packages feed

BlogLiterately 0.2 → 0.3

raw patch · 4 files changed

+641/−640 lines, 4 filesdep ~HaXmldep ~basedep ~haxr

Dependency ranges changed: HaXml, base, haxr, hscolour, pandoc

Files

BlogLiterately.cabal view
@@ -1,158 +1,158 @@-Name:           BlogLiterately-Version:        0.2-Synopsis:	A tool for posting Haskelly articles to blogs--Description:     BlogLiterately is a tool for uploading web log posts to web log servers-                 that support the MetaWeblog API (such as WordPress-based blogs and many-                 others).  Blog posts to be published via BlogLiterately are written in-                 markdown [1] format, with extensions supported by pandoc [2].  Posts may be-                 actual 'bird-style' literate Haskell files, with commentary in markdown.-                 Code segments (including actual source lines from literate haskell files,-                 as well as markdown code blocks) may be syntax-highlighted in the resulting-                 HTML that is posted to the blog.  There are two types (two different-                 libraries used) of formatting available for formatting code segments.-                 .-                   * Hscolour (for formatting Haskell code segments)-                 .-                   * highlighting-kate (for formatting Haskell and non-haskell segments)-                 .-                 The Markdown webpage has information about markdown formatting options,-                 and the Pandoc website has information about the extensions supported.-                 BlogLiterately extends the notation a bit further, for specifying code-                 segments.  In basic markdown, A code segment is set off from normal-                 text via indentation, e.g.:-                 .-                 >   -- This is a code segment but the tool doesn't know what kind!-                 >   foo :: String -> String-                 .-                 Pandoc offers another way to specify a code segment (replace the-                 square braces with curly braces, haddock/hackage mangles them):-                 .-                 > ~~~~ [ .haskell ] -                 > -- This is a code segment, and the tool knows it's Haskell!-                 > foo :: String -> String -                 > ~~~~-                 .-                 BlogLiterately lets you specify a Haskell segment this way (this is-                 just a normal markdown indented code block with an extra tag at-                 the top.  In either the above way of specifying the type of code-                 in the block, you may specify other kinds of code besides haskell,-                 e.g. cpp, bash, java, ml, eiffel, etc.):-                 .-                 >     [haskell]-                 >     -- This is a code segment, and the tool knows it's Haskell!-                 >     foo :: String -> String-                 .-                 Once you have written your markdown file, you can run the tool, specifying how-                 you want it highlighted.  You can specify different highlighting modes for-                 the haskell segments and the other code segments.  If using hscolour, you-                 can specify that the highlighting be done 'inline' via CSS 'style'-                 attributes.  You can use the default styling (which is similar to source-                 code in documentation on hackage) or you can specify a configuration file-                 which looks something like this:-                 .-                 >     [("hs-keyword","color: blue; font-weight: bold;")-                 >     , ("hs-keyglyph","color: red;")-                 >     , ("hs-layout","color: red;")-                 >     , ("hs-comment","color: green;")-                 >     , ("hs-conid", "")-                 >     , ("hs-varid", "")-                 >     , ("hs-conop", "")-                 >     , ("hs-varop", "")-                 >     , ("hs-str", "color: teal;")-                 >     , ("hs-chr", "color: teal;")-                 >     , ("hs-number", "")-                 >     , ("hs-cpp", "")-                 >     , ("hs-selection", "")-                 >     , ("hs-variantselection", "")-                 >     , ("hs-definition", "")]-                 .-                 It has to be (readable as) a Haskell value of type [(String,String)],-                 and it will only have an effect if you use the above class names (e.g.-                 'hs-keyword' to specify a style for Haskell keywords).-                 .-                 With highlighting-kate (always) and with hscolour-                 (optionally), the style for syntax segments is specified using 'class'-                 attributes, so the stylesheet must be provided separately.  Sample -                 stylesheets are provided in the package archive file.-                 .-                 To use the highlighting-kate, you must (re)install Pandoc with highlighting-                 enabled, like so:-                 .-                 > cabal install -fhighlighting pandoc-                 .-                 or-                 .-                 > cabal install --reinstall -fhighlighting pandoc-                 .-                 (If you have already installed BlogLiterately, you must reinstall that-                 as well).-                 .-                 The options for BlogLiterately are, I hope, self-explanatory (given the -                 above background!).  Note that if Pandoc isn't installed with highlighting-                 enabled, there will be fewer options (no -kate options):-                 .-                 > BlogLierately v0.2, (C) Robert Greayer 2009-                 > This program comes with ABSOLUTELY NO WARRANTY-                 > -                 > -                 > BlogLiterately [FLAG] URL USER PASSWORD TITLE FILE-                 > -                 >   -? --help[=FORMAT]    Show usage information (optional format)-                 >   -V --version          Show version information-                 >   -v --verbose          Higher verbosity-                 >   -q --quiet            Lower verbosity-                 >   -t --test             do a test-run: html goes to stdout, is not posted-                 >   -s --style=FILE       Style Specification (for --hscolour-icss)-                 >      --hscolour-icss    hilight haskell: hscolour, inline style (default)-                 >      --hscolour-css     hilight haskell: hscolour, separate stylesheet-                 >      --hs-nohilight     no haskell hilighting-                 >      --hs-kate          hilight haskell with highlighting-kate-                 >      --other-code-kate  hilight other code with highlighting-kate-                 >      --publish          Publish post (otherwise it's uploaded as a draft)-                 >      --category=VALUE   post category (can specify more than one)-                 >   -b --blogid=VALUE     Blog specific identifier (default=default)-                 >      --postid=VALUE     Post to replace (if any)-                 .-                 .-                 To post to a WordPress blog, the command is:-                 .-                 >     BlogLiterately http://blogurl.example.com/xmlrpc.php \-                 >         myname mypasswd "Sample" Sample.lhs-                 .-                 (which creates a new post).  If, for example, the post id of that post-                 (which BlogLiterately prints when it uploads a new post) was '37', then-                 to update the post, the command would be:-                 .-                 >     BlogLiterately --postid=37 http://blogurl.example.com/xmlrpc.php \-                 >         myname mypasswd "Sample" Sample.lhs-                 .-                 and the post will be updated with the new text.-                 .-                 References:-                 .-                   1. <http://daringfireball.net/projects/markdown/>-                 .-                   2. <http://johnmacfarlane.net/pandoc/>--Cabal-Version:  >= 1.5-Homepage:       none-License:        GPL-License-file:   LICENSE-Category:	Web-Copyright:	Copyright (c) Robert Greayer 2008.-Author:         Robert Greayer <robgreayer@yahoo.com>-Maintainer:	Robert Greayer <robgreayer@yahoo.com>-Stability:	experimental-Build-Type:     Simple-Tested-With:	GHC ==6.10.4-Extra-Source-Files: hscolour.css-                    kate.css-Executable BlogLiterately-  Build-Depends:  base >= 4.0 && < 4.2, haskell98, parsec >= 2.1.0.0 && < 3,-                  HaXml >= 1.13 && < 1.19, utf8-string >= 0.3 && < 0.4,-                  hscolour >= 1.15 && < 1.16, xhtml >= 3000.2 && < 3000.3, cmdargs >= 0.1 && < 0.2,-                  haxr >= 3000.2.1 && < 3000.3, pandoc >= 1.2 && < 1.3-  Main-Is:        BlogLiterately.lhs-  Hs-Source-Dirs: src-  Ghc-Options: -fwarn-unused-imports+Name:           BlogLiterately
+Version:        0.3
+Synopsis:	A tool for posting Haskelly articles to blogs
+
+Description:     BlogLiterately is a tool for uploading web log posts to web log servers
+                 that support the MetaWeblog API (such as WordPress-based blogs and many
+                 others).  Blog posts to be published via BlogLiterately are written in
+                 markdown [1] format, with extensions supported by pandoc [2].  Posts may be
+                 actual 'bird-style' literate Haskell files, with commentary in markdown.
+                 Code segments (including actual source lines from literate haskell files,
+                 as well as markdown code blocks) may be syntax-highlighted in the resulting
+                 HTML that is posted to the blog.  There are two types (two different
+                 libraries used) of formatting available for formatting code segments.
+                 .
+                   * Hscolour (for formatting Haskell code segments)
+                 .
+                   * highlighting-kate (for formatting Haskell and non-haskell segments)
+                 .
+                 The Markdown webpage has information about markdown formatting options,
+                 and the Pandoc website has information about the extensions supported.
+                 BlogLiterately extends the notation a bit further, for specifying code
+                 segments.  In basic markdown, A code segment is set off from normal
+                 text via indentation, e.g.:
+                 .
+                 >   -- This is a code segment but the tool doesn't know what kind!
+                 >   foo :: String -> String
+                 .
+                 Pandoc offers another way to specify a code segment (replace the
+                 square braces with curly braces, haddock/hackage mangles them):
+                 .
+                 > ~~~~ [ .haskell ] 
+                 > -- This is a code segment, and the tool knows it's Haskell!
+                 > foo :: String -> String 
+                 > ~~~~
+                 .
+                 BlogLiterately lets you specify a Haskell segment this way (this is
+                 just a normal markdown indented code block with an extra tag at
+                 the top.  In either the above way of specifying the type of code
+                 in the block, you may specify other kinds of code besides haskell,
+                 e.g. cpp, bash, java, ml, eiffel, etc.):
+                 .
+                 >     [haskell]
+                 >     -- This is a code segment, and the tool knows it's Haskell!
+                 >     foo :: String -> String
+                 .
+                 Once you have written your markdown file, you can run the tool, specifying how
+                 you want it highlighted.  You can specify different highlighting modes for
+                 the haskell segments and the other code segments.  If using hscolour, you
+                 can specify that the highlighting be done 'inline' via CSS 'style'
+                 attributes.  You can use the default styling (which is similar to source
+                 code in documentation on hackage) or you can specify a configuration file
+                 which looks something like this:
+                 .
+                 >     [("hs-keyword","color: blue; font-weight: bold;")
+                 >     , ("hs-keyglyph","color: red;")
+                 >     , ("hs-layout","color: red;")
+                 >     , ("hs-comment","color: green;")
+                 >     , ("hs-conid", "")
+                 >     , ("hs-varid", "")
+                 >     , ("hs-conop", "")
+                 >     , ("hs-varop", "")
+                 >     , ("hs-str", "color: teal;")
+                 >     , ("hs-chr", "color: teal;")
+                 >     , ("hs-number", "")
+                 >     , ("hs-cpp", "")
+                 >     , ("hs-selection", "")
+                 >     , ("hs-variantselection", "")
+                 >     , ("hs-definition", "")]
+                 .
+                 It has to be (readable as) a Haskell value of type [(String,String)],
+                 and it will only have an effect if you use the above class names (e.g.
+                 'hs-keyword' to specify a style for Haskell keywords).
+                 .
+                 With highlighting-kate (always) and with hscolour
+                 (optionally), the style for syntax segments is specified using 'class'
+                 attributes, so the stylesheet must be provided separately.  Sample 
+                 stylesheets are provided in the package archive file.
+                 .
+                 To use the highlighting-kate, you must (re)install Pandoc with highlighting
+                 enabled, like so:
+                 .
+                 > cabal install -fhighlighting pandoc
+                 .
+                 or
+                 .
+                 > cabal install --reinstall -fhighlighting pandoc
+                 .
+                 (If you have already installed BlogLiterately, you must reinstall that
+                 as well).
+                 .
+                 The options for BlogLiterately are, I hope, self-explanatory (given the 
+                 above background!).  Note that if Pandoc isn't installed with highlighting
+                 enabled, there will be fewer options (no -kate options):
+                 .
+                 > BlogLierately v0.3, (C) Robert Greayer 2009
+                 > This program comes with ABSOLUTELY NO WARRANTY
+                 > 
+                 > 
+                 > BlogLiterately [FLAG] URL USER PASSWORD TITLE FILE
+                 > 
+                 >   -? --help[=FORMAT]    Show usage information (optional format)
+                 >   -V --version          Show version information
+                 >   -v --verbose          Higher verbosity
+                 >   -q --quiet            Lower verbosity
+                 >   -t --test             do a test-run: html goes to stdout, is not posted
+                 >   -s --style=FILE       Style Specification (for --hscolour-icss)
+                 >      --hscolour-icss    hilight haskell: hscolour, inline style (default)
+                 >      --hscolour-css     hilight haskell: hscolour, separate stylesheet
+                 >      --hs-nohilight     no haskell hilighting
+                 >      --hs-kate          hilight haskell with highlighting-kate
+                 >      --other-code-kate  hilight other code with highlighting-kate
+                 >      --publish          Publish post (otherwise it's uploaded as a draft)
+                 >      --category=VALUE   post category (can specify more than one)
+                 >   -b --blogid=VALUE     Blog specific identifier (default=default)
+                 >      --postid=VALUE     Post to replace (if any)
+                 .
+                 .
+                 To post to a WordPress blog, the command is:
+                 .
+                 >     BlogLiterately http://blogurl.example.com/xmlrpc.php \
+                 >         myname mypasswd "Sample" Sample.lhs
+                 .
+                 (which creates a new post).  If, for example, the post id of that post
+                 (which BlogLiterately prints when it uploads a new post) was '37', then
+                 to update the post, the command would be:
+                 .
+                 >     BlogLiterately --postid=37 http://blogurl.example.com/xmlrpc.php \
+                 >         myname mypasswd "Sample" Sample.lhs
+                 .
+                 and the post will be updated with the new text.
+                 .
+                 References:
+                 .
+                   1. <http://daringfireball.net/projects/markdown/>
+                 .
+                   2. <http://johnmacfarlane.net/pandoc/>
+
+Cabal-Version:  >= 1.5
+Homepage:       none
+License:        GPL
+License-file:   LICENSE
+Category:	Web
+Copyright:	Copyright (c) Robert Greayer 2008.
+Author:         Robert Greayer <robgreayer@yahoo.com>
+Maintainer:	Robert Greayer <robgreayer@yahoo.com>
+Stability:	experimental
+Build-Type:     Simple
+Tested-With:	GHC ==6.10.4
+Extra-Source-Files: hscolour.css
+                    kate.css
+Executable BlogLiterately
+  Build-Depends:  base >= 4.0 && < 4.3, haskell98, parsec >= 2.1.0.0 && < 3,
+                  HaXml >= 1.20 && < 1.21, utf8-string >= 0.3 && < 0.4,
+                  hscolour >= 1.15 && < 1.17, xhtml >= 3000.2 && < 3000.3, cmdargs >= 0.1 && < 0.2,
+                  haxr >= 3000.2.1 && < 3000.6, pandoc >= 1.2 && < 1.6
+  Main-Is:        BlogLiterately.lhs
+  Hs-Source-Dirs: src
+  Ghc-Options: -fwarn-unused-imports
hscolour.css view
@@ -1,6 +1,6 @@-.hs-keyglyph, .hs-layout {color: red;}-.hs-keyword {color: blue;}-.hs-comment, .hs-comment a {color: green;}-.hs-str, .hs-chr {color: teal;}-.hs-keyword,.hs-conid, .hs-varid, .hs-conop, .hs-varop {}-.hs-num, .hs-cpp, .hs-sel, .hs-definition {}+.hs-keyglyph, .hs-layout {color: red;}
+.hs-keyword {color: blue;}
+.hs-comment, .hs-comment a {color: green;}
+.hs-str, .hs-chr {color: teal;}
+.hs-keyword,.hs-conid, .hs-varid, .hs-conop, .hs-varop {}
+.hs-num, .hs-cpp, .hs-sel, .hs-definition {}
kate.css view
@@ -1,7 +1,7 @@-/* this file was derived from highlighting-kate which is Copyright-   John MacFarlane.  Approximately the same file, along with other -   stylesheets, are available in the highlighting-kate package on-   hackage. */+/* this file was derived from highlighting-kate which is Copyright
+   John MacFarlane.  Approximately the same file, along with other 
+   stylesheets, are available in the highlighting-kate package on
+   hackage. */
 table.sourceCode, tr.sourceCode, td.lineNumbers, td.sourceCode, table.sourceCode pre 
    { margin: 0; padding: 0; border: 0; vertical-align: baseline; border: none; }
 td.lineNumbers { border-right: 1px solid #AAAAAA; text-align: right; color: #AAAAAA; padding-right: 5px; padding-left: 5px; }
src/BlogLiterately.lhs view
@@ -1,472 +1,473 @@-This new version of BlogLiterately adds a few more options and tries to allow-the user to take advantage of the Pandoc syntax highlighting, or suppress-it.--> {-# LANGUAGE DeriveDataTypeable #-}-> module Main where--We need [Pandoc][] for parsing [Markdown][]:--> import Text.Pandoc-> import Text.Pandoc.Highlighting--And [hscolour][] for highlighting:--> import Language.Haskell.HsColour(hscolour,Output(..))-> import Language.Haskell.HsColour.Colourise(defaultColourPrefs)--To post to a blog, we need the [MetaWeblog][] API, which is an XML-RPC-based-protocol for interacting with blogs.--We'll use the Haskell XML-RPC library, [HaXR][], by Bjorn Bringert, (on -[hackage][hackage-haxr]). *Note: the latest version (as of this writing) of -HaXR on Hackage does not specify an upper bound in its dependency on HaXml, but-it is incompatible with the 1.19 versions of HaXml!  If you have HaXml-1.19.* -installed, you'll have to work around this.*--> import Network.XmlRpc.Client-> import Network.XmlRpc.Internals--And it works that out I'll need some miscellaneous other stuff.  Since I'm -writing a command line tool, I'll need to process the command line arguments, -and Neil Mitchell's [CmdArgs][] library ought to work for that:--> import System.Console.CmdArgs--I'm going to end up needing to parse and manipulate XHTML, so I'll use Malcolm-Wallace's [HaXml][] XML combinators:--> import Text.XML.HaXml-> import Text.XML.HaXml.Verbatim--> import qualified System.IO.UTF8 as U--> import Control.Monad(liftM,unless)-> import Text.XHtml.Transitional(showHtmlFragment)-> import Text.ParserCombinators.Parsec--The program will read in a literate Haskell file, use Pandoc to parse it as -markdown, and, if it is using hscolour to for the Haskell pieces, will use-hscolour to transform those.  Pandoc turns its input into a structure of type:--    [haskell]-    data Pandoc = Pandoc Meta [Block]-    -where a `Block` (the interesting bit, for my purposes) looks like:--    [haskell]-    -- | Block element.-    data Block  -        = Plain [Inline]        -- ^ Plain text, not a paragraph-        | Para [Inline]         -- ^ Paragraph-        | CodeBlock Attr String -- ^ Code block (literal) with attributes -        | RawHtml String        -- ^ Raw HTML block (literal)-        | BlockQuote [Block]    -- ^ Block quote (list of blocks)-        | OrderedList ListAttributes [[Block]] -- ^ Ordered list (attributes-                                -- and a list of items, each a list of blocks)-        | BulletList [[Block]]  -- ^ Bullet list (list of items, each-                                -- a list of blocks)-        | DefinitionList [([Inline],[Block])]  -- ^ Definition list -                                -- (list of items, each a pair of an inline list,-                                -- the term, and a block list)-        | Header Int [Inline]   -- ^ Header - level (integer) and text (inlines) -        | HorizontalRule        -- ^ Horizontal rule-        | Table [Inline] [Alignment] [Double] [[Block]] [[[Block]]]  -- ^ Table,-                                -- with caption, column alignments,-                                -- relative column widths, column headers-                                -- (each a list of blocks), and rows-                                -- (each a list of lists of blocks)-        | Null                  -- ^ Nothing-        deriving (Eq, Read, Show, Typeable, Data)--The literate Haskell that Pandoc finds in a file ends up in various `CodeBlock`-elements of the `Pandoc` document.  Other code can also wind up in `CodeBlock`-elements -- normal markdown formatted code.  The `Attr` component has -metadata about what's in the code block:--    [haskell]-    type Attr = (String, -- code block identifier-                     [String], -- list of code classes-                     [(String, String)]) -- name/value pairs--Thanks to some feedback from the Pandoc author, John MacFarlane, I learned that-the CodeBlock *may* contain markers about the kind of code contained within the-block.  LHS (bird-style or LaTex style) will always have an `Attr` of the form-`("",["sourceCode","haskell"],[])`, and other `CodeBlock`-elements are the markdown code blocks *may* have an identifier, classes, or -key/value pairs.  Pandoc captures this info when the file contains code blocks-in the delimited (rather than indented) format, which allows an optional -meta-data specification, e.g.--~~~~~~~~~~~-~~~~~~~ { .bash }-x=$1-echo $x-~~~~~~~-~~~~~~~~~~~--Although Pandoc supports the above format for marking code blocks (and -annotating the kind of code within the block) I'll also keep my notation as-another option for use with indented blocks, i.e. if you write:--<pre><code>-    [haskell]-    foo :: String -> String-</code></pre>--it is a Haskell block.  If it looks like something else, e.g.--<pre><code>-    [cpp]-    cout << "Hello World!";-</code></pre>--or-<pre><code>-    [other]-    foo bar baz-</pre></code>--If highlighting-kate is specified for highlighting Haskell blocks, the distinction-between the literate blocks and the delimited blocks is lost (this is simply how-the Pandoc highlighting module currently works).--I'll adopt the rule that if you specify a class or-classes using Pandoc's delimited code block syntax, I'll assume that there is -no additional tag within the block in Blog Literately syntax.  I still need my-`unTag` function to parse the code block.--> unTag :: String -> (String, String)-> unTag s = either (const ("",s)) id $ parse tag "" s->    where tag = do->              tg <- between (char '[') (char ']') $ many $ noneOf "[]"->              skipMany $ oneOf " \t"->              (string "\r\n" <|> string "\n")->              txt <- many $ anyToken->              eof->              return (tg,txt)--To highlight the syntax using hscolour (which produces HTML), I'm going to-need to transform the `String` from a `CodeBlock` element to a `String` -suitable for the `RawHtml` element (because the hscolour library transforms-Haskell text to HTML). Pandoc strips off the prepended &gt; characters from the-literate Haskell, so I need to put them back, and also tell hscolour whether the-source it is colouring is literate or not.  The hscolour function looks like:--    [haskell]-    hscolour :: Output      -- ^ Output format.-             -> ColourPrefs -- ^ Colour preferences...-             -> Bool        -- ^ Whether to include anchors.-             -> Bool        -- ^ Whether output document is partial or complete.-             -> String      -- ^ Title for output.-             -> Bool        -- ^ Whether input document is literate haskell-             -> String      -- ^ Haskell source code.-             -> String      -- ^ Coloured Haskell source code.--Since I still don't like the `ICSS` output from hscolour, I'm going to provide-two options for hscolouring to users: one that simply uses hscolour's `CSS`-format, so the user can provide definitions in their blog's stylesheet to-control the rendering, and a post-processing option to transform the `CSS`-class-based rendering into a inline style based rendering (for people who can't-update their stylesheet).  `colourIt` performs the initial transformation:--> colourIt literate srcTxt = ->     hscolour CSS defaultColourPrefs False True "" literate srcTxt'->     where srcTxt' | literate = prepend srcTxt->                   | otherwise = srcTxt-    -Prepending the literate Haskell markers on the source:--> prepend s = unlines $ map ("> " ++) $ lines s--Hscolour uses HTML `span` elements and CSS classes like 'hs-keyword' or -`hs-keyglyph` to markup Haskell code.  What I want to do is take each marked -`span` element and replace the `class` attribute with an inline `style` element-that has the markup I want for that kind of source.  I've rethought the style -preferences type, and think it will be simpler, and more general, as just a list-of name/value pairs:--> type StylePrefs = [(String,String)]--The default style that produces something like what the source listings-on Hackage look like is now:--> defaultStylePrefs = [->     ("hs-keyword","color: blue; font-weight: bold;")->   , ("hs-keyglyph","color: red;")->   , ("hs-layout","color: red;")->   , ("hs-comment","color: green;")->   , ("hs-conid", "")->   , ("hs-varid", "")->   , ("hs-conop", "")->   , ("hs-varop", "")->   , ("hs-str", "color: teal;")->   , ("hs-chr", "color: teal;")->   , ("hs-number", "")->   , ("hs-cpp", "")->   , ("hs-selection", "")->   , ("hs-variantselection", "")->   , ("hs-definition", "")]--I can read these preferences in from a file using the `Read` instance for-`StylePrefs`.  I could handle errors better, but this should work:--> getStylePrefs "" = return defaultStylePrefs-> getStylePrefs fname = liftM read (U.readFile fname)--Hscolour produces a `String` of HTML.  To 'bake' the styles into-the HTML it, we need to parse it, manipulate it-and then re-render it as a `String`.  Use HaXml to do all of this:--> bakeStyles :: StylePrefs -> String -> String-> bakeStyles prefs s =  verbatim $ filtDoc (xmlParse "bake-input" s) where->     -- filter the document (an Hscoloured fragment of Haskell source)->     filtDoc (Document p s e m) =  c where->         [c] = filts (CElem e)->     -- the filter is a fold of individual filters for each CSS class->     filts = mkElem "pre" [(foldXml $ foldl o keep $ map filt prefs) `o` replaceTag "code"]->     -- an individual filter replaces the attributes of a tag with->     -- a style attribute when it has a specific 'class' attribute.->     filt (cls,style) =->         replaceAttrs [("style",style)] `when`->             (attrval $ ("class",AttValue [Left cls]))--Highlighting-Kate uses &lt;br/> in code blocks to indicate newlines.  WordPress-(if not other software) chooses to strip them away when found in &lt;pre> sections-of uploaded HTML.  So need to turn them back to newlines.--> replaceBreaks :: String -> String-> replaceBreaks s = verbatim $ filtDoc (xmlParse "input" s) where->    -- filter the document (a highlighting-kate hitlited fragment of->    -- haskell source->    filtDoc (Document p s e m) = c where->        [c] = filts (CElem e)->    filts = foldXml (literal "\n" `when` tag "br")--Note to self: the above is a function that could be made better in a -few ways and then factored out into a library.  A way to handle the -above would be to allow the preferences to be specified as an actual CSS-style sheet, which then would be baked into the HTML.  Such a function-could be separately useful, and could be used to 'bake' in the-highlighting-kate styles.--To completely colourise/highlight a `CodeBlock` we now can create a function-that transforms a `CodeBlock` into a `RawHtml` block, where the content contains-marked up Haskell (possibly with literate markers), or marked up non-Haskell, if-highlighting of non-Haskell has been selected.--> colouriseCodeBlock :: HsHighlight -> Bool -> Block -> Block-> colouriseCodeBlock hsHilite otherHilite b@(CodeBlock attr@(_,classes,_) s) =->     if tag == "haskell" || haskell->         then case hsHilite of->             HsColourInline style -> ->                 RawHtml $ bakeStyles style $ colourIt lit src->             HsColourCSS -> RawHtml $ colourIt lit src->             HsNoHighlight -> RawHtml $ simpleHTML hsrc->             HsKate -> if null tag ->                 then myHiliteK attr hsrc->                 else myHiliteK ("",tag:classes,[]) hsrc->         else if otherHilite->             then case tag of->                 "" -> myHiliteK attr src->                 t -> myHiliteK ("",[t],[]) src->             else RawHtml $ simpleHTML src     ->     where (tag,src) = if null classes then unTag s else ("",s)->           hsrc = if lit then prepend src else src->           lit = "sourceCode" `elem` classes->           haskell = "haskell" `elem` classes->           simpleHTML s = "<pre><code>" ++ s ++ "</code></pre>"->           myHiliteK attr s = case highlightHtml attr s of->               Left _ -> RawHtml $ simpleHTML s->               Right html -> RawHtml $ replaceBreaks $ showHtmlFragment html-> colouriseCodeBlock _ _ b = b--Colourising a `Pandoc` document is simply:--> colourisePandoc hsHilite otherHilite (Pandoc m blocks) = ->     Pandoc m $ map (colouriseCodeBlock hsHilite otherHilite) blocks--Transforming a complete input document string to an HTML output string:--> xformDoc :: HsHighlight -> Bool -> String -> String-> xformDoc hsHilite otherHilite s = ->     showHtmlFragment ->     $ writeHtml writeOpts -- from Pandoc->     $ colourisePandoc hsHilite otherHilite->     $ readMarkdown parseOpts -- from Pandoc->     $ fixLineEndings s->     where writeOpts = defaultWriterOptions {->               --writerLiterateHaskell = True,->               writerReferenceLinks = True }->           parseOpts = defaultParserState { ->               stateLiterateHaskell = True }->           -- readMarkdown is picky about line endings->           fixLineEndings [] = []->           fixLineEndings ('\r':'\n':cs) = '\n':fixLineEndings cs->           fixLineEndings (c:cs) = c:fixLineEndings cs---The metaWeblog API defines a `newPost` and  `editPost` procedures that look-like:--    [other]-    metaWeblog.newPost (blogid, username, password, struct, publish)-        returns string-    metaWeblog.editPost (postid, username, password, struct, publish)-        returns true--For my blog (a WordPress blog), the `blogid` is just `default`.  The user-name and password are simply strings, and `publish` is a flag indicating whether-to load the post as a draft, or to make it public immediately.  The `postid` is-an identifier string which is assigned when you initially create a post. The-interesting bit is the `struct` field, which is an XML-RPC structure defining -the post along with some meta-data, like the title.  I want be able to provide-the post body, a title, and a list of categories.  The for the-body and title, we could just let HaXR convert the values automatically-into the XML-RPC `Value` type, since they all have the same Haskell type-(`String`) and thus can be put into a list.  But the categories are a list of-strings, so we need to explicitly convert everything to a `Value`, then combine:--> mkPost title text categories = ->     cats ++ [("title",toValue title),("description",toValue text)]->     where cats = if null categories then [] ->               else [("categories",toValue categories)]--The HaXR library exports a function for invoking XML-RPC procedures:--    [haskell]-    remote :: Remote a => -        String -- ^ Server URL. May contain username and password on-               --   the format username:password\@ before the hostname.-           -> String -- ^ Remote method name.-           -> a      -- ^ Any function -         -- @(XmlRpcType t1, ..., XmlRpcType tn, XmlRpcType r) => -                     -- t1 -> ... -> tn -> IO r@--The function requires an URL and a method name, and returns a function of type-`Remote a => a`.  Based on the instances defined for `Remote`, any function-with zero or more parameters in the class `XmlRpcType` and a return type of-`XmlRpcType r => IO r` will work, which means you can simply 'feed' `remote`-additional arguments as required by the remote procedure, and as long as you-make the call in an IO context, it will typecheck.  So to call the-`metaWeblog.newPost` procedure, I can do something like:--> postIt :: String -> String -> String -> String -> String -> String ->     -> [String] -> Bool -> IO String-> postIt url blogId user password title text cats publish =->     remote url "metaWeblog.newPost" blogId user password ->         (mkPost title text cats) publish--To update (replace) a post, the function would be:--> updateIt :: String -> String -> String -> String -> String -> String ->     -> [String] -> Bool -> IO Bool-> updateIt url postId user password title text cats publish =->     remote url "metaWeblog.editPost" postId user password->         (mkPost title text cats) publish--There are four modes of Haskell highlighting:--> data HsHighlight = HsColourInline { hsStylePrefs :: StylePrefs }->     | HsColourCSS | HsKate | HsNoHighlight->     deriving (Data,Typeable,Show,Eq)--And two modes for other code (off or on!).--We can figure out if Pandoc is linked with highlighting-kate (we-won't show the kate-related options if it isn't):--> noKate = null defaultHighlightingCss--To create a command line program,  I can capture the command line controls in a type:--> data BlogLiterately = BlogLiterately {->        test :: Bool,       -- do a dry-run: html goes to stdout->        style :: String,    -- name of a style file->        hshighlight :: HsHighlight,->        highlightOther :: Bool, -- use highlight-kate to highlight other code->        publish :: Bool,    -- an indication of whether the post should be->                                -- published, or loaded as a draft->        categories :: [String], --->        blogid :: String,   -- blog-specific identifier (e.g. for blogging->                                -- software handling multiple blogs)->        blog :: String,     -- blog xmlrpc URL->        user :: String,     -- blog user name->        password :: String, -- blog password->        title :: String,    -- post title->        file :: String,     -- file to post->        postid :: String    -- id of a post to updated->     } deriving (Show,Data,Typeable)--And using CmdArgs, this bit of impure evil defines how the command line arguments-work:--> bl = mode $ BlogLiterately {->     test = def &= text "do a test-run: html goes to stdout, is not posted",->     style = "" &= text "Style Specification (for --hscolour-icss)" & typFile,->     hshighlight = enum (HsColourInline defaultStylePrefs)->         ([ (HsColourInline defaultStylePrefs) &= explicit & ->                flag "hscolour-icss" & text inline,->            HsColourCSS &= explicit & flag "hscolour-css" & text css,->            HsNoHighlight &= explicit & flag "hs-nohilight" &->                text "no haskell hilighting" ] ++->           (if noKate then []  else->                [HsKate &= explicit & flag "hs-kate" & text hskate])),->     highlightOther = enum False ->         (if noKate then [] else ->              [True &= explicit & flag "other-code-kate" &->               text "hilight other code with highlighting-kate"]),->     publish = def &= text "Publish post (otherwise it's uploaded as a draft)",->     categories = def &= explicit & flag "category" & ->         text "post category (can specify more than one)",->     blogid = "default" &= text "Blog specific identifier",->     blog = def &= argPos 0 & typ "URL" ->         & text "URL of blog's xmlrpc address (e.g. http://example.com/blog/xmlrpc.php)",->     user = def &= argPos 1 & typ "USER" & text "blog author's user name" ,->     password = def &= argPos 2 & typ "PASSWORD" & text "blog author's password",->     title = def &= argPos 3 & typ "TITLE",->     file = def &=  argPos 4 & typ "FILE" & text "literate haskell file",->     postid = "" &= text "Post to replace (if any)" } where->     inline =  "hilight haskell: hscolour, inline style (default)"->     css = "hilight haskell: hscolour, separate stylesheet"->     hskate = "hilight haskell with highlighting-kate"--The main blogging function uses the information captured in the `BlogLiterately`-type to read the style preferences, read the input file and transform it, and-post it to the blog:--> blogLiterately (BlogLiterately test style hsmode other pub cats blogid url->         user pw title file postid) = do->     prefs <- getStylePrefs style->     let hsmode' = case hsmode of->             HsColourInline _ -> HsColourInline prefs->             _ -> hsmode->     html <- liftM (xformDoc hsmode' other) $ U.readFile file->     if test->        then putStr html->        else if null postid ->            then do->                postid <- postIt url blogid user pw title html cats pub->                putStrLn $ "post Id: " ++ postid->            else do->                result <- updateIt url postid user pw title html cats pub->                unless result $ putStrLn "update failed!"--And the main program is simply:--> main = cmdArgs info [bl] >>= blogLiterately->    where info = "BlogLierately v0.2, (C) Robert Greayer 2009\n" ++->                 "This program comes with ABSOLUTELY NO WARRANTY\n"--I can run it to get some help:--[markdown]: http://daringfireball.net/projects/markdown/-[pandoc]: http://johnmacfarlane.net/pandoc/ "Pandoc"-[hackage]: http://hackage.haskell.org/packages/hackage.html-[haddock]: http://www.haskell.org/haddock/-[hscolour]: http://www.cs.york.ac.uk/fp/darcs/hscolour/-[metaweblog]: http://www.xmlrpc.com/metaWeblogApi-[haxr]: http://www.haskell.org/haxr/-[hackage-haxr]: http://hackage.haskell.org/package/haxr-[cmdargs]: http://community.haskell.org/~ndm/cmdargs/-[haxml]: http://www.cs.york.ac.uk/fp/HaXml/+This new version of BlogLiterately adds a few more options and tries to allow
+the user to take advantage of the Pandoc syntax highlighting, or suppress
+it.
+
+> {-# LANGUAGE DeriveDataTypeable #-}
+> module Main where
+
+We need [Pandoc][] for parsing [Markdown][]:
+
+> import Text.Pandoc
+> import Text.Pandoc.Highlighting
+
+And [hscolour][] for highlighting:
+
+> import Language.Haskell.HsColour(hscolour,Output(..))
+> import Language.Haskell.HsColour.Colourise(defaultColourPrefs)
+
+To post to a blog, we need the [MetaWeblog][] API, which is an XML-RPC-based
+protocol for interacting with blogs.
+
+We'll use the Haskell XML-RPC library, [HaXR][], by Bjorn Bringert, (on 
+[hackage][hackage-haxr]). *Note: the latest version (as of this writing) of 
+HaXR on Hackage does not specify an upper bound in its dependency on HaXml, but
+it is incompatible with the 1.19 versions of HaXml!  If you have HaXml-1.19.* 
+installed, you'll have to work around this.*
+
+> import Network.XmlRpc.Client
+> import Network.XmlRpc.Internals
+
+And it works that out I'll need some miscellaneous other stuff.  Since I'm 
+writing a command line tool, I'll need to process the command line arguments, 
+and Neil Mitchell's [CmdArgs][] library ought to work for that:
+
+> import System.Console.CmdArgs
+
+I'm going to end up needing to parse and manipulate XHTML, so I'll use Malcolm
+Wallace's [HaXml][] XML combinators:
+
+> import Text.XML.HaXml
+> import Text.XML.HaXml.Posn
+> import Text.XML.HaXml.Verbatim
+
+> import qualified System.IO.UTF8 as U
+
+> import Control.Monad(liftM,unless)
+> import Text.XHtml.Transitional(showHtmlFragment)
+> import Text.ParserCombinators.Parsec
+
+The program will read in a literate Haskell file, use Pandoc to parse it as 
+markdown, and, if it is using hscolour to for the Haskell pieces, will use
+hscolour to transform those.  Pandoc turns its input into a structure of type:
+
+    [haskell]
+    data Pandoc = Pandoc Meta [Block]
+    
+where a `Block` (the interesting bit, for my purposes) looks like:
+
+    [haskell]
+    -- | Block element.
+    data Block  
+        = Plain [Inline]        -- ^ Plain text, not a paragraph
+        | Para [Inline]         -- ^ Paragraph
+        | CodeBlock Attr String -- ^ Code block (literal) with attributes 
+        | RawHtml String        -- ^ Raw HTML block (literal)
+        | BlockQuote [Block]    -- ^ Block quote (list of blocks)
+        | OrderedList ListAttributes [[Block]] -- ^ Ordered list (attributes
+                                -- and a list of items, each a list of blocks)
+        | BulletList [[Block]]  -- ^ Bullet list (list of items, each
+                                -- a list of blocks)
+        | DefinitionList [([Inline],[Block])]  -- ^ Definition list 
+                                -- (list of items, each a pair of an inline list,
+                                -- the term, and a block list)
+        | Header Int [Inline]   -- ^ Header - level (integer) and text (inlines) 
+        | HorizontalRule        -- ^ Horizontal rule
+        | Table [Inline] [Alignment] [Double] [[Block]] [[[Block]]]  -- ^ Table,
+                                -- with caption, column alignments,
+                                -- relative column widths, column headers
+                                -- (each a list of blocks), and rows
+                                -- (each a list of lists of blocks)
+        | Null                  -- ^ Nothing
+        deriving (Eq, Read, Show, Typeable, Data)
+
+The literate Haskell that Pandoc finds in a file ends up in various `CodeBlock`
+elements of the `Pandoc` document.  Other code can also wind up in `CodeBlock`
+elements -- normal markdown formatted code.  The `Attr` component has 
+metadata about what's in the code block:
+
+    [haskell]
+    type Attr = (String, -- code block identifier
+                     [String], -- list of code classes
+                     [(String, String)]) -- name/value pairs
+
+Thanks to some feedback from the Pandoc author, John MacFarlane, I learned that
+the CodeBlock *may* contain markers about the kind of code contained within the
+block.  LHS (bird-style or LaTex style) will always have an `Attr` of the form
+`("",["sourceCode","haskell"],[])`, and other `CodeBlock`
+elements are the markdown code blocks *may* have an identifier, classes, or 
+key/value pairs.  Pandoc captures this info when the file contains code blocks
+in the delimited (rather than indented) format, which allows an optional 
+meta-data specification, e.g.
+
+~~~~~~~~~~~
+~~~~~~~ { .bash }
+x=$1
+echo $x
+~~~~~~~
+~~~~~~~~~~~
+
+Although Pandoc supports the above format for marking code blocks (and 
+annotating the kind of code within the block) I'll also keep my notation as
+another option for use with indented blocks, i.e. if you write:
+
+<pre><code>
+    [haskell]
+    foo :: String -> String
+</code></pre>
+
+it is a Haskell block.  If it looks like something else, e.g.
+
+<pre><code>
+    [cpp]
+    cout << "Hello World!";
+</code></pre>
+
+or
+<pre><code>
+    [other]
+    foo bar baz
+</pre></code>
+
+If highlighting-kate is specified for highlighting Haskell blocks, the distinction
+between the literate blocks and the delimited blocks is lost (this is simply how
+the Pandoc highlighting module currently works).
+
+I'll adopt the rule that if you specify a class or
+classes using Pandoc's delimited code block syntax, I'll assume that there is 
+no additional tag within the block in Blog Literately syntax.  I still need my
+`unTag` function to parse the code block.
+
+> unTag :: String -> (String, String)
+> unTag s = either (const ("",s)) id $ parse tag "" s
+>    where tag = do
+>              tg <- between (char '[') (char ']') $ many $ noneOf "[]"
+>              skipMany $ oneOf " \t"
+>              (string "\r\n" <|> string "\n")
+>              txt <- many $ anyToken
+>              eof
+>              return (tg,txt)
+
+To highlight the syntax using hscolour (which produces HTML), I'm going to
+need to transform the `String` from a `CodeBlock` element to a `String` 
+suitable for the `RawHtml` element (because the hscolour library transforms
+Haskell text to HTML). Pandoc strips off the prepended &gt; characters from the
+literate Haskell, so I need to put them back, and also tell hscolour whether the
+source it is colouring is literate or not.  The hscolour function looks like:
+
+    [haskell]
+    hscolour :: Output      -- ^ Output format.
+             -> ColourPrefs -- ^ Colour preferences...
+             -> Bool        -- ^ Whether to include anchors.
+             -> Bool        -- ^ Whether output document is partial or complete.
+             -> String      -- ^ Title for output.
+             -> Bool        -- ^ Whether input document is literate haskell
+             -> String      -- ^ Haskell source code.
+             -> String      -- ^ Coloured Haskell source code.
+
+Since I still don't like the `ICSS` output from hscolour, I'm going to provide
+two options for hscolouring to users: one that simply uses hscolour's `CSS`
+format, so the user can provide definitions in their blog's stylesheet to
+control the rendering, and a post-processing option to transform the `CSS`
+class-based rendering into a inline style based rendering (for people who can't
+update their stylesheet).  `colourIt` performs the initial transformation:
+
+> colourIt literate srcTxt = 
+>     hscolour CSS defaultColourPrefs False True "" literate srcTxt'
+>     where srcTxt' | literate = prepend srcTxt
+>                   | otherwise = srcTxt
+    
+Prepending the literate Haskell markers on the source:
+
+> prepend s = unlines $ map ("> " ++) $ lines s
+
+Hscolour uses HTML `span` elements and CSS classes like 'hs-keyword' or 
+`hs-keyglyph` to markup Haskell code.  What I want to do is take each marked 
+`span` element and replace the `class` attribute with an inline `style` element
+that has the markup I want for that kind of source.  I've rethought the style 
+preferences type, and think it will be simpler, and more general, as just a list
+of name/value pairs:
+
+> type StylePrefs = [(String,String)]
+
+The default style that produces something like what the source listings
+on Hackage look like is now:
+
+> defaultStylePrefs = [
+>     ("hs-keyword","color: blue; font-weight: bold;")
+>   , ("hs-keyglyph","color: red;")
+>   , ("hs-layout","color: red;")
+>   , ("hs-comment","color: green;")
+>   , ("hs-conid", "")
+>   , ("hs-varid", "")
+>   , ("hs-conop", "")
+>   , ("hs-varop", "")
+>   , ("hs-str", "color: teal;")
+>   , ("hs-chr", "color: teal;")
+>   , ("hs-number", "")
+>   , ("hs-cpp", "")
+>   , ("hs-selection", "")
+>   , ("hs-variantselection", "")
+>   , ("hs-definition", "")]
+
+I can read these preferences in from a file using the `Read` instance for
+`StylePrefs`.  I could handle errors better, but this should work:
+
+> getStylePrefs "" = return defaultStylePrefs
+> getStylePrefs fname = liftM read (U.readFile fname)
+
+Hscolour produces a `String` of HTML.  To 'bake' the styles into
+the HTML it, we need to parse it, manipulate it
+and then re-render it as a `String`.  Use HaXml to do all of this:
+
+> bakeStyles :: StylePrefs -> String -> String
+> bakeStyles prefs s =  verbatim $ filtDoc (xmlParse "bake-input" s) where
+>     -- filter the document (an Hscoloured fragment of Haskell source)
+>     filtDoc (Document p s e m) =  c where
+>         [c] = filts (CElem e noPos)
+>     -- the filter is a fold of individual filters for each CSS class
+>     filts = mkElem "pre" [(foldXml $ foldl o keep $ map filt prefs) `o` replaceTag "code"]
+>     -- an individual filter replaces the attributes of a tag with
+>     -- a style attribute when it has a specific 'class' attribute.
+>     filt (cls,style) =
+>         replaceAttrs [("style",style)] `when`
+>             (attrval $ ("class",AttValue [Left cls]))
+
+Highlighting-Kate uses &lt;br/> in code blocks to indicate newlines.  WordPress
+(if not other software) chooses to strip them away when found in &lt;pre> sections
+of uploaded HTML.  So need to turn them back to newlines.
+
+> replaceBreaks :: String -> String
+> replaceBreaks s = verbatim $ filtDoc (xmlParse "input" s) where
+>    -- filter the document (a highlighting-kate hitlited fragment of
+>    -- haskell source
+>    filtDoc (Document p s e m) = c where
+>        [c] = filts (CElem e noPos)
+>    filts = foldXml (literal "\n" `when` tag "br")
+
+Note to self: the above is a function that could be made better in a 
+few ways and then factored out into a library.  A way to handle the 
+above would be to allow the preferences to be specified as an actual CSS
+style sheet, which then would be baked into the HTML.  Such a function
+could be separately useful, and could be used to 'bake' in the
+highlighting-kate styles.
+
+To completely colourise/highlight a `CodeBlock` we now can create a function
+that transforms a `CodeBlock` into a `RawHtml` block, where the content contains
+marked up Haskell (possibly with literate markers), or marked up non-Haskell, if
+highlighting of non-Haskell has been selected.
+
+> colouriseCodeBlock :: HsHighlight -> Bool -> Block -> Block
+> colouriseCodeBlock hsHilite otherHilite b@(CodeBlock attr@(_,classes,_) s) =
+>     if tag == "haskell" || haskell
+>         then case hsHilite of
+>             HsColourInline style -> 
+>                 RawHtml $ bakeStyles style $ colourIt lit src
+>             HsColourCSS -> RawHtml $ colourIt lit src
+>             HsNoHighlight -> RawHtml $ simpleHTML hsrc
+>             HsKate -> if null tag 
+>                 then myHiliteK attr hsrc
+>                 else myHiliteK ("",tag:classes,[]) hsrc
+>         else if otherHilite
+>             then case tag of
+>                 "" -> myHiliteK attr src
+>                 t -> myHiliteK ("",[t],[]) src
+>             else RawHtml $ simpleHTML src     
+>     where (tag,src) = if null classes then unTag s else ("",s)
+>           hsrc = if lit then prepend src else src
+>           lit = "sourceCode" `elem` classes
+>           haskell = "haskell" `elem` classes
+>           simpleHTML s = "<pre><code>" ++ s ++ "</code></pre>"
+>           myHiliteK attr s = case highlightHtml attr s of
+>               Left _ -> RawHtml $ simpleHTML s
+>               Right html -> RawHtml $ replaceBreaks $ showHtmlFragment html
+> colouriseCodeBlock _ _ b = b
+
+Colourising a `Pandoc` document is simply:
+
+> colourisePandoc hsHilite otherHilite (Pandoc m blocks) = 
+>     Pandoc m $ map (colouriseCodeBlock hsHilite otherHilite) blocks
+
+Transforming a complete input document string to an HTML output string:
+
+> xformDoc :: HsHighlight -> Bool -> String -> String
+> xformDoc hsHilite otherHilite s = 
+>     showHtmlFragment 
+>     $ writeHtml writeOpts -- from Pandoc
+>     $ colourisePandoc hsHilite otherHilite
+>     $ readMarkdown parseOpts -- from Pandoc
+>     $ fixLineEndings s
+>     where writeOpts = defaultWriterOptions {
+>               --writerLiterateHaskell = True,
+>               writerReferenceLinks = True }
+>           parseOpts = defaultParserState { 
+>               stateLiterateHaskell = True }
+>           -- readMarkdown is picky about line endings
+>           fixLineEndings [] = []
+>           fixLineEndings ('\r':'\n':cs) = '\n':fixLineEndings cs
+>           fixLineEndings (c:cs) = c:fixLineEndings cs
+
+
+The metaWeblog API defines a `newPost` and  `editPost` procedures that look
+like:
+
+    [other]
+    metaWeblog.newPost (blogid, username, password, struct, publish)
+        returns string
+    metaWeblog.editPost (postid, username, password, struct, publish)
+        returns true
+
+For my blog (a WordPress blog), the `blogid` is just `default`.  The user
+name and password are simply strings, and `publish` is a flag indicating whether
+to load the post as a draft, or to make it public immediately.  The `postid` is
+an identifier string which is assigned when you initially create a post. The
+interesting bit is the `struct` field, which is an XML-RPC structure defining 
+the post along with some meta-data, like the title.  I want be able to provide
+the post body, a title, and a list of categories.  The for the
+body and title, we could just let HaXR convert the values automatically
+into the XML-RPC `Value` type, since they all have the same Haskell type
+(`String`) and thus can be put into a list.  But the categories are a list of
+strings, so we need to explicitly convert everything to a `Value`, then combine:
+
+> mkPost title text categories = 
+>     cats ++ [("title",toValue title),("description",toValue text)]
+>     where cats = if null categories then [] 
+>               else [("categories",toValue categories)]
+
+The HaXR library exports a function for invoking XML-RPC procedures:
+
+    [haskell]
+    remote :: Remote a => 
+        String -- ^ Server URL. May contain username and password on
+               --   the format username:password\@ before the hostname.
+           -> String -- ^ Remote method name.
+           -> a      -- ^ Any function 
+         -- @(XmlRpcType t1, ..., XmlRpcType tn, XmlRpcType r) => 
+                     -- t1 -> ... -> tn -> IO r@
+
+The function requires an URL and a method name, and returns a function of type
+`Remote a => a`.  Based on the instances defined for `Remote`, any function
+with zero or more parameters in the class `XmlRpcType` and a return type of
+`XmlRpcType r => IO r` will work, which means you can simply 'feed' `remote`
+additional arguments as required by the remote procedure, and as long as you
+make the call in an IO context, it will typecheck.  So to call the
+`metaWeblog.newPost` procedure, I can do something like:
+
+> postIt :: String -> String -> String -> String -> String -> String 
+>     -> [String] -> Bool -> IO String
+> postIt url blogId user password title text cats publish =
+>     remote url "metaWeblog.newPost" blogId user password 
+>         (mkPost title text cats) publish
+
+To update (replace) a post, the function would be:
+
+> updateIt :: String -> String -> String -> String -> String -> String 
+>     -> [String] -> Bool -> IO Bool
+> updateIt url postId user password title text cats publish =
+>     remote url "metaWeblog.editPost" postId user password
+>         (mkPost title text cats) publish
+
+There are four modes of Haskell highlighting:
+
+> data HsHighlight = HsColourInline { hsStylePrefs :: StylePrefs }
+>     | HsColourCSS | HsKate | HsNoHighlight
+>     deriving (Data,Typeable,Show,Eq)
+
+And two modes for other code (off or on!).
+
+We can figure out if Pandoc is linked with highlighting-kate (we
+won't show the kate-related options if it isn't):
+
+> noKate = null defaultHighlightingCss
+
+To create a command line program,  I can capture the command line controls in a type:
+
+> data BlogLiterately = BlogLiterately {
+>        test :: Bool,       -- do a dry-run: html goes to stdout
+>        style :: String,    -- name of a style file
+>        hshighlight :: HsHighlight,
+>        highlightOther :: Bool, -- use highlight-kate to highlight other code
+>        publish :: Bool,    -- an indication of whether the post should be
+>                                -- published, or loaded as a draft
+>        categories :: [String], --
+>        blogid :: String,   -- blog-specific identifier (e.g. for blogging
+>                                -- software handling multiple blogs)
+>        blog :: String,     -- blog xmlrpc URL
+>        user :: String,     -- blog user name
+>        password :: String, -- blog password
+>        title :: String,    -- post title
+>        file :: String,     -- file to post
+>        postid :: String    -- id of a post to updated
+>     } deriving (Show,Data,Typeable)
+
+And using CmdArgs, this bit of impure evil defines how the command line arguments
+work:
+
+> bl = mode $ BlogLiterately {
+>     test = def &= text "do a test-run: html goes to stdout, is not posted",
+>     style = "" &= text "Style Specification (for --hscolour-icss)" & typFile,
+>     hshighlight = enum (HsColourInline defaultStylePrefs)
+>         ([ (HsColourInline defaultStylePrefs) &= explicit & 
+>                flag "hscolour-icss" & text inline,
+>            HsColourCSS &= explicit & flag "hscolour-css" & text css,
+>            HsNoHighlight &= explicit & flag "hs-nohilight" &
+>                text "no haskell hilighting" ] ++
+>           (if noKate then []  else
+>                [HsKate &= explicit & flag "hs-kate" & text hskate])),
+>     highlightOther = enum False 
+>         (if noKate then [] else 
+>              [True &= explicit & flag "other-code-kate" &
+>               text "hilight other code with highlighting-kate"]),
+>     publish = def &= text "Publish post (otherwise it's uploaded as a draft)",
+>     categories = def &= explicit & flag "category" & 
+>         text "post category (can specify more than one)",
+>     blogid = "default" &= text "Blog specific identifier",
+>     blog = def &= argPos 0 & typ "URL" 
+>         & text "URL of blog's xmlrpc address (e.g. http://example.com/blog/xmlrpc.php)",
+>     user = def &= argPos 1 & typ "USER" & text "blog author's user name" ,
+>     password = def &= argPos 2 & typ "PASSWORD" & text "blog author's password",
+>     title = def &= argPos 3 & typ "TITLE",
+>     file = def &=  argPos 4 & typ "FILE" & text "literate haskell file",
+>     postid = "" &= text "Post to replace (if any)" } where
+>     inline =  "hilight haskell: hscolour, inline style (default)"
+>     css = "hilight haskell: hscolour, separate stylesheet"
+>     hskate = "hilight haskell with highlighting-kate"
+
+The main blogging function uses the information captured in the `BlogLiterately`
+type to read the style preferences, read the input file and transform it, and
+post it to the blog:
+
+> blogLiterately (BlogLiterately test style hsmode other pub cats blogid url
+>         user pw title file postid) = do
+>     prefs <- getStylePrefs style
+>     let hsmode' = case hsmode of
+>             HsColourInline _ -> HsColourInline prefs
+>             _ -> hsmode
+>     html <- liftM (xformDoc hsmode' other) $ U.readFile file
+>     if test
+>        then putStr html
+>        else if null postid 
+>            then do
+>                postid <- postIt url blogid user pw title html cats pub
+>                putStrLn $ "post Id: " ++ postid
+>            else do
+>                result <- updateIt url postid user pw title html cats pub
+>                unless result $ putStrLn "update failed!"
+
+And the main program is simply:
+
+> main = cmdArgs info [bl] >>= blogLiterately
+>    where info = "BlogLierately v0.3, (C) Robert Greayer 2010\n" ++
+>                 "This program comes with ABSOLUTELY NO WARRANTY\n"
+
+I can run it to get some help:
+
+[markdown]: http://daringfireball.net/projects/markdown/
+[pandoc]: http://johnmacfarlane.net/pandoc/ "Pandoc"
+[hackage]: http://hackage.haskell.org/packages/hackage.html
+[haddock]: http://www.haskell.org/haddock/
+[hscolour]: http://www.cs.york.ac.uk/fp/darcs/hscolour/
+[metaweblog]: http://www.xmlrpc.com/metaWeblogApi
+[haxr]: http://www.haskell.org/haxr/
+[hackage-haxr]: http://hackage.haskell.org/package/haxr
+[cmdargs]: http://community.haskell.org/~ndm/cmdargs/
+[haxml]: http://www.cs.york.ac.uk/fp/HaXml/