diff --git a/flag/flag.c b/flag/flag.c
index 41ff6cd..cd16497 100644
--- a/flag/flag.c
+++ b/flag/flag.c
@@ -1,7 +1,7 @@
+#include "flag.h"
 #include "../bstr/bstr.h"
 #include "../vec/vector.h"
 #include <stdbool.h>
-#include "flag.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -109,9 +109,7 @@ static bool arg_is_flag(bstr *arg) {
   return true;
 }
 
-bool flag_parsed(flag_Parser *p) {
-  return p->parsed;
-}
+bool flag_parsed(flag_Parser *p) { return p->parsed; }
 
 void flag_parse(flag_Parser *p) {
   for (int curr_arg_idx = 0; curr_arg_idx < p->argc; curr_arg_idx++) {
@@ -121,39 +119,70 @@ void flag_parse(flag_Parser *p) {
       continue;
     }
 
+    bstr flag_name, flag_value;
+    size_t sep_idx = 0;
+    if (bstr_index(&sep_idx, arg, bstr_new("=")) ||
+        bstr_index(&sep_idx, arg, bstr_new(":"))) {
+      flag_value = bstr_new(arg.cstr + sep_idx + 1);
+      flag_name = arg;
+      flag_name.len -= flag_value.len + 1;
+    } else {
+      flag_name = arg;
+      flag_value = bstr_new("");
+    }
+
     struct flag_flag *curr_flag = NULL;
     for (size_t j = 0; j < vec_len(p->flags); j++) {
       vec_get(p->flags, j, &curr_flag);
 
-      if (bstr_equal(arg, curr_flag->name)) {
-        if (++curr_arg_idx >= p->argc) {
-          break;
-        }
+      if (bstr_equal(flag_name, curr_flag->name)) {
+        char *flag_val = NULL;
+
+        if (flag_value.len == 0 && curr_flag->type != FLAG_BOOL) {
+          if (++curr_arg_idx >= p->argc) {
+            break;
+          }
 
-        char *flag_val = p->argv[curr_arg_idx];
+          flag_val = p->argv[curr_arg_idx];
+        } else {
+          flag_val = flag_value.cstr;
+        }
 
         switch (curr_flag->type) {
         case FLAG_BOOL:
-          curr_flag->bool_flag = true;
+          if (flag_value.len == 0) {
+            curr_flag->bool_flag = !curr_flag->bool_flag;
+          } else if (bstr_equal(flag_value, bstr_new("true"))) {
+            curr_flag->bool_flag = true;
+          } else if (bstr_equal(flag_value, bstr_new("false"))) {
+            curr_flag->bool_flag = false;
+          }
           break;
+
         case FLAG_STR:
           curr_flag->str_flag = flag_val;
           break;
+
         case FLAG_LONG:
           curr_flag->long_flag = strtol(flag_val, NULL, 10);
           break;
+
         case FLAG_ULONG:
           curr_flag->ulong_flag = strtoul(flag_val, NULL, 10);
           break;
+
         case FLAG_LONGLONG:
           curr_flag->longlong_flag = strtoll(flag_val, NULL, 10);
           break;
+
         case FLAG_ULONGLONG:
           curr_flag->ulonglong_flag = strtoull(flag_val, NULL, 10);
           break;
+
         case FLAG_DOUBLE:
           curr_flag->double_flag = strtod(flag_val, NULL);
           break;
+
         case FLAG_FLOAT:
           curr_flag->float_flag = strtof(flag_val, NULL);
           break;
diff --git a/flag/maintest.c b/flag/maintest.c
index 7f4d75a..a8c6368 100644
--- a/flag/maintest.c
+++ b/flag/maintest.c
@@ -4,7 +4,7 @@
 #include <string.h>
 
 int main(void) {
-  char *argv[] = {"--funnyno", "69420", "-pi", "3.14159265359", "--hello", "world"};
+  char *argv[] = {"--test=77", "--funnyno", "69420", "--is-true", "-pi", "3.14159265359", "--hello:world"};
   int argc = sizeof(argv) / sizeof(argv[0]);
 
   flag_Parser p = flag_new(argc, argv);
@@ -12,7 +12,9 @@ int main(void) {
   long *funny_num = flag_long(&p, "funnyno", 0, "the funny number");
   char **hello = flag_str(&p, "hello", "test", "says hello");
   double *pi = flag_double(&p, "pi", 0, "the number for pi");
-  assert(flag_nflags(&p) == 3);
+  long *test = flag_long(&p, "test", 99, "get number 99 or something else");
+  bool *is_true = flag_bool(&p, "is-true", false, "returns true when used");
+  assert(flag_nflags(&p) == 5);
 
   assert(flag_parsed(&p) == false);
   flag_parse(&p);
@@ -21,6 +23,8 @@ int main(void) {
   assert(*funny_num == 69420);
   assert(strcmp(*hello, "world") == 0);
   assert(*pi == 3.14159265359);
+  assert(*test == 77);
+  assert(*is_true);
 
   flag_free(&p);
   puts("test passed.");