Experimental support for ignoring comments when parsing JSON file.

Currently, comment lines can only be specified by a single character.
Fixes #234

Author: jacobwilliams

files/inputs/comments.json

@@ -0,0 +1,57 @@
+!
+!  This is a JSON file with comments
+!
+!  The comments are lines beginning with the `!` character.
+!  Here is an example of multiple comment lines
+
+{
+! this is an object
+"version": {
+"major": 2,
+"minor": 2,
+"patch": 1,
+"string": "2.2.1",  ! this is a string
+"svn": 7191
+}
+!the next line is a comma
+,
+!the previous line was a comma
+"files": [
+    "..\\path\\to\\files\\file1.txt",
+    "..\\path\\to\\files\\file2.txt",
+    "..\\path\\to\\files\\file3.txt",
+    "test \u2FA4 \uABCD \uABCD\uABCDtest",! this is an array element
+                                          ! another comment line.
+    "   test  \\u \" blah\\\" test test",
+    "..\\path\\to\\files\\",
+    " this string has ! comment characters !"
+  ],
+"empty_array": [
+    !an empty array
+  ],
+"empty_object": {
+},
+"empty_string": "",
+"data": [
+    {
+    "number": 1,
+    "tf1": true,
+    "tf2": false,
+    "empty": null,
+    "name": "Horatio",
+    "array": [
+        "1",
+        "2",
+        "3"
+      ]
+    },
+    ! blah blah
+    {
+    "number": 2,
+    "integer": 33,
+    "real": 0.2333000000000000E+003 ! how about a comment after a real
+    ,
+    "name": "Nelson"
+    }
+  ]
+} ! and we're done

src/json_file_module.F90

@@ -273,7 +273,8 @@ subroutine initialize_json_core_in_file(me,verbose,compact_reals,&
                                             trailing_spaces_significant,&
                                             case_sensitive_keys,&
                                             no_whitespace,&
-                                            unescape_strings)
+                                            unescape_strings,&
+                                            comment_char)
 
     implicit none
 
@@ -298,14 +299,19 @@ subroutine initialize_json_core_in_file(me,verbose,compact_reals,&
                                                         !! string is returned from [[json_get_string]]
                                                         !! and similar routines. If true [default],
                                                         !! then the string is returned unescaped.
+    character(kind=CK,len=1),intent(in),optional :: comment_char  !! If present, this character is used
+                                                                  !! to denote comments in the JSON file,
+                                                                  !! which will be ignored if present.
+                                                                  !! Example: `!` or `#`.
 
     call me%core%initialize(verbose,compact_reals,&
                             print_signs,real_format,spaces_per_tab,&
                             strict_type_checking,&
                             trailing_spaces_significant,&
                             case_sensitive_keys,&
                             no_whitespace,&
-                            unescape_strings)
+                            unescape_strings,&
+                            comment_char)
 
     end subroutine initialize_json_core_in_file
 !*****************************************************************************************
@@ -365,7 +371,8 @@ function initialize_json_file(p,verbose,compact_reals,&
                                   trailing_spaces_significant,&
                                   case_sensitive_keys,&
                                   no_whitespace,&
-                                  unescape_strings) result(file_object)
+                                  unescape_strings,&
+                                  comment_char) result(file_object)
 
     implicit none
 
@@ -392,14 +399,19 @@ function initialize_json_file(p,verbose,compact_reals,&
                                                         !! string is returned from [[json_get_string]]
                                                         !! and similar routines. If true [default],
                                                         !! then the string is returned unescaped.
+    character(kind=CK,len=1),intent(in),optional :: comment_char  !! If present, this character is used
+                                                                  !! to denote comments in the JSON file,
+                                                                  !! which will be ignored if present.
+                                                                  !! Example: `!` or `#`.
 
     call file_object%initialize(verbose,compact_reals,&
                                 print_signs,real_format,spaces_per_tab,&
                                 strict_type_checking,&
                                 trailing_spaces_significant,&
                                 case_sensitive_keys,&
                                 no_whitespace,&
-                                unescape_strings)
+                                unescape_strings,&
+                                comment_char)
 
     if (present(p)) file_object%p => p