Option.exists and Option.isNoneOr

Author: jmagaram

src/Core__Option.mjs

@@ -106,6 +106,22 @@ function cmp(a, b, f) {
   }
 }
 
+function exists(o, p) {
+  if (o !== undefined) {
+    return Curry._1(p, Caml_option.valFromOption(o));
+  } else {
+    return false;
+  }
+}
+
+function isNoneOr(o, p) {
+  if (o !== undefined) {
+    return Curry._1(p, Caml_option.valFromOption(o));
+  } else {
+    return true;
+  }
+}
+
 export {
   filter ,
   forEach ,
@@ -119,5 +135,7 @@ export {
   isNone ,
   eq ,
   cmp ,
+  exists ,
+  isNoneOr ,
 }
 /* No side effect */

src/Core__Option.res

@@ -111,3 +111,15 @@ let cmpU = (a, b, f) =>
   }
 
 let cmp = (a, b, f) => cmpU(a, b, (. x, y) => f(x, y))
+
+let exists = (o, p) =>
+  switch o {
+  | None => false
+  | Some(v) => p(v)
+  }
+
+let isNoneOr = (o, p) =>
+  switch o {
+  | None => true
+  | Some(v) => p(v)
+  }

src/Core__Option.resi

@@ -248,3 +248,33 @@ cmp(None, None, clockCompare) // 0
 ```
 */
 let cmp: (option<'a>, option<'b>, ('a, 'b) => int) => int
+
+/**
+`exists(option, predicate)` tests whether the option is both `Some` and the predicate applied to its value is true.
+
+An option can be thought of as an array with 0 or 1 items in it. This function is similar to `Array.some` and acts like the "there exists" quantifier in mathematics. In particular it returns false for an "empty" option with a value of `None`.
+
+## Examples
+
+```rescript
+Option.exists(None, i => i >= 0) // false
+Option.exists(Some(3), i => i > 1) // true
+Option.exists(Some(3), i => i < 0) // false
+```
+*/
+let exists: (option<'a>, 'a => bool) => bool
+
+/**
+`isNoneOr(option, predicate)` tests whether the option is either `None` or the predicate applied to its value is true.
+
+An option can be thought of as an array with 0 or 1 items in it. This function is similar to `Array.every` and acts like the "for all" quantifier in mathematics. In particular it returns true for an "empty" option with a value of `None`
+
+## Examples
+
+```rescript
+Option.isNoneOr(None, i => i >= 0) // true
+Option.isNoneOr(Some(3), i => i > 1) // true
+Option.isNoneOr(Some(3), i => i < 0) // false
+```
+*/
+let isNoneOr: (option<'a>, 'a => bool) => bool

test/OptionTests.mjs

@@ -0,0 +1,77 @@
+// Generated by ReScript, PLEASE EDIT WITH CARE
+
+import * as Test from "./Test.mjs";
+import * as Caml_obj from "rescript/lib/es6/caml_obj.js";
+import * as Core__Option from "../src/Core__Option.mjs";
+
+var eq = Caml_obj.equal;
+
+function isPositive(i) {
+  return i > 0;
+}
+
+Test.run([
+      [
+        "OptionTests.res",
+        11,
+        20,
+        51
+      ],
+      "exists: if None, return false"
+    ], Core__Option.exists(undefined, isPositive), eq, false);
+
+Test.run([
+      [
+        "OptionTests.res",
+        13,
+        13,
+        52
+      ],
+      "exists: if Some and true, return true"
+    ], Core__Option.exists(1, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        19,
+        13,
+        54
+      ],
+      "exists: if Some and false, return false"
+    ], Core__Option.exists(-1, isPositive), eq, false);
+
+Test.run([
+      [
+        "OptionTests.res",
+        25,
+        20,
+        52
+      ],
+      "isNoneOr: if None, return true"
+    ], Core__Option.isNoneOr(undefined, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        27,
+        13,
+        54
+      ],
+      "isNoneOr: if Some and true, return true"
+    ], Core__Option.isNoneOr(1, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        33,
+        13,
+        56
+      ],
+      "isNoneOr: if Some and false, return false"
+    ], Core__Option.isNoneOr(-1, isPositive), eq, false);
+
+export {
+  eq ,
+  isPositive ,
+}
+/*  Not a pure module */

test/OptionTests.res

@@ -0,0 +1,37 @@
+open RescriptCore
+
+let eq = (a, b) => a == b
+
+// ===================
+// exists and isNoneOr
+// ===================
+
+let isPositive = i => i > 0
+
+Test.run(__POS_OF__("exists: if None, return false"), None->Option.exists(isPositive), eq, false)
+Test.run(
+  __POS_OF__("exists: if Some and true, return true"),
+  Some(1)->Option.exists(isPositive),
+  eq,
+  true,
+)
+Test.run(
+  __POS_OF__("exists: if Some and false, return false"),
+  Some(-1)->Option.exists(isPositive),
+  eq,
+  false,
+)
+
+Test.run(__POS_OF__("isNoneOr: if None, return true"), None->Option.isNoneOr(isPositive), eq, true)
+Test.run(
+  __POS_OF__("isNoneOr: if Some and true, return true"),
+  Some(1)->Option.isNoneOr(isPositive),
+  eq,
+  true,
+)
+Test.run(
+  __POS_OF__("isNoneOr: if Some and false, return false"),
+  Some(-1)->Option.isNoneOr(isPositive),
+  eq,
+  false,
+)

test/TestSuite.mjs

@@ -4,6 +4,7 @@ import * as IntTests from "./IntTests.mjs";
 import * as TestTests from "./TestTests.mjs";
 import * as ArrayTests from "./ArrayTests.mjs";
 import * as ErrorTests from "./ErrorTests.mjs";
+import * as OptionTests from "./OptionTests.mjs";
 import * as PromiseTest from "./PromiseTest.mjs";
 
 var bign = TestTests.bign;
@@ -26,10 +27,12 @@ var Concurrently = PromiseTest.Concurrently;
 
 var panicTest = ErrorTests.panicTest;
 
-var eq = IntTests.eq;
-
 var $$catch = IntTests.$$catch;
 
+var eq = OptionTests.eq;
+
+var isPositive = OptionTests.isPositive;
+
 export {
   bign ,
   TestError ,
@@ -41,7 +44,8 @@ export {
   Catching ,
   Concurrently ,
   panicTest ,
-  eq ,
   $$catch ,
+  eq ,
+  isPositive ,
 }
 /* IntTests Not a pure module */

test/TestSuite.res

@@ -3,3 +3,4 @@ include PromiseTest
 include ErrorTests
 include ArrayTests
 include IntTests
+include OptionTests