Implement support for unqiue config instances.

This commit adds a new type, SpewState, which can be used to create
instances with unique configuration options.  The methods of SpewState are
equivalent to the top-level functions.  Full documentation and examples
are included.

1 files changed, 11 insertions, 5 deletions

diff --git a/spew/dump.go b/spew/dump.go
index 067f98e..361e90e 100644
--- a/spew/dump.go
+++ b/spew/dump.go
@@ -281,9 +281,9 @@ func (d *dumpState) dump(v reflect.Value) {
 	}
 }
 
-// Fdump formats and displays the passed arguments to io.Writer w.  It formats
-// exactly the same as Dump.

-func Fdump(w io.Writer, a ...interface{}) {
+// fdump is a helper function to consolidate the logic from the various public
+// methods which take varying writers and config states.
+func fdump(cs *ConfigState, w io.Writer, a ...interface{}) {
 	for _, arg := range a {
 		if arg == nil {
 			w.Write(interfaceBytes)
@@ -292,13 +292,19 @@ func Fdump(w io.Writer, a ...interface{}) {
 			continue
 		}
 
-		d := dumpState{w: w, cs: &Config}
+		d := dumpState{w: w, cs: cs}
 		d.pointers = make(map[uintptr]int)
 		d.dump(reflect.ValueOf(arg))
 		d.w.Write(newlineBytes)
 	}
 }
 
+// Fdump formats and displays the passed arguments to io.Writer w.  It formats
+// exactly the same as Dump.
+func Fdump(w io.Writer, a ...interface{}) {
+	fdump(&Config, w, a...)
+}
+
 /*
 Dump displays the passed parameters to standard out with newlines, customizable
 indentation, and additional debug information such as complete types and all
@@ -320,5 +326,5 @@ spew.Config.  See ConfigState for options documentation.
 See Fdump if you would prefer dump to an arbitrary io.Writer.
 */
 func Dump(a ...interface{}) {
-	Fdump(os.Stdout, a...)
+	fdump(&Config, os.Stdout, a...)
 }