git config added

scribblings/git.scrbl

@@ -19,7 +19,8 @@ read credentials or other answers from the terminal.
 Runs a registered Git @racket[command]. The arguments are passed to the command.
 Registered command symbols are @racket['status], @racket['add],
 @racket['commit], @racket['push], @racket['pull], @racket['fetch],
-@racket['branch], @racket['switch], @racket['clone], @racket['tag],
+@racket['config], @racket['branch], @racket['switch], @racket['clone],
+@racket['tag],
 @racket['log], @racket['rev-list], @racket['diff],
 @racket['show], @racket['grep], @racket['help], @racket['version], and
 @racket['new-version].
@@ -88,6 +89,46 @@ For example:
 ]
 }
 
+@defproc[(git-config [argument any/c] ...) any/c]{
+Provides a Racket-oriented interface to @tt{git config}. The same interface is
+available through @racket[git] with command @racket['config].
+
+@racketblock[
+(git 'config 'get '--all)
+]
+
+returns all visible configuration entries as key/value items:
+
+@racketblock[
+'(("user.name" "Hans Dijkema")
+  ("user.email" "hans@example.invalid")
+  ("credential.helper" "manager"))
+]
+
+@racketblock[
+(git 'config 'get "credential.helper")
+]
+
+returns one value as a string, or @racket[#f] when the key is absent.
+
+@racketblock[
+(git 'config 'get '--all "credential.helper")
+]
+
+returns all values for one key as a list. An absent key produces the empty
+list.
+
+Configuration values can be written with @racket['set!]:
+
+@racketblock[
+(git 'config 'set! "user.email" "hans@example.invalid")
+(git 'config 'set! '--global "user.email" "hans@example.invalid")
+]
+
+The optional write scope can be @tt{--global}, @tt{--local}, or @tt{--system}.
+A successful write returns @racket[#t].
+}
+
 @defproc[(git-branch [argument any/c] ...) boolean?]{
 Runs @tt{git branch} with the supplied arguments. This can be used to list,
 create, rename, or delete branches according to the options supported by the