Init

.gitignore

@@ -0,0 +1 @@
+*.exe

oi.nimble

@@ -0,0 +1,13 @@
+# Package
+
+version       = "0.1.0"
+author        = "luxick"
+description   = "Generic result type for operations that can fail."
+license       = "GPL-2.0"
+srcDir        = "src"
+
+
+
+# Dependencies
+
+requires "nim >= 1.2.4"

src/oi.nim

@@ -0,0 +1,17 @@
+type
+  Err = string
+  OI*[T] = object of RootObj
+    case isOk*: bool
+    of true:
+      val*: T
+    of false:
+      error*: string
+
+proc ok*[T](val: T): OI[T] =
+  OI[T](isOK: true, val: val)
+
+proc fail*(oi: OI, msg: string): OI =
+  OI(isOK: false, error: msg)
+
+proc fail*(msg: string): OI[auto] =
+  OI[auto](isOK: false, error: msg)

tests/config.nims

@@ -0,0 +1 @@
+switch("path", "$projectDir/../src")

tests/testResults.nim

@@ -0,0 +1,38 @@
+# To run these tests, simply execute `nimble test`.
+
+import unittest
+import oi
+
+test "Check OK":
+  let test = ok 1
+  check test.isOk == true
+
+test "Check fail":
+  let test = fail "no data here"
+  check test.isOk == false
+
+test "Check proc results":
+  proc createValue: OI[string] =
+    let myString = "This is test code!"
+    ok myString
+  let data = createValue()
+  check data.isOk
+  check data.val == "This is test code!"
+
+test "Check failing proc":
+  proc destinedToFail(): OI[int] =
+    result.fail "no data found"
+
+  let data = destinedToFail()
+  check data.isOk == false
+  check data.error == "no data found"
+
+test "Check changing result":
+  proc checker(): OI[int] =
+    result = ok 42
+    # something happend here
+    result = fail "data got corrupted"
+
+  let data = checker()
+  check data.isOk == false
+  check data.error == "data got corrupted"