Fragments: additional testing and documentation enhancements

Add test for original syntax when using a single fragment key containing
the list of dependent fragments. I couldn't find a test for this.

Spaces in the fragment list don't seem to work - document it.

CHANGES.current

@@ -7,6 +7,15 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.1.0 (in progress)
 ===========================
 
+2022-02-07: sethrj
+            #2196 Add alternative syntax for specifying fragments in typemaps.
+
+            New syntax:
+              %typemap("in", fragment="frag1", fragment="frag2", fragment="frag3") {...}
+            which is equivalent to:
+              %typemap(in, fragment="frag1,frag2,frag3") {...}
+
+
 2022-02-07: olly
 	    #1806 Remove support for the "command" encoder, which was mostly
 	    intended for use in `%rename` - most uses can be achieved using

Doc/Manual/Typemaps.html

@@ -3835,7 +3835,7 @@ To eliminate this, define a fragment that includes the common marshalling code:
 
 <p>
 When the "in" or "varin" typemaps for MyClass are required, the
-contents of the fragment called "AsMyClass" is added to the "header" section within the generated code, and then the
+contents of the fragment called "AsMyClass" are added to the "header" section within the generated code, and then the
 typemap code is emitted. Hence, the method <tt>AsMyClass</tt> will be
 generated into the wrapper code before any typemap code that calls it.
 </p>
@@ -3983,29 +3983,34 @@ inclusion of the other fragments.
 
 <li>
 <p>
-A typemap can also use more than one fragment with the same syntax:
+A typemap can also use more than one fragment:
 </p>
 <div class="code">
 <pre>
-%typemap("in", "header", fragment="frag1", fragment="frag2", fragment="frag3") "";
-</pre>
-</div>
-<p>
-<em>New in SWIG 4.1.</em>
-</p>
-
-<p>An older syntax allows multiple fragments to be specified in a comma
-separated list inside a single keyword argument. Consider:
-</p>
-
-<div class="code">
-<pre>
-%typemap(in, fragment="frag1, frag2, frag3") {...}
+%typemap("in", fragment="frag1", fragment="frag2", fragment="frag3") {...}
 </pre>
 </div>
 
 <p>
-which is equivalent to:
+<b>Compatibility note: </b> The ability to use multiple
+<tt>fragment</tt> keys as shown above was introduced in SWIG-4.1.0.
+</p>
+
+<p>
+Multiple fragments can alternatively be specified as a comma
+separated list value in a single <tt>fragment</tt> key.
+Note that no whitespace is allowed within this comma separated list.
+The following is the equivalent to the above:
+</p>
+
+<div class="code">
+<pre>
+%typemap(in, fragment="frag1,frag2,frag3") {...}
+</pre>
+</div>
+
+<p>
+which in turn is functionally equivalent to:
 </p>
 
 <div class="code">

Examples/test-suite/fragments.i

@@ -35,15 +35,35 @@ int foo(int hola)
 
 %}
 
+/* Instantiate multiple fragments at once using fragments in comma separated list */
+typedef int comma_frag3;
+
+%fragment("comma_frag1","header", noblock=1) {
+typedef int comma_frag1;
+}
+
+%fragment("comma_frag2","header", noblock=1, noblock=1) {
+typedef comma_frag1 comma_frag2;
+}
+
+%fragment("comma_frag3","header",
+          fragment="comma_frag1,comma_frag2")
+%{typedef comma_frag2 comma_frag3;%}
+
+%fragment("comma_frag3");
+%inline %{
+comma_frag3 my_comma_frag_int = 0;
+%}
+
+
 /* Instantiate multiple fragments at once using multiple keywords */
-typedef int int_infrag3;
 typedef int explicit_frag3;
 
 %fragment("explicit_frag1","header", noblock=1) {
 typedef int explicit_frag1;
 }
 
-%fragment("explicit_frag2","header", noblock=1, noblock=1) {
+%fragment("explicit_frag2","header", noblock=1) {
 typedef explicit_frag1 explicit_frag2;
 }
 
@@ -71,6 +91,7 @@ typedef int_infrag1 int_infrag2;
 typedef int int_infrag1;
 %}
 %fragment("infrag2","runtime") %{
+__second_infrag2_fragment_is_ignored_this_will_not_compile_if_emitted_
 typedef int_infrag1 int_infrag2;
 %}