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example/ex-grep01.c

@@ -3,30 +3,50 @@
 #include "m-array.h"
 #include "m-dict.h"
 
+// Define an array of size_t
 ARRAY_DEF(array_size, size_t)
+// Register the oplist of this array globaly
 #define M_OPL_array_size_t() ARRAY_OPLIST(array_size)
+
+// Define a dictionary (hashmap) of string_t to array of size_t
 DICT_DEF2(map_pos, string_t, array_size_t)
+// Register the oplist of this dictionary (hashmap)
 #define M_OPL_map_pos_t() DICT_OPLIST(map_pos, STRING_OPLIST, ARRAY_OPLIST(array_size))
 
 int main(int argc, const char *argv[])
 {
-   if (argc == 2) {
-     M_LET(word, string_t)
-     M_LET(positions, map_pos_t) {
-        FILE *f = fopen(argv[1], "rt");
-        if (!f) return 1;
-        while (string_fget_word(word, " \t\n\r\"(),=", f)) {
-          array_size_t *array = map_pos_get_at(positions, word);
-          array_size_push_back(*array, (size_t)ftell(f) - string_size(word));
-        }
-        fclose(f);
+   if (argc != 2) {
+      printf("USAGE: %s filename\n", argv[0]);
+      exit(0);
+   }
 
-        for M_EACH(pair, positions, map_pos_t) {
+   // Define word as a string_t
+   M_LET(word, string_t)
+   // Define positions as a map of string_t-->array of size_t
+   M_LET(positions, map_pos_t) {
+      // Open the file
+      FILE *f = fopen(argv[1], "rt");
+      if (!f) return 1;
+
+      // While it reads some word from the file
+      while (string_fget_word(word, " \t\n\r\"(),=", f)) {
+         // Get the reference to this word in the dictionnary (or create it if needed)
+         array_size_t *array = map_pos_get_at(positions, word);
+         // Push the new offset to this word in the associated array
+         array_size_push_back(*array, (size_t)ftell(f) - string_size(word));
+      }
+
+      // Close the file
+      fclose(f);
+
+      // Print the words and where they are:
+      for M_EACH(pair, positions, map_pos_t) {
          string_fputs(stdout, pair->key);
          for M_EACH(pos, pair->value, array_size_t)
             printf(" %zu", *pos);
          printf("\n");
-        }
-     }
-   }
+         }
+      } // All created objects are destroyed beyond this point
+
+   return 0;
 }