parse-option-value: call as(param, type) in default method

command-line-parser.dylan

@@ -480,11 +480,16 @@ end method;
 define open generic parse-option-value
     (parameter :: <string>, type :: <type>) => (value :: <object>);
 
-// Default method just returns the value.
 define method parse-option-value
-    (param :: <string>, type :: <type>) => (value :: <string>)
-  param
-end;
+    (param :: <string>, type :: <type>) => (value :: <object>)
+  block ()
+    // If type happens to have an AS method (for example like <file-locator> does) then
+    // we will automatically support that type.
+    as(type, param)
+  exception (<error>)
+    param
+  end
+end method;
 
 // This is essentially for "float or int", which could be <real>, but
 // <number> is also a natural choice.

tests/command-line-parser-test-suite-library.dylan

@@ -13,6 +13,7 @@ define module command-line-parser-test-suite
   use command-line-parser;
   use common-dylan, exclude: { format-to-string };
   use format;
+  use locators;
   use option-parser-protocol,
     import: {
       option-help,

tests/command-line-parser-test-suite.dylan

@@ -187,6 +187,10 @@ define test test-option-type ()
                                   help: "x",
                                   names: #("repeated-integer"),
                                   type: <integer>));
+          add-option(parser, make(<parameter-option>,
+                                  help: "x",
+                                  names: #("file-locator"),
+                                  type: <file-locator>));
           parser
         end method make-parser;
   let items = list(list("integer", "123", 123, <integer>),
@@ -198,7 +202,9 @@ define test test-option-type ()
                    list("symbol", "foo", #"foo", <symbol>),
                    list("number", "123", 123, <integer>),
                    list("real", "123", 123, <integer>),
-                   list("string", "bar", "bar", <string>));
+                   list("string", "bar", "bar", <string>),
+                   list("file-locator", "/tmp/x", as(<file-locator>, "/tmp/x"),
+                        <file-locator>));
   for (item in items)
     let (name, param, expected-value, expected-type) = apply(values, item);
     let parser = make-parser();