%  Copyright (C) 2002-2005 David Roundy
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\begin{code}
{-# OPTIONS_GHC -cpp -fno-warn-orphans -fglasgow-exts #-}
{-# LANGUAGE CPP #-}

module Darcs.Patch.Show ( showPatch_, showNamedPrefix )
             where

import Prelude hiding ( pi )

import Printer ( Doc, renderString, vcat,
                 text, blueText,
                 ($$), (<+>) )
import Darcs.Patch.Core ( Patch(..) )
import Darcs.Patch.Prim ( showPrim, FileNameFormat(..) )
import Darcs.Patch.Info ( PatchInfo, showPatchInfo )
import Darcs.Witnesses.Ordered ( FL(NilFL), mapFL )
#include "gadts.h"
\end{code}

\section{Patch string formatting}

Of course, in order to store our patches in a file, we'll have to save them
as some sort of strings.  The convention is that each patch string will end
with a newline, but on parsing we skip any amount of whitespace between
patches.
\begin{code}
instance Show (Patch C(x y))  where
    show p = renderString (showPatch_ p) ++ "\n"

showPatch_ :: Patch C(a b) -> Doc
showPatch_ (PP p) = showPrim OldFormat p
showPatch_ (ComP NilFL) = blueText "{" $$ blueText "}"
showPatch_ (ComP ps)  = blueText "{"
                        $$ vcat (mapFL showPatch_ ps)
                        $$ blueText "}"
showPatch_ (Merger _ _ p1 p2) = showMerger "merger" p1 p2
showPatch_ (Regrem _ _ p1 p2) = showMerger "regrem" p1 p2
\end{code}

\paragraph{Merger patches}
Merge two patches.  The MERGERVERSION is included to allow some degree of
backwards compatibility if the merger algorithm needs to be changed.
\begin{verbatim}
merger MERGERVERSION
<first patch>
<second patch>
\end{verbatim}
\begin{code}
showMerger :: String -> Patch C(a b) -> Patch C(d e) -> Doc
showMerger merger_name p1 p2 =
    blueText merger_name <+> text "0.0" <+> blueText "("
                           $$ showPatch_ p1
                           $$ showPatch_ p2
                           $$ blueText ")"
\end{code}

\paragraph{Named patches}

Named patches are displayed as a ``patch id'' which is in square brackets,
followed by a patch.  Optionally, after the patch id (but before the patch
itself) can come a list of dependencies surrounded by angle brackets.  Each
dependency consists of a patch id.

\begin{code}
showNamedPrefix :: PatchInfo -> [PatchInfo] -> Doc
showNamedPrefix n d = showPatchInfo n
                   $$ blueText "<"
                   $$ vcat (map showPatchInfo d)
                   $$ blueText ">"

\end{code}