Handle calls and operators following a .? chain

Fixes #3

questionable/chaining.nim

@@ -0,0 +1,33 @@
+import std/macros
+
+template `.?`*(option: typed, identifier: untyped{nkIdent}): untyped =
+  option ->? option.unsafeGet.identifier
+
+macro `.?`*(option: typed, infix: untyped{nkInfix}): untyped =
+  let left = infix[1]
+  infix[1] = quote do: `option`.?`left`
+  infix
+
+macro `.?`*(option: typed, bracket: untyped{nkBracketExpr}): untyped =
+  let left = bracket[0]
+  bracket[0] = quote do: `option`.?`left`
+  bracket
+
+macro `.?`*(option: typed, dot: untyped{nkDotExpr}): untyped =
+  let left = dot[0]
+  dot[0] = quote do: `option`.?`left`
+  dot
+
+macro `.?`*(option: typed, call: untyped{nkCall}): untyped =
+  let procedure = call[0]
+  if call.len > 1:
+    if procedure.kind == nnkDotExpr:
+      let (inner, outer) = (procedure[0], procedure[1])
+      call[0] = outer
+      call.insert(1, quote do: `option`.?`inner`)
+      call
+    else:
+      call.insert(1, quote do: `option`.unsafeGet)
+      quote do: `option` ->? `call`
+  else:
+      quote do: `option`.?`procedure`

questionable/operators.nim

@@ -0,0 +1,12 @@
+template liftUnary*(T: type, operator: untyped) =
+
+  template `operator`*(a: T): untyped =
+    a ->? `operator`(a.unsafeGet())
+
+template liftBinary*(T: type, operator: untyped) =
+
+  template `operator`*(a: T, b: T): untyped =
+    (a, b) ->? `operator`(a.unsafeGet, b.unsafeGet)
+
+  template `operator`*(a: T, b: typed): untyped =
+    a ->? `operator`(a.unsafeGet(), b)

questionable/options.nim

@@ -1,54 +1,39 @@
 import std/options
+import ./chaining
+import ./operators
 
 include ./errorban
 
 export options
+export chaining
 
 template `?`*(T: typed): type Option[T] =
   Option[T]
 
-template `.?`*(option: ?typed, field: untyped{nkIdent}): ?untyped =
+template `->?`*(option: ?typed, expression: untyped): untyped =
-  type T = type option.get.field
+  type T = type expression
   if option.isSome:
-    option.unsafeGet().field.some
+    expression.some
   else:
     T.none
 
+template `->?`*(options: (?typed, ?typed), expression: untyped): untyped =
+  type T = type expression
+  if options[0].isSome and options[1].isSome:
+    expression.some
+  else:
+    T.none
+
+template `=?`*[T](name: untyped{nkIdent}, option: ?T): bool =
+  template name: T {.used.} = option.unsafeGet()
+  option.isSome
+
 template `|?`*[T](option: ?T, fallback: T): T =
   if option.isSome:
     option.unsafeGet()
   else:
     fallback
 
-template `=?`*[T](name: untyped{nkIdent}, option: ?T): bool =
-  template name: T {.used.} = option.unsafeGet()
-  option.isSome
-
-template liftUnary(_: type Option, operator: untyped) =
-
-  template `operator`*(a: ?typed): ?typed =
-    type T {.used.} = type(`operator`(a.unsafeGet))
-    if x =? a:
-      `operator`(x).some
-    else:
-      T.none
-
-template liftBinary(_: type Option, operator: untyped) =
-
-  template `operator`*(a: ?typed, b: ?typed): ?typed =
-    type T = type(`operator`(a.unsafeGet, b.unsafeGet))
-    if x =? a and y =? b:
-      `operator`(x, y).some
-    else:
-      T.none
-
-  template `operator`*(a: ?typed, b: typed): ?typed =
-    type T = type(`operator`(a.unsafeGet, b))
-    if x =? a:
-      `operator`(x, b).some
-    else:
-      T.none
-
 Option.liftUnary(`-`)
 Option.liftUnary(`+`)
 Option.liftUnary(`@`)

questionable/results.nim

@@ -1,5 +1,6 @@
-import ./options
 import ./resultsbase
+import ./options
+import ./operators
 
 include ./errorban
 
@@ -8,18 +9,27 @@ export resultsbase
 template `?!`*(T: typed): type Result[T, ref CatchableError] =
   Result[T, ref CatchableError]
 
-template success*[T](value: T): ?!T =
+proc success*[T](value: T): ?!T =
   ok(?!T, value)
 
-template failure*(T: type, error: ref CatchableError): ?!T =
+proc failure*(T: type, error: ref CatchableError): ?!T =
   err(?!T, error)
 
-template `.?`*(value: ?!typed, field: untyped{nkIdent}): ?!untyped =
+template `->?`*(option: ?!typed, expression: untyped): untyped =
-  type T = type value.get.field
+  type T = type expression
-  if value.isOk:
+  if option.isErr:
-    ok(?!T, value.unsafeGet().field)
+    T.failure(option.error)
   else:
-    err(?!T, error(value))
+    expression.success
+
+template `->?`*(options: (?!typed, ?!typed), expression: untyped): untyped =
+  type T = type expression
+  if options[0].isErr:
+    T.failure(options[0].error)
+  elif options[1].isErr:
+    T.failure(options[1].error)
+  else:
+    expression.success
 
 template `|?`*[T](value: ?!T, fallback: T): T =
   value.valueOr(fallback)
@@ -34,33 +44,6 @@ proc toOption*[T,E](value: Result[T,E]): ?T =
   else:
     T.none
 
-template liftUnary(_: type Result, operator: untyped) =
-
-  template `operator`*(a: ?!typed): ?!typed =
-    type T {.used.} = type(`operator`(a.unsafeGet))
-    if x =? a:
-      `operator`(x).success
-    else:
-      T.failure(a.error)
-
-template liftBinary(_: type Result, operator: untyped) =
-
-  template `operator`*(a: ?!typed, b: ?!typed): ?!typed =
-    type T = type(`operator`(a.unsafeGet, b.unsafeGet))
-    if x =? a and y =? b:
-      `operator`(x, y).success
-    elif a.isErr:
-      T.failure(a.error)
-    else:
-      T.failure(b.error)
-
-  template `operator`*(a: ?!typed, b: typed): ?!typed =
-    type T = type(`operator`(a.unsafeGet, b))
-    if x =? a:
-      `operator`(x, b).success
-    else:
-      T.failure(a.error)
-
 Result.liftUnary(`-`)
 Result.liftUnary(`+`)
 Result.liftUnary(`@`)

testmodules/options/test.nim

@@ -1,5 +1,6 @@
 import std/unittest
 import std/sequtils
+import std/sugar
 import pkg/questionable
 
 suite "optionals":
@@ -16,6 +17,21 @@ suite "optionals":
     check b.?len == int.none
     check a.?len.?uint8 == 2'u8.some
     check b.?len.?uint8 == uint8.none
+    check a.?len() == 2.some
+    check b.?len() == int.none
+    check a.?distribute(2).?len() == 2.some
+    check b.?distribute(2).?len() == int.none
+
+  test ".? chain can be followed by . calls and operators":
+    let a = @[41, 42].some
+    check a.?len.get == 2
+    check a.?len.get.uint8.uint64 == 2'u64
+    check a.?len.get() == 2
+    check a.?len.get().uint8.uint64 == 2'u64
+    check a.?deduplicate()[0].?uint8.?uint64 == 41'u64.some
+    check a.?len + 1 == 3.some
+    check a.?deduplicate()[0] + 1 == 42.some
+    check a.?deduplicate.map(x => x) == @[41, 42].some
 
   test "[] can be used for indexing optionals":
     let a: ?seq[int] = @[1, 2, 3].some

testmodules/result/test.nim

@@ -1,6 +1,7 @@
 import std/unittest
 import std/sequtils
 import std/strutils
+import std/sugar
 import pkg/questionable
 import pkg/questionable/results
 
@@ -20,6 +21,21 @@ suite "result":
     check b.?len == int.failure error
     check a.?len.?uint8 == 2'u8.success
     check b.?len.?uint8 == uint8.failure error
+    check a.?len() == 2.success
+    check b.?len() == int.failure error
+    check a.?distribute(2).?len() == 2.success
+    check b.?distribute(2).?len() == int.failure error
+
+  test ".? chain can be followed by . calls and operators":
+    let a = @[41, 42].success
+    check (a.?len.get == 2)
+    check (a.?len.get.uint8.uint64 == 2'u64)
+    check (a.?len.get() == 2)
+    check (a.?len.get().uint8.uint64 == 2'u64)
+    check (a.?deduplicate()[0].?uint8.?uint64 == 41'u64.success)
+    check (a.?len + 1 == 3.success)
+    check (a.?deduplicate()[0] + 1 == 42.success)
+    check (a.?deduplicate.map(x => x) == @[41, 42].success)
 
   test "[] can be used for indexing optionals":
     let a: ?!seq[int] = @[1, 2, 3].success
@@ -115,23 +131,23 @@ suite "result":
 
     # chaining:
     let amount = works().?deduplicate.?len
-    check amount == 2.success
+    check (amount == 2.success)
 
     # fallback values:
     let value = fails() |? @[]
-    check value == newSeq[int](0)
+    check (value == newSeq[int](0))
 
     # lifted operators:
     let sum = works()[3] + 40
-    check sum == 42.success
+    check (sum == 42.success)
 
     # catch
     let x = parseInt("42").catch
-    check x == 42.success
+    check (x == 42.success)
     let y = parseInt("XX").catch
     check y.isErr
 
     # Conversion to Option
 
     let converted = works().toOption
-    check converted == @[1, 1, 2, 2, 2].some
+    check (converted == @[1, 1, 2, 2, 2].some)