ENH: allow "<case>", "<system>" ... in the string expansions (issue #792)

- the expansions were previously required as slash to follow, but
  now either are possible.

    "<case>", "<case>/" both yield the same as "$FOAM_CASE" and
    will not have a trailing slash in the result. The expansion of
    "$FOAM_CASE/" will however have a trailing slash.

- adjust additional files using these expansions

applications/test/string/Test-string.C

@@ -72,26 +72,28 @@ int main(int argc, char *argv[])
             const auto& cstr
           :
             {
-                "~OpenFOAM/controlDict",
-                "<etc>/controlDict",
+                "~OpenFOAM/controlDict",    "<etc>/controlDict",
+                "$FOAM_CASE/xyz",           "<case>/xyz",
+                "$FOAM_CASE/constant/xyz",  "<constant>/xyz",
+                "$FOAM_CASE/system/xyz",    "<system>/xyz",
 
-                "$FOAM_CASE/test",
-                "<case>/test",
+                // corner cases
+                "~OpenFOAM",                "<etc>",
+                "~OpenFOAM/",               "<etc>/",
+                "$FOAM_CASE",               "<case>",
+                "$FOAM_CASE/constant",      "<constant>",
+                "$FOAM_CASE/system",        "<system>",
 
-                "$FOAM_CASE/constant/test",
-                "<case>/constant/test",
-                "<constant>/test",
-
-                "$FOAM_CASE/system/test",
-                "<case>/system/test",
-                "<system>/test",
+                "$FOAM_CASE/",              "<case>/",
+                "$FOAM_CASE/constant/",     "<constant>/",
+                "$FOAM_CASE/system/",       "<system>/",
             }
         )
         {
             string input(cstr);
             string output(stringOps::expand(input));
 
-            Info<<"input:   " << input << nl
+            Info<< "input:  " << input  << nl
                 << "expand: " << output << nl << nl;
         }
     }

applications/utilities/mesh/generation/extrude/extrudeMesh/extrudeMeshDict

@@ -112,10 +112,10 @@ sigmaRadialCoeffs
 offsetSurfaceCoeffs
 {
     // Surface that mesh has been meshed to
-    baseSurface "$FOAM_CASE/constant/triSurface/DTC-scaled-inflated.obj";
+    baseSurface     "<constant>/triSurface/DTC-scaled-inflated.obj";
 
     // Surface to fill in to
-    offsetSurface "$FOAM_CASE/constant/triSurface/DTC-scaled.obj";
+    offsetSurface   "<constant>/triSurface/DTC-scaled.obj";
 }
 
 

applications/utilities/preProcessing/createZeroDirectory/createZeroDirectory.C

@@ -150,7 +150,7 @@ void createFieldFiles
         field.add
         (
             "#include",
-            "${FOAM_CASE}/system" + regionPath + "caseProperties"
+            "$FOAM_CASE/system" + regionPath + "caseProperties"
         );
 
         field.add("dimensions", fieldDimensions[i]);