Option existential quantifiers

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Next version
 
+### API changes
+
+- Add `Option.isNoneOr` and `Option.isSomeAnd` /~https://github.com/rescript-association/rescript-core/pull/124
+
 ## 0.4.0
 
 ### API changes

src/Core__Option.mjs

@@ -104,6 +104,22 @@ function compare(a, b, cmp) {
   }
 }
 
+function isSomeAnd(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 ,
@@ -117,5 +133,7 @@ export {
   isNone ,
   equal ,
   compare ,
+  isSomeAnd ,
+  isNoneOr ,
 }
 /* No side effect */

src/Core__Option.res

@@ -104,3 +104,15 @@ let compare = (a, b, cmp) =>
   | (Some(_), None) => Core__Ordering.greater
   | (None, None) => Core__Ordering.equal
   }
+
+let isSomeAnd = (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 @@ compare(None, None, clockCompare) // 0.
 ```
 */
 let compare: (option<'a>, option<'b>, ('a, 'b) => Core__Ordering.t) => Core__Ordering.t
+
+/**
+`isSomeAnd(option, predicate)` tests whether the option is `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. `isSomeAnd` is similar to `Array.some` and acts like the "there exists" quantifier in mathematics. It returns false for a `None` option.
+
+## Examples
+
+```rescript
+Option.isSomeAnd(None, i => i >= 0) // false
+Option.isSomeAnd(Some(3), i => i > 1) // true
+Option.isSomeAnd(Some(3), i => i < 0) // false
+```
+*/
+let isSomeAnd: (option<'a>, 'a => bool) => bool
+
+/**
+`isNoneOr(option, predicate)` tests whether the option is `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. `isNoneOr` is similar to `Array.every` and acts like the "for all" quantifier in mathematics. In particular it returns true when the option is `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",
+        12,
+        13,
+        47
+      ],
+      "isSomeAnd: if None, return false"
+    ], Core__Option.isSomeAnd(undefined, isPositive), eq, false);
+
+Test.run([
+      [
+        "OptionTests.res",
+        19,
+        13,
+        55
+      ],
+      "isSomeAnd: if Some and true, return true"
+    ], Core__Option.isSomeAnd(1, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        25,
+        13,
+        57
+      ],
+      "isSomeAnd: if Some and false, return false"
+    ], Core__Option.isSomeAnd(-1, isPositive), eq, false);
+
+Test.run([
+      [
+        "OptionTests.res",
+        31,
+        20,
+        52
+      ],
+      "isNoneOr: if None, return true"
+    ], Core__Option.isNoneOr(undefined, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        33,
+        13,
+        54
+      ],
+      "isNoneOr: if Some and true, return true"
+    ], Core__Option.isNoneOr(1, isPositive), eq, true);
+
+Test.run([
+      [
+        "OptionTests.res",
+        39,
+        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 +1,43 @@
+open RescriptCore
+
+let eq = (a, b) => a == b
+
+// ======================
+// isSomeAnd and isNoneOr
+// ======================
+
+let isPositive = i => i > 0
+
+Test.run(
+  __POS_OF__("isSomeAnd: if None, return false"),
+  None->Option.isSomeAnd(isPositive),
+  eq,
+  false,
+)
+
+Test.run(
+  __POS_OF__("isSomeAnd: if Some and true, return true"),
+  Some(1)->Option.isSomeAnd(isPositive),
+  eq,
+  true,
+)
+Test.run(
+  __POS_OF__("isSomeAnd: if Some and false, return false"),
+  Some(-1)->Option.isSomeAnd(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";
 import * as ResultTests from "./ResultTests.mjs";
 import * as TypedArrayTests from "./TypedArrayTests.mjs";
@@ -34,8 +35,6 @@ var forEachIfOkCallFunction = ResultTests.forEachIfOkCallFunction;
 
 var forEachIfErrorDoNotCallFunction = ResultTests.forEachIfErrorDoNotCallFunction;
 
-var eq = TypedArrayTests.eq;
-
 var num1 = TypedArrayTests.num1;
 
 var num2 = TypedArrayTests.num2;
@@ -50,6 +49,10 @@ var areSame = TypedArrayTests.areSame;
 
 var o = TypedArrayTests.o;
 
+var eq = OptionTests.eq;
+
+var isPositive = OptionTests.isPositive;
+
 export {
   bign ,
   TestError ,
@@ -64,13 +67,14 @@ export {
   $$catch ,
   forEachIfOkCallFunction ,
   forEachIfErrorDoNotCallFunction ,
-  eq ,
   num1 ,
   num2 ,
   num3 ,
   assertTrue ,
   assertWillThrow ,
   areSame ,
   o ,
+  eq ,
+  isPositive ,
 }
 /* IntTests Not a pure module */

test/TestSuite.res

@@ -5,3 +5,4 @@ include ArrayTests
 include IntTests
 include ResultTests
 include TypedArrayTests
+include OptionTests