
+  M_CHAIN_FOR(name, M_CALL_INIT(oplist, var) )
+#define M_CHAIN_OBJ_A__NARGS_2(name, oplist, var, value)                      \
+  M_CHAIN_FOR(name,                                                           \
+      M_IF(M_PARENTHESIS_P(value))(M_CALL_INIT_WITH, M_CALL_INIT_SET)         \
+      (oplist, var, value) )
+// Execute the 'init' function in a for loop construct
+#define M_CHAIN_FOR(name,  init )                                             \
+  M_CHAIN_FOR_B(M_C(m_var_, name), init)
+#define M_CHAIN_FOR_B(cont, init)                                             \
+  for(bool cont = true; cont; cont = false)                                   \
+      for( init; cont ; cont = false)                                         \
+          for( (void) 0; cont; cont = false)
+
+
 /* Declare a variable, initialize it, continue if the initialization succeeds,
    and clears the variable afterwards.
    Otherwise, stop the execution and execute else_code if defined.

tests/test-mtry.c

@@ -488,6 +488,27 @@ static void struct_init_set(struct_t x, const struct_t y)
   }
 }
 
+static void struct_initb(struct_t x)
+{
+  M_CHAIN_OBJ(o1, TESTOBJ_OPLIST, x->o1)
+  M_CHAIN_OBJ(o2, TESTOBJ_OPLIST, x->o2)
+  M_CHAIN_OBJ(o3, M_BASIC_OPLIST, x->num) {
+    if (++g_flow == g_throw) M_THROW(1);
+  }
+}
+
+static void struct_init_setb(struct_t x, const struct_t y)
+{
+  M_CHAIN_OBJ(o1, TESTOBJ_OPLIST, x->o1, y->o1) {
+    // Throw within the constructor (object partially constructed)
+    if (++g_flow == g_throw) M_THROW(1);
+    M_CHAIN_OBJ(o2, TESTOBJ_OPLIST, x->o2, y->o2)
+    M_CHAIN_OBJ(o3, M_BASIC_OPLIST, x->num, y->num) {
+      if (++g_flow == g_throw) M_THROW(1);
+    }
+  }
+}
+
 static void struct_clear(struct_t x)
 {
   testobj_clear(x->o1);
@@ -496,7 +517,7 @@ static void struct_clear(struct_t x)
 
 #define M_OPL_struct_t() M_CLASSIC_OPLIST(struct)
 
-static void test4(void)
+static void test4a(void)
 {
   g_flow = 0;
   g_throw = 4;
@@ -552,6 +573,65 @@ static void test4(void)
   }
 }
 
+#define STRUCTB_OPLIST                                        \
+  (INIT(struct_initb), INIT_SET(struct_init_setb), CLEAR(struct_clear), TYPE(struct_t))
+
+static void test4b(void)
+{
+  g_flow = 0;
+  g_throw = 4;
+  M_TRY(main) {
+    assert(++g_flow == 1);
+    M_LET(a, STRUCTB_OPLIST) {
+      assert(++g_flow == 3);
+      M_LET( (b, a), STRUCTB_OPLIST) {
+        assert(false);
+      }
+    }
+  } M_CATCH(main, 0) {
+    assert(++g_flow == 5);
+  }
+
+  g_flow = 0;
+  g_throw = 5;
+  M_TRY(main) {
+    assert(++g_flow == 1);
+    M_LET(a, STRUCTB_OPLIST) {
+      assert(++g_flow == 3);
+      M_LET( (b, a), STRUCTB_OPLIST) {
+        assert(false);
+      }
+    }
+  } M_CATCH(main, 0) {
+    assert(++g_flow == 6);
+  }
+
+  g_flow = 0;
+  g_throw = 2;
+  M_TRY(main) {
+    assert(++g_flow == 1);
+    M_LET(a, STRUCTB_OPLIST) {
+      assert(false);
+    }
+  } M_CATCH(main, 0) {
+    assert(++g_flow == 3);
+  }
+
+  g_flow = 0;
+  g_throw = 0;
+  M_TRY(main) {
+    assert(++g_flow == 1);
+    M_LET(a, STRUCTB_OPLIST) {
+      assert(++g_flow == 3);
+      M_LET( (b, a), STRUCTB_OPLIST) {
+        assert(++g_flow == 6);
+      }
+    }
+  } M_CATCH(main, 0) {
+    assert(false);
+  }
+}
+
 static void test_final(void)
 {
   // Throw without a try block shall raise the M_RAISE_FATAL macro
@@ -568,7 +648,8 @@ int main(void)
   test1();
   test2();
   test3();
-  test4();
+  test4a();
+  test4b();
   testobj_final_check();
   test_final();
   exit(1); // Shall not be reached.