Started refactor

src_v2/utils/fp.nim

@@ -0,0 +1,37 @@
+import std/sugar
+import fp/maybe
+import results
+
+func last*[T](xs: seq[T]): Maybe[T] =
+  if xs.len == 0:
+     nothing(T)
+  else:
+    just(xs[^1])
+
+template isSome*(self: Result): bool = self.isOk()
+template isNone*(self: Result): bool = self.isErr()
+
+proc findMaybe*[T](xs: seq[T], fn: T -> bool): Maybe[T] =
+  for x in xs:
+    if fn(x):
+      return Just(x)
+  return Nothing[T]()
+
+proc findMaybeFn*[T, B](fns: seq[T {.nimcall.} -> Maybe[B]], val: T): Maybe[B] =
+  for fn in fns:
+    let res = fn(val)
+    if res.isDefined():
+      return res
+  return Nothing[B]()
+
+proc notNegative*[int](x: Maybe[int]): Maybe[int] =
+  ## Maps nil object to nothing
+  x.filter(i => i >= 0)
+
+when isMainModule:
+  echo @[
+  (x: int) => (if x == 2: Just("foo") else: Nothing[string]()),
+  ].findMaybeFn(2)
+
+  assert last(@[1,2,3]) == just(3)
+  assert last[int](@[]) == nothing(int)