{-

Copyright (C) 2012-2017 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

-}

{-# LANGUAGE DeriveDataTypeable         #-}

{-# LANGUAGE DeriveGeneric              #-}

{-# LANGUAGE GeneralizedNewtypeDeriving #-}

{-# LANGUAGE TemplateHaskell            #-}

{- |

   Module      : Text.Pandoc.Extensions

   Copyright   : Copyright (C) 2012-2017 John MacFarlane

   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>

   Stability   : alpha

   Portability : portable

Data structures and functions for representing markup extensions.

-}

module Text.Pandoc.Extensions ( Extension(..)

                              , Extensions

                              , emptyExtensions

                              , extensionsFromList

                              , parseFormatSpec

                              , extensionEnabled

                              , enableExtension

                              , disableExtension

                              , getDefaultExtensions

                              , pandocExtensions

                              , plainExtensions

                              , strictExtensions

                              , phpMarkdownExtraExtensions

                              , githubMarkdownExtensions

                              , multimarkdownExtensions )

where

import Data.Aeson (FromJSON (..), ToJSON (..), defaultOptions)

import Data.Aeson.TH (deriveJSON)

import Data.Bits (clearBit, setBit, testBit, (.|.))

import Data.Data (Data)

import Data.Typeable (Typeable)

import GHC.Generics (Generic)

import Text.Pandoc.Shared (safeRead)

import Text.Parsec

newtype Extensions = Extensions Integer

  deriving (Show, Read, Eq, Ord, Data, Typeable, Generic, ToJSON, FromJSON)

instance Monoid Extensions where

  mempty = Extensions 0

  mappend (Extensions a) (Extensions b) = Extensions (a .|. b)

extensionsFromList :: [Extension] -> Extensions

extensionsFromList = foldr enableExtension emptyExtensions

emptyExtensions :: Extensions

emptyExtensions = Extensions 0

extensionEnabled :: Extension -> Extensions -> Bool

extensionEnabled x (Extensions exts) = testBit exts (fromEnum x)

enableExtension :: Extension -> Extensions -> Extensions

enableExtension x (Extensions exts) = Extensions (setBit exts (fromEnum x))

disableExtension :: Extension -> Extensions -> Extensions

disableExtension x (Extensions exts) = Extensions (clearBit exts (fromEnum x))

-- | Individually selectable syntax extensions.

data Extension =

      Ext_abbreviations       -- ^ PHP markdown extra abbreviation definitions

    | Ext_all_symbols_escapable  -- ^ Make all non-alphanumerics escapable

    | Ext_amuse -- ^ Enable Text::Amuse extensions to Emacs Muse markup

    | Ext_angle_brackets_escapable  -- ^ Make < and > escapable

    | Ext_ascii_identifiers   -- ^ ascii-only identifiers for headers

    | Ext_auto_identifiers    -- ^ Automatic identifiers for headers

    | Ext_autolink_bare_uris  -- ^ Make all absolute URIs into links

    | Ext_backtick_code_blocks    -- ^ GitHub style ``` code blocks

    | Ext_blank_before_blockquote -- ^ Require blank line before a blockquote

    | Ext_blank_before_header     -- ^ Require blank line before a header

    | Ext_bracketed_spans         -- ^ Bracketed spans with attributes

    | Ext_citations           -- ^ Pandoc/citeproc citations

    | Ext_compact_definition_lists  -- ^ Definition lists without space between items,

                                    --   and disallow laziness

    | Ext_definition_lists    -- ^ Definition lists as in pandoc, mmd, php

    | Ext_east_asian_line_breaks  -- ^ Newlines in paragraphs are ignored between

                                  --   East Asian wide characters

    | Ext_emoji               -- ^ Support emoji like :smile:

    | Ext_empty_paragraphs -- ^ Allow empty paragraphs

    | Ext_epub_html_exts      -- ^ Recognise the EPUB extended version of HTML

    | Ext_escaped_line_breaks     -- ^ Treat a backslash at EOL as linebreak

    | Ext_example_lists       -- ^ Markdown-style numbered examples

    | Ext_fancy_lists         -- ^ Enable fancy list numbers and delimiters

    | Ext_fenced_code_attributes  -- ^ Allow attributes on fenced code blocks

    | Ext_fenced_code_blocks  -- ^ Parse fenced code blocks

    | Ext_fenced_divs             -- ^ Allow fenced div syntax :::

    | Ext_footnotes           -- ^ Pandoc/PHP/MMD style footnotes

    | Ext_four_space_rule     -- ^ Require 4-space indent for list contents

    | Ext_gfm_auto_identifiers  -- ^ Automatic identifiers for headers, using

                                --  GitHub's method for generating identifiers

    | Ext_grid_tables         -- ^ Grid tables (pandoc, reST)

    | Ext_hard_line_breaks    -- ^ All newlines become hard line breaks

    | Ext_header_attributes   -- ^ Explicit header attributes {#id .class k=v}

    | Ext_ignore_line_breaks  -- ^ Newlines in paragraphs are ignored

    | Ext_implicit_figures    -- ^ A paragraph with just an image is a figure

    | Ext_implicit_header_references -- ^ Implicit reference links for headers

    | Ext_inline_code_attributes  -- ^ Allow attributes on inline code

    | Ext_inline_notes        -- ^ Pandoc-style inline notes

    | Ext_intraword_underscores  -- ^ Treat underscore inside word as literal

    | Ext_latex_macros        -- ^ Parse LaTeX macro definitions (for math only)

    | Ext_line_blocks         -- ^ RST style line blocks

    | Ext_link_attributes         -- ^ link and image attributes

    | Ext_lists_without_preceding_blankline -- ^ Allow lists without preceding blank

    | Ext_literate_haskell    -- ^ Enable literate Haskell conventions

    | Ext_markdown_attribute      -- ^ Interpret text inside HTML as markdown iff

                                  --   container has attribute 'markdown'

    | Ext_markdown_in_html_blocks -- ^ Interpret as markdown inside HTML blocks

    | Ext_mmd_header_identifiers -- ^ Multimarkdown style header identifiers [myid]

    | Ext_mmd_link_attributes     -- ^ MMD style reference link attributes

    | Ext_mmd_title_block     -- ^ Multimarkdown metadata block

    | Ext_multiline_tables    -- ^ Pandoc-style multiline tables

    | Ext_native_divs             -- ^ Use Div blocks for contents of 
 tags

    | Ext_native_spans            -- ^ Use Span inlines for contents of 

    | Ext_old_dashes          -- ^ -- = em, - before number = en

    | Ext_pandoc_title_block  -- ^ Pandoc title block

    | Ext_pipe_tables         -- ^ Pipe tables (as in PHP markdown extra)

    | Ext_raw_attribute           -- ^ Allow explicit raw blocks/inlines

    | Ext_raw_html            -- ^ Allow raw HTML

    | Ext_raw_tex             -- ^ Allow raw TeX (other than math)

    | Ext_shortcut_reference_links -- ^ Shortcut reference links

    | Ext_simple_tables       -- ^ Pandoc-style simple tables

    | Ext_smart               -- ^ "Smart" quotes, apostrophes, ellipses, dashes

    | Ext_space_in_atx_header -- ^ Require space between # and header text

    | Ext_spaced_reference_links -- ^ Allow space between two parts of ref link

    | Ext_startnum            -- ^ Make start number of ordered list significant

    | Ext_strikeout           -- ^ Strikeout using ~~this~~ syntax

    | Ext_subscript           -- ^ Subscript using ~this~ syntax

    | Ext_superscript         -- ^ Superscript using ^this^ syntax

    | Ext_table_captions      -- ^ Pandoc-style table captions

    | Ext_tex_math_dollars    -- ^ TeX math between $..$ or $$..$$

    | Ext_tex_math_double_backslash  -- ^ TeX math btw \\(..\\) \\[..\\]

    | Ext_tex_math_single_backslash  -- ^ TeX math btw \(..\) \[..\]

    | Ext_yaml_metadata_block -- ^ YAML metadata block

    deriving (Show, Read, Enum, Eq, Ord, Bounded, Data, Typeable, Generic)

-- | Extensions to be used with pandoc-flavored markdown.

pandocExtensions :: Extensions

pandocExtensions = extensionsFromList

  [ Ext_footnotes

  , Ext_inline_notes

  , Ext_pandoc_title_block

  , Ext_yaml_metadata_block

  , Ext_table_captions

  , Ext_implicit_figures

  , Ext_simple_tables

  , Ext_multiline_tables

  , Ext_grid_tables

  , Ext_pipe_tables

  , Ext_citations

  , Ext_raw_tex

  , Ext_raw_html

  , Ext_tex_math_dollars

  , Ext_latex_macros

  , Ext_fenced_code_blocks

  , Ext_fenced_code_attributes

  , Ext_backtick_code_blocks

  , Ext_inline_code_attributes

  , Ext_raw_attribute

  , Ext_markdown_in_html_blocks

  , Ext_native_divs

  , Ext_fenced_divs

  , Ext_native_spans

  , Ext_bracketed_spans

  , Ext_escaped_line_breaks

  , Ext_fancy_lists

  , Ext_startnum

  , Ext_definition_lists

  , Ext_example_lists

  , Ext_all_symbols_escapable

  , Ext_intraword_underscores

  , Ext_blank_before_blockquote

  , Ext_blank_before_header

  , Ext_space_in_atx_header

  , Ext_strikeout

  , Ext_superscript

  , Ext_subscript

  , Ext_auto_identifiers

  , Ext_header_attributes

  , Ext_link_attributes

  , Ext_implicit_header_references

  , Ext_line_blocks

  , Ext_shortcut_reference_links

  , Ext_smart

  ]

-- | Extensions to be used with plain text output.

plainExtensions :: Extensions

plainExtensions = extensionsFromList

  [ Ext_table_captions

  , Ext_implicit_figures

  , Ext_simple_tables

  , Ext_multiline_tables

  , Ext_grid_tables

  , Ext_latex_macros

  , Ext_fancy_lists

  , Ext_startnum

  , Ext_definition_lists

  , Ext_example_lists

  , Ext_intraword_underscores

  , Ext_blank_before_blockquote

  , Ext_blank_before_header

  , Ext_strikeout

  ]

-- | Extensions to be used with github-flavored markdown.

phpMarkdownExtraExtensions :: Extensions

phpMarkdownExtraExtensions = extensionsFromList

  [ Ext_footnotes

  , Ext_pipe_tables

  , Ext_raw_html

  , Ext_markdown_attribute

  , Ext_fenced_code_blocks

  , Ext_definition_lists

  , Ext_intraword_underscores

  , Ext_header_attributes

  , Ext_link_attributes

  , Ext_abbreviations

  , Ext_shortcut_reference_links

  , Ext_spaced_reference_links

  ]

-- | Extensions to be used with github-flavored markdown.

githubMarkdownExtensions :: Extensions

githubMarkdownExtensions = extensionsFromList

  [ Ext_angle_brackets_escapable

  , Ext_pipe_tables

  , Ext_raw_html

  , Ext_fenced_code_blocks

  , Ext_gfm_auto_identifiers

  , Ext_ascii_identifiers

  , Ext_backtick_code_blocks

  , Ext_autolink_bare_uris

  , Ext_space_in_atx_header

  , Ext_intraword_underscores

  , Ext_strikeout

  , Ext_emoji

  , Ext_lists_without_preceding_blankline

  , Ext_shortcut_reference_links

  ]

-- | Extensions to be used with multimarkdown.

multimarkdownExtensions :: Extensions

multimarkdownExtensions = extensionsFromList

  [ Ext_pipe_tables

  , Ext_raw_html

  , Ext_markdown_attribute

  , Ext_mmd_link_attributes

  -- , Ext_raw_tex

  -- Note: MMD's raw TeX syntax requires raw TeX to be

  -- enclosed in HTML comment

  , Ext_tex_math_double_backslash

  , Ext_intraword_underscores

  , Ext_mmd_title_block

  , Ext_footnotes

  , Ext_definition_lists

  , Ext_all_symbols_escapable

  , Ext_implicit_header_references

  , Ext_shortcut_reference_links

  , Ext_auto_identifiers

  , Ext_mmd_header_identifiers

  , Ext_implicit_figures

  -- Note: MMD's syntax for superscripts and subscripts

  -- is a bit more permissive than pandoc's, allowing

  -- e^2 and a~1 instead of e^2^ and a~1~, so even with

  -- these options we don't have full support for MMD

  -- superscripts and subscripts, but there's no reason

  -- not to include these:

  , Ext_superscript

  , Ext_subscript

  , Ext_backtick_code_blocks

  , Ext_spaced_reference_links

  -- So far only in dev version of mmd:

  , Ext_raw_attribute

  ]

-- | Language extensions to be used with strict markdown.

strictExtensions :: Extensions

strictExtensions = extensionsFromList

  [ Ext_raw_html

  , Ext_shortcut_reference_links

  , Ext_spaced_reference_links

  ]

-- | Default extensions from format-describing string.

getDefaultExtensions :: String -> Extensions

getDefaultExtensions "markdown_strict" = strictExtensions

getDefaultExtensions "markdown_phpextra" = phpMarkdownExtraExtensions

getDefaultExtensions "markdown_mmd" = multimarkdownExtensions

getDefaultExtensions "markdown_github" = githubMarkdownExtensions

getDefaultExtensions "markdown"        = pandocExtensions

getDefaultExtensions "muse"            = extensionsFromList

                                           [Ext_amuse,

                                            Ext_auto_identifiers]

getDefaultExtensions "plain"           = plainExtensions

getDefaultExtensions "gfm"             = githubMarkdownExtensions

getDefaultExtensions "org"             = extensionsFromList

                                          [Ext_citations,

                                           Ext_auto_identifiers]

getDefaultExtensions "html"            = extensionsFromList

                                          [Ext_auto_identifiers,

                                           Ext_native_divs,

                                           Ext_line_blocks,

                                           Ext_native_spans]

getDefaultExtensions "html4"           = getDefaultExtensions "html"

getDefaultExtensions "html5"           = getDefaultExtensions "html"

getDefaultExtensions "epub"            = extensionsFromList

                                          [Ext_raw_html,

                                           Ext_native_divs,

                                           Ext_native_spans,

                                           Ext_epub_html_exts]

getDefaultExtensions "epub2"           = getDefaultExtensions "epub"

getDefaultExtensions "epub3"           = getDefaultExtensions "epub"

getDefaultExtensions "latex"           = extensionsFromList

                                          [Ext_smart,

                                           Ext_latex_macros,

                                           Ext_auto_identifiers]

getDefaultExtensions "context"         = extensionsFromList

                                          [Ext_smart,

                                           Ext_auto_identifiers]

getDefaultExtensions "textile"         = extensionsFromList

                                          [Ext_old_dashes,

                                           Ext_smart,

                                           Ext_raw_html,

                                           Ext_auto_identifiers]

getDefaultExtensions "opml"            = pandocExtensions -- affects notes

getDefaultExtensions _                 = extensionsFromList

                                          [Ext_auto_identifiers]

-- | Parse a format-specifying string into a markup format and a function that

-- takes Extensions and enables and disables extensions as defined in the format

-- spec.

parseFormatSpec :: String

                -> Either ParseError (String, Extensions -> Extensions)

parseFormatSpec = parse formatSpec ""

  where formatSpec = do

          name <- formatName

          extMods <- many extMod

          return (name, \x -> foldl (flip ($)) x extMods)

        formatName = many1 $ noneOf "-+"

        extMod = do

          polarity <- oneOf "-+"

          name <- many $ noneOf "-+"

          ext <- case safeRead ("Ext_" ++ name) of

                       Just n  -> return n

                       Nothing

                         | name == "lhs" -> return Ext_literate_haskell

                         | otherwise -> fail $ "Unknown extension: " ++ name

          return $ case polarity of

                        '-' -> disableExtension ext

                        _   -> enableExtension ext

$(deriveJSON defaultOptions ''Extension)