Bump to 2.0.0.0, Append changelog, Update readme

ChangeLog.md

@@ -1,5 +1,38 @@
 # Revision history for butcher
 
+## 2.0.0.0  -- Sept 2020
+
+Large internal refactor including some breaking API changes.
+
+- Add the "Applicative" interface in addition to the existing "Monadic" one.
+  This is slightly less expressive but conceptually cleaner/safer (and its
+  implementation is nicer). For best readability you may need `ApplicativeDo`.
+- The applicative interface is *NOT* finished and the test-suite does not
+  cover it.
+- Add the `traverseBarbie` construct to elegantly define a parser for a
+  config data-structure.\
+  Introduces a dependency on the `barbies` library.
+- Refactor the module structure a bit, and change the API of the central
+  `runCmdParser` function. It now returns a `PartialParseInfo`. Essentially,
+  `runCmdParser` is a combination of the previous `runCmdParser` and the
+  previous `simpleCompletion`. This API design is a curious advantage to
+  laziness: Returning a complex struct is harmless as fields that the user
+  does not use won't be evaluated. The downside is that the core function now
+  looks like a complex beast, but the upside is that there is no need to
+  expose multiple functions that are supposed to be chained in a certain way
+  to get all functionality (if desired), and we still _can_ provide simpler
+  versions that are just projections on the `PartialParseInfo`.
+- Remove deprecated functions
+- `peekCmdDesc` is now guaranteed to yield the proper full `CmdDesc` value
+  for the current command or child-command.
+- Remove the `mainFromCmdParserWithHelpDesc` function, because it is redundant
+  given the new semantics of `peekCmdDesc`.
+- Stop support for an anti-feature: The implicit merging of multiple
+  sub-commands definitions with the same name.
+- Internal refactor: The monadic interface now uses two-phase setup: First step
+  is to create a full CommandDesc value, second is running the parser on input
+  while the CommandDesc is chained along
+
 ## 1.3.3.2  -- June 2020
 
 * Support ghc-8.10

README.md

@@ -9,19 +9,24 @@ The main differences are:
 
 * Provides a pure interface by default
 
-* Exposes an evil monadic interface, which allows for much nicer binding of
+* Exposes two interfaces: One based on `Applicative` and one based on `Monad`.
-  command part results to some variable name.
+  The monadic one is slightly more expressive, the applicative interface is
+  conceptually cleaner but currently is less tested.
 
-    In `optparse-applicative` you easily lose track of what field you are
+* The monadic interface must be used as if `ApplicativeDo` was enabled,
-    modifying after the 5th `<*>` (admittedly, i think -XRecordWildCards
+  but does not actually require `ApplicativeDo`. This is implemented via
-    improves on that issue already.)
+  some evil hackery, but nonetheless useful.
 
-    Evil, because you are not allowed to use the monad's full power in this
+* It is not necessary to define data-structure for diffenent child-commands.
-    case, i.e. there is a constraint that is not statically enforced.
+  In general this is geared towards keeping names and definitions/parsers
-    See below.
+  of flags/parameters/child-commands connected, while the default
+  `MyFlags <$> someParser <*> … <*> … <*> … <*> … <*> …` is harder to read
+  and prone to accidental swapping.
 
-* The monadic interface allows much clearer definitions of commandparses
+* Supports connecting to "barbies"
-  with (nested) subcommands. No pesky sum-types are necessary.
+  (see the [`barbies`](https://hackage.haskell.org/package/barbies) package).
+  This allows re-using data-structure definitions for the parser and config
+  values without losing track of field order.
 
 ## Examples
 
@@ -34,7 +39,9 @@ main = mainFromCmdParser $ addCmdImpl $ putStrLn "Hello, World!"
 But lets look at a more feature-complete example:
 
 ~~~~.hs
-main = mainFromCmdParserWithHelpDesc $ \helpDesc -> do
+main = mainFromCmdParser $ do
+
+  helpDesc <- peekCmdDesc
 
   addCmdSynopsis "a simple butcher example program"
   addCmdHelpStr "a very long help document"
@@ -44,14 +51,14 @@ main = mainFromCmdParserWithHelpDesc $ \helpDesc -> do
       (flagHelpStr "print nothing but the numeric version")
     addCmdHelpStr "prints the version of this program"
     addCmdImpl $ putStrLn $ if porcelain
-      then "0.0.0.999"
+      then "1.0"
-      else "example, version 0.0.0.999"
+      else "example, version 1.0"
 
   addCmd "help" $ addCmdImpl $ print $ ppHelpShallow helpDesc
 
   short <- addSimpleBoolFlag "" ["short"]
     (flagHelpStr "make the greeting short")
-  name <- addStringParam "NAME"
+  name <- addParamString "NAME"
     (paramHelpStr "your name, so you can be greeted properly")
 
   addCmdImpl $ do
@@ -62,9 +69,7 @@ main = mainFromCmdParserWithHelpDesc $ \helpDesc -> do
 
 Further:
 
-- [Full description of the above example, including sample behaviour](example1.md)
+- See the examples folder included in the package
-- [Example of a pure usage of a CmdParser](example2.md)
-- [Example of using a CmdParser on interactive input](example3.md)
 - The [brittany](https://github.com/lspitzner/brittany) formatting tool is a
   program that uses butcher for implementing its commandline interface. See
   its [main module source](https://github.com/lspitzner/brittany/blob/master/src-brittany/Main.hs)

butcher.cabal

@@ -1,6 +1,6 @@
 cabal-version:       2.2
 name:                butcher
-version:             1.3.3.2
+version:             2.0.0.0
 synopsis:            Chops a command or program invocation into digestable pieces.
 description:         See the <https://github.com/lspitzner/butcher/blob/master/README.md README> (it is properly formatted on github).
 license:             BSD-3-Clause