Add some comments to better explain the source.

example/ex-array02.c

@@ -1,14 +1,31 @@
+// This is the same example as ex-array01.c
+// It uses some macros to simplify the writing of the code.
+// So it is a shorter version of the first example.
 #include "m-array.h"
 
-// Let's define an array of 'char *' named 'charp'
+// Let's define an array of 'char *' named 'array_charp'
 ARRAY_DEF (array_charp, char *)
-// Let's register globaly the oplist of array_charp
-#define M_OPL_array_charp_t() ARRAY_OPLIST(array_charp)
 
+// Let's register globaly the oplist of array_charp
+// This is done by defining a macro named M_OPL_ and the type
+// of the containern, like this:
+#define M_OPL_array_charp_t() ARRAY_OPLIST(array_charp)
+// An oplist is the interface published by the type.
+// It contains all exported methods of the type
+// (and which functions shall be called to handle them).
+// It is both an input of the ARRAY_DEF macro (the last argument)
+// if the type used to create the container has non-standard
+// requirements (like pretty much any C structure) and an output
+// (using ARRAY_OPLIST) which provides the updated oplist
+// which will handle the container itself.
 
 int main(void)
 {
-  // Create an array list 'al' of type array_charp_t
+  // Create an array list 'al' of type 'array_charp_t'
+  // M_LET will check if a global oplist has been registered
+  // with the name array_charp_t, and if it finds it, will
+  // define the type, initializes it and clears it after
+  // it disappears from the bracket:
   M_LET (al, array_charp_t) {
     // add elements to the array list
     array_charp_push_back (al,"C");
@@ -20,7 +37,16 @@ int main(void)
 
     // Display contents of al
     printf("Original contents of al: ");
-    // For each element of the array al
+    // M_EACH is a macro which iterates over a container.
+    // It first argument is the name of the created variable
+    // which will be a pointer to one element of the container,
+    // al is the container to iterate,
+    // the last argument is either the type of the container
+    // (if a global oplist has been registered) or is the oplist
+    // of the container (if none).
+    // Indeed the macro needs to access the methods of the container
+    // to iterate over the container.
+    // So for each element of the array al
     for M_EACH(element, al, array_charp_t) {
         printf ("%s ", *element);
     }