Add backwards compatiblity for isFunction

source/poodinis/autowire.d

@@ -21,6 +21,7 @@ import poodinis.container;
 import poodinis.registration;
 import poodinis.factory;
 import poodinis.valueinjection;
+import poodinis.polyfill;
 
 import std.exception;
 import std.stdio;

source/poodinis/container.d

@@ -18,6 +18,7 @@ import poodinis.autowire;
 import poodinis.context;
 import poodinis.factory;
 import poodinis.valueinjection;
+import poodinis.polyfill;
 
 import std.string;
 import std.algorithm;

source/poodinis/polyfill.d

@@ -4,20 +4,29 @@
  *
  * Should not implement functionalitiy which is gone from the latest Phobos.
  *
- * Implementations copied/re-implemented from std.exception
+ * Implementations copied/re-implemented from std.exception and std.traits;
  *
  * The baseline compatibility is D/Phobos 2.068.2
  *
  * Authors: $(HTTP erdani.org, Andrei Alexandrescu),
  *            Jonathan M Davis,
+ *            $(HTTP digitalmars.com, Walter Bright),
+ *            Tomasz Stachowiak ($(D isExpressions)),
+ *            $(HTTP erdani.org, Andrei Alexandrescu),
+ *            Shin Fujishiro,
+ *            $(HTTP octarineparrot.com, Robert Clipsham),
+ *            $(HTTP klickverbot.at, David Nadlinger),
+ *            Kenji Hara,
+ *            Shoichi Kato,
  *            Mike Bierlee (m.bierlee@lostmoment.com)
- * Copyright: Copyright Andrei Alexandrescu 2008-, Jonathan M Davis 2011-., 2014-2016 Mike Bierlee
+ * Copyright: Copyright Digital Mars 2005 - 2009., Copyright Andrei Alexandrescu 2008-, Jonathan M Davis 2011-., 2014-2016 Mike Bierlee
  * License:  $(HTTP boost.org/LICENSE_1_0.txt, Boost License 1.0)
  */
 
 module poodinis.polyfill;
 
 import std.exception;
+import std.traits;
 
 static if (!__traits(compiles, basicExceptionCtors)) {
 	mixin template basicExceptionCtors()
@@ -33,3 +42,22 @@ static if (!__traits(compiles, basicExceptionCtors)) {
 		}
 	}
 }
+
+static if (!__traits(compiles, isFunction)) {
+	template isFunction(X...) if (X.length == 1)
+	{
+		static if (is(typeof(&X[0]) U : U*) && is(U == function) ||
+					is(typeof(&X[0]) U == delegate))
+		{
+			// x is a (nested) function symbol.
+			enum isFunction = true;
+		}
+		else static if (is(X[0] T))
+		{
+			// x is a type.  Take the type of it and examine.
+			enum isFunction = is(T == function);
+		}
+		else
+			enum isFunction = false;
+	}
+}