Added .count to c_forfilter() algorithm. Updated prime.c example, and added forloops.c example.

4 files changed, 100 insertions, 18 deletions

diff --git a/docs/ccommon_api.md b/docs/ccommon_api.md
index 1b364e58..39200907 100644
--- a/docs/ccommon_api.md
+++ b/docs/ccommon_api.md
@@ -139,7 +139,7 @@ from a `c_auto` scope:
         ...
     } // for
 ```
-## Loop abstaction macros
+## Loop abstraction macros
 
 ### c_forlist
 Iterate compound literal array elements. Additional to `i.ref`, you can access `i.data`, `i.size`, and `i.index` of the input list/element.
@@ -193,7 +193,7 @@ c_forpair (id, count, csmap_ii, map)
 ```
 
 ### c_forloop
-Abstaction for iterating sequence of numbers. Like python's **for** *i* **in** *range()* loop.
+Abstraction for iterating sequence of numbers. Like python's **for** *i* **in** *range()* loop.
 
 | Usage                                       | Python equivalent                    |
 |:--------------------------------------------|:-------------------------------------|
@@ -229,7 +229,7 @@ Iterate containers with stop-criteria and chained range filtering.
 | `c_flt_dropwhile(it, predicate)`  | Drop items until predicate is false  |
 | `c_flt_takewhile(it, predicate)`  | Take items until predicate is false  |
 
-`it.index` holds the index of the source item.
+`it.index` holds the index of the source item, and `it.count` the current number of items taken.
 ```c
 #define i_type IVec
 #define i_val int
@@ -275,16 +275,16 @@ void        crange_next(crange_iter* it);
 // 1. All primes less than 32:
 crange r1 = crange_from(3, 32, 2);
 printf("2"); // first prime
-c_forfilter (i, crange, r1, 
-                isPrime(*i.ref))
+c_forfilter (i, crange, r1 
+              , isPrime(*i.ref))
     printf(" %lld", *i.ref);
 // 2 3 5 7 11 13 17 19 23 29 31
 
 // 2. The 11 first primes:
 crange r2 = crange_make(3, INTMAX_MAX, 2);
 printf("2");
-c_forfilter (i, crange, r2, 
-                isPrime(*i.ref)
+c_forfilter (i, crange, r2 
+              , isPrime(*i.ref)
               , c_flt_take(10))
     printf(" %lld", *i.ref);
 // 2 3 5 7 11 13 17 19 23 29 31
@@ -313,7 +313,7 @@ c_erase_if(k, cvec_i, *k.ref < 100);
 | `c_new (type, value)`          | Move value to a new object on the heap  |
 | `c_alloc (type)`               | `(type *) c_malloc(sizeof(type))`       |
 | `c_alloc_n (type, N)`          | `(type *) c_malloc((N)*sizeof(type))`   |
-| `c_drop (ctype, &c1, ..., &cN)` | `ctype_drop(&c1); ... ctype_drop(&cN)`    |
+| `c_drop (ctype, &c1, ..., &cN)` | `ctype_drop(&c1); ... ctype_drop(&cN)` |
 | `c_make(type){value...}`       | `(type){value...}` // c++ compatability |
 
 ```c
@@ -329,7 +329,7 @@ c_drop(cstr, &a, &b);
 ```
 
 ### General predefined template parameter functions
-```
+```c
 int         c_default_cmp(const Type*, const Type*);
 Type        c_default_clone(Type val);           // simple copy
 Type        c_default_toraw(const Type* val);    // dereference val
diff --git a/examples/forloops.c b/examples/forloops.c
new file mode 100644
index 00000000..f119e33a
--- /dev/null
+++ b/examples/forloops.c
@@ -0,0 +1,80 @@
+#include <stdio.h>

+

+#define i_type IVec

+#define i_val int

+#include <stc/cstack.h>

+

+#define i_type IMap

+#define i_key int

+#define i_val int

+#include <stc/cmap.h>

+

+

+int main()

+{

+    puts("c_forloop:");

+    c_forloop (30) printf(" xx");

+    puts("");

+

+    c_forloop (i, 30) printf(" %lld", i);

+    puts("");

+

+    c_forloop (i, 30, 60) printf(" %lld", i);

+    puts("");

+

+    c_forloop (i, 30, 90, 2) printf(" %lld", i);

+

+

+    puts("\n\nc_forlist:");

+    c_forlist (i, int, {12, 23, 453, 65, 676})

+        printf(" %d", *i.ref);

+    puts("");

+

+    c_forlist (i, const char*, {"12", "23", "453", "65", "676"})

+        printf(" %s", *i.ref);

+    puts("");

+

+    c_forlist (i, const char*, {"12", "23", "453", "65", "676"})

+        printf(" %s", i.data[i.size - 1 - i.index]);

+

+

+    c_auto (IVec, vec) 

+    c_auto (IMap, map)

+    {

+        c_forlist (i, int, {12, 23, 453, 65, 113, 215, 676, 34, 67, 20, 27, 66, 189, 45, 280, 199})

+            IVec_push(&vec, *i.ref);

+

+        c_forlist (i, IMap_value, {{12, 23}, {453, 65}, {676, 123}, {34, 67}})

+            IMap_push(&map, *i.ref);

+

+        puts("\n\nc_foreach:");

+        c_foreach (i, IVec, vec)

+            printf(" %d", *i.ref);

+        puts("");

+

+        c_foreach (i, IMap, map)

+            printf(" (%d %d)", i.ref->first, i.ref->second);

+

+        puts("\n\nc_forpair:");

+        c_forpair (key, val, IMap, map)

+            printf(" (%d %d)", *_.key, *_.val);

+

+        puts("\n\nc_forwhile:");

+        c_forwhile (i, IVec, vec, i.index < 3)

+            printf(" %d", *i.ref);

+

+        #define isOdd(i) (*i.ref & 1)

+

+        puts("\n\nc_forfilter:");

+        c_forfilter (i, IVec, vec, 

+                        c_flt_dropwhile(i, *i.ref != 65)

+                     && c_flt_takewhile(i, *i.ref != 280)

+                     && c_flt_dropwhile(i, isOdd(i))

+                     && isOdd(i)

+                     && c_flt_drop(i, 2)

+                      , c_flt_take(i, 1))

+            printf(" %d", *i.ref);

+        puts("");

+        // 189

+    }

+}

diff --git a/examples/prime.c b/examples/prime.c
index 12d33a9e..613048bf 100644
--- a/examples/prime.c
+++ b/examples/prime.c
@@ -33,16 +33,18 @@ int main(void)
         clock_t t2 = clock();
 
         printf("number of primes: %" PRIuMAX ", time: %f\n", np, (t2 - t1) / (float)CLOCKS_PER_SEC);
+        puts("Show all the primes in the range [2, 1000):");
         printf("2");
-        for (size_t i = 3; i < 1000; i += 2)
-            if (cbits_test(&primes, i>>1)) printf(" %" PRIuMAX "", i);
+        c_forloop (i, 3, 1000, 2)
+            if (cbits_test(&primes, i>>1)) printf(" %lld", i);
         puts("");
 
-        int k = 20;
-        c_forloop (i, n-1, 1, -2) {
-            if (k == 0) break;
-            else if (cbits_test(&primes, i>>1)) printf("%lld\n", i), k--;
+        puts("Show the last 50 primes using a temporary crange generator:");
+        c_forfilter (i, crange, *(crange[]){crange_make(n - 1, 0, -2)}
+                      , cbits_test(&primes, *i.ref>>1)
+                      , c_flt_take(i, 50)) {
+            printf("%lld ", *i.ref);
+            if (i.count % 10 == 0) puts("");
         }
-        puts("");
     }
 }
diff --git a/include/stc/ccommon.h b/include/stc/ccommon.h
index 2edab5bc..1961833b 100644
--- a/include/stc/ccommon.h
+++ b/include/stc/ccommon.h
@@ -176,11 +176,11 @@ STC_INLINE char* c_strnstrn(const char *s, const char *needle,
 #define c_forfilter5(it, C, cnt, filter, whilepred) \
     c_forfilter_s(it, C, C##_begin(&cnt), filter) if (!(whilepred)) break; else
 #define c_forfilter_s(it, C, start, filter) \
-    c_foreach_s(it, C, start) if (!(filter)) ; else
+    c_foreach_s(it, C, start) if (!((filter) && ++it.count)) ; else
 
 #define c_foreach_s(i, C, start) \
     for (struct {C##_iter it; C##_value *ref; \
-                 uint32_t s1[c_FLT_STACK+1], index; \
+                 uint32_t s1[c_FLT_STACK], index, count; \
                  uint8_t s2[c_FLT_STACK], s1top, s2top;} \
          i = {.it=start, .ref=i.it.ref}; i.it.ref \
          ; C##_next(&i.it), i.ref = i.it.ref, ++i.index, i.s1top=0, i.s2top=0)