Adding Call, ToOperation

Canon/src/Utils/TypeConversion.qs

@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-
 namespace Microsoft.Quantum.Canon
 {
 
@@ -178,6 +177,58 @@ namespace Microsoft.Quantum.Canon
         return arr;
     }
 
+    /// # Summary
+    /// Calls a function with a given input.
+    ///
+    /// # Description
+    /// Given a function and an input to that function, calls the function
+    /// and returns its output.
+    ///
+    /// # Input
+    /// ## fn
+    /// A function to be called.
+    /// ## input
+    /// The input to be passed to the function.
+    ///
+    /// # Output
+    /// The result of calling `fn`.
+    ///
+    /// # Remarks
+    /// This operation is mainly useful for forcing a function to be called
+    /// at a specific place within an operation, or for calling a function
+    /// where an operation is expected.
+    operation Call<'Input, 'Output>(fn : ('Input -> 'Output), input : 'Input) : 'Output {
+        return fn(input);
+    }
+
+    /// # Summary
+    /// Converts functions to operations.
+    ///
+    /// # Description
+    /// Given a function, returns an operation which calls that function,
+    /// and which does nothing else.
+    ///
+    /// # Input
+    /// ## fn
+    /// A function to be converted to an operation.
+    ///
+    /// # Output
+    /// An operation `op` such that `op(input)` is identical to `fn(input)`
+    /// for all `input`.
+    ///
+    /// # Type Parameters
+    /// ## 'Input
+    /// Input type of the function to be converted.
+    /// ## 'Output
+    /// Output type of the function to be converted.
+    ///
+    /// # Remarks
+    /// This is mainly useful for passing functions to functions or operations
+    /// which expect an operation as input.
+    function ToOperation<'Input, 'Output>(fn : ('Input -> 'Output)) : ('Input => 'Output) {
+        return Call(fn, _);
+    }
+
 }
 
 

Canon/tests/TypeConversionTests.qs

@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+namespace Microsoft.Quantum.Tests {
+    open Microsoft.Quantum.Primitive;
+    open Microsoft.Quantum.Canon;
+
+    function Square(x : Int) : Int {
+        return x * x;
+    }
+
+    operation ApplyOp<'T, 'U>(op : ('T => 'U), input : 'T) : 'U {
+        return op(input);
+    }
+
+    operation CallTest() : Unit {
+        AssertIntEqual(Call(Square, 4), 16, "Call failed with Square.");
+    }
+
+    operation ToOperationTest : Unit {
+        let op = ToOperation(Square);
+        AssertIntEqual(ApplyOp(op, 3), 9);
+    }
+
+}
+
+