Add a Range datatype with creation methods like `5:to(10)` and

modification methods like `range:by(2)` or `range:reversed()`

1 files changed, 58 insertions, 0 deletions

diff --git a/builtins/range.c b/builtins/range.c
new file mode 100644
index 00000000..ced2a26f
--- /dev/null
+++ b/builtins/range.c
@@ -0,0 +1,58 @@
+// Functions that operate on numeric ranges
+
+#include <ctype.h>
+#include <err.h>
+#include <gc.h>
+#include <gc/cord.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/param.h>
+
+#include "types.h"
+#include "util.h"
+
+
+static int32_t Range$compare(const Range_t *x, const Range_t *y, const TypeInfo *type)
+{
+    (void)type;
+    int32_t diff = (x->first > y->first) - (x->first < y->first);
+    if (diff != 0) return diff;
+    diff = (x->last > y->last) - (x->last < y->last);
+    if (diff != 0) return diff;
+    return (x->step > y->step) - (x->step < y->step);
+}
+
+static bool Range$equal(const Range_t *x, const Range_t *y, const TypeInfo *type)
+{
+    (void)type;
+    return (x->first == y->first) && (x->last == y->last) && (x->step == y->step);
+}
+
+static CORD Range$as_text(const Range_t *r, bool use_color, const TypeInfo *type)
+{
+    (void)type;
+    if (!r) return "Range";
+
+    return CORD_asprintf(use_color ? "\x1b[0;1mRange\x1b[m(first=\x1b[35m%ld\x1b[m, last=\x1b[35m%ld\x1b[m, step=\x1b[35m%ld\x1b[m)"
+                         : "Range(first=%ld, last=%ld, step=%ld)", r->first, r->last, r->step);
+}
+
+public Range_t Range$reversed(Range_t r)
+{
+    return (Range_t){r.last, r.first, -r.step};
+}
+
+public Range_t Range$by(Range_t r, int64_t step)
+{
+    return (Range_t){r.first, r.last, step*r.step};
+}
+
+public const TypeInfo Range = {sizeof(Range_t), __alignof(Range_t), {.tag=CustomInfo, .CustomInfo={
+    .as_text=(void*)Range$as_text,
+    .compare=(void*)Range$compare,
+    .equal=(void*)Range$equal,
+}}};
+
+// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0