Merge: Functional api

[nit.git] / lib / markdown2 / markdown_md_rendering.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Markdown rendering of Markdown documents
module markdown_md_rendering

import markdown_rendering
import markdown_github
import markdown_wikilinks

# Markdown document renderer to Markdown
class MarkdownRenderer
        super MdRenderer

        # Markdown output under construction
        private var md: Buffer is noinit

        # Render `node` as Markdown
        redef fun render(node) do
                reset
                enter_visit(node)
                return md.write_to_string
        end

        redef fun visit(node) do node.render_md(self)

        # Reset internal state
        fun reset do
                md = new Buffer
        end

        # Current indentation level
        private var indent = 0

        # Are we currently in a blockquote?
        var in_quote = 0

        # Add a `md` string to the output
        fun add_raw(md: String) do self.md.append(md)

        # Add a blank line to the output
        fun add_line do add_raw "\n"

        # Add an indentation depending on `ident` level
        fun add_indent do
                add_raw " " * indent
        end
end

private class TextLengthVisitor
        super MdVisitor

        var length = 0

        redef fun visit(node) do node.process_len(self)
end

redef class MdNode

        # Render `self` as Markdown
        fun render_md(v: MarkdownRenderer) do visit_all(v)

        private fun process_len(v: TextLengthVisitor) do visit_all(v)
end

redef class MdDocument
        redef fun render_md(v) do
                var node = first_child
                while node != null do
                        v.enter_visit(node)
                        node = node.next
                        if node != null then
                                v.add_line
                        end
                end
        end
end

# Blocks

redef class MdBlockQuote
        redef fun render_md(v) do
                v.in_quote += 1
                var node = first_child
                while node != null do
                        v.add_indent
                        v.add_raw "> "
                        v.enter_visit(node)
                        node = node.next
                end
                v.in_quote -= 1
        end
end

redef class MdIndentedCodeBlock
        redef fun render_md(v) do
                var literal = self.literal
                if literal == null then return

                var lines = literal.split("\n")
                for i in [0..lines.length[ do
                        if i == lines.length - 1 then continue
                        var line = lines[i]
                        if line.is_empty then
                                v.add_raw "\n"
                        else
                                v.add_indent
                                if use_tabs then
                                        v.add_raw "\t"
                                else
                                        v.add_raw " " * 4
                                end
                                v.add_raw line
                                v.add_line
                        end
                end
        end
end

redef class MdFencedCodeBlock
        redef fun render_md(v) do
                var info = self.info
                v.add_indent
                v.add_raw fence_char.to_s * fence_length
                v.add_raw info or else ""
                for line in (literal or else "").split("\n") do
                        v.add_line
                        if not line.is_empty then
                                v.add_indent
                        end
                        v.add_raw line
                end
                v.add_indent
                v.add_raw fence_char.to_s * fence_length
                v.add_line
        end
end

redef class MdHeading
        redef fun render_md(v) do
                if is_setext then
                        visit_all(v)
                        var length_visitor = new TextLengthVisitor
                        length_visitor.enter_visit(self)
                        v.add_line
                        if level == 1 then
                                v.add_raw "=" * length_visitor.length
                        else
                                v.add_raw "-" * length_visitor.length
                        end
                else
                        v.add_raw "#" * level
                        v.add_raw " "
                        visit_all(v)
                        if has_atx_trailing then
                                v.add_raw " "
                                v.add_raw "#" * level
                        end
                end
                v.add_line
        end
end

redef class MdOrderedList
        # Children numbering
        private var md_numbering: Int = start_number is lazy
end

redef class MdListItem
        redef fun render_md(v) do
                var parent = self.parent
                var is_tight = parent.as(MdListBlock).is_tight

                v.add_indent
                if parent isa MdUnorderedList then
                        v.add_raw parent.bullet_marker.to_s
                        v.indent += 2
                else if parent isa MdOrderedList then
                        v.add_raw "{parent.md_numbering}{parent.delimiter.to_s}"
                        v.indent += 3
                end

                var node = first_child
                if node != null then
                        v.add_raw " "
                else
                        v.add_line
                end
                while node != null do
                        v.enter_visit(node)
                        node = node.next
                        if node != null and not is_tight then
                                v.add_line
                        end
                end

                if next != null and not is_tight then
                        v.add_line
                end

                if parent isa MdUnorderedList then
                        v.indent -= 2
                else if parent isa MdOrderedList then
                        parent.md_numbering += 1
                        v.indent -= 3
                end
        end
end

redef class MdParagraph
        redef fun render_md(v) do
                if not parent isa MdBlockQuote and not parent isa MdListItem or prev != null then
                        v.add_indent
                end
                # if parent isa MdBlockQuote then
                        # v.add_raw "> "
                        # var node = first_child
                        # while node != null do
                                # v.enter_visit(node)
                                # if node isa MdSoftLineBreak or node isa MdHardLineBreak then
                                        # v.add_raw "> "
                                # end
                                # node = node.next
                        # end
                        # v.add_line
                        # return
                # end
                visit_all(v)
                v.add_line
        end
end

redef class MdThematicBreak
        redef fun render_md(v) do
                v.add_raw original_pattern
                v.add_line
        end
end

redef class MdHtmlBlock
        redef fun render_md(v) do
                v.add_raw literal or else ""
                v.add_line
        end
end

# Inlines

redef class MdHardLineBreak
        redef fun render_md(v) do
                if has_backslash then
                        v.add_raw "\\"
                else
                        v.add_raw "  "
                end
                v.add_line
                v.add_indent
                v.add_raw "> " * v.in_quote
        end

        redef fun process_len(v) do
                super
                v.length += 1
        end
end

redef class MdSoftLineBreak
        redef fun render_md(v) do
                v.add_line
                v.add_indent
                v.add_raw "> " * v.in_quote
        end

        redef fun process_len(v) do
                super
                v.length += 1
        end
end

redef class MdCode
        redef fun render_md(v) do
                v.add_raw delimiter
                v.add_raw literal
                v.add_raw delimiter
        end

        redef fun process_len(v) do
                super
                v.length += delimiter.length
        end
end

redef class MdDelimited
        redef fun render_md(v) do
                v.add_raw delimiter
                visit_all(v)
                v.add_raw delimiter
        end

        redef fun process_len(v) do
                super
                v.length += delimiter.length * 2
        end
end

redef class MdHtmlInline
        redef fun render_md(v) do
                v.add_raw literal
        end

        redef fun process_len(v) do
                v.length += literal.length
        end
end

redef class MdLinkOrImage
        redef fun render_md(v) do
                var title = self.title
                v.add_raw "["
                visit_all(v)
                v.add_raw "]"
                v.add_raw "("
                if has_brackets then
                        v.add_raw "<"
                end
                v.add_raw destination
                if has_brackets then
                        v.add_raw ">"
                end
                if title != null and not title.is_empty then
                        v.add_raw " \""
                        v.add_raw title.replace("\"", "\\\"")
                        v.add_raw "\""
                end
                v.add_raw ")"
        end
end


redef class MdImage
        redef fun render_md(v) do
                v.add_raw "!"
                super
        end
end

redef class MdLink
        redef fun render_md(v) do
                if is_autolink then
                        v.add_raw "<"
                        v.add_raw destination
                        v.add_raw ">"
                        return
                end
                super
        end
end

redef class MdText
        redef fun render_md(v) do
                v.add_raw literal
        end

        redef fun process_len(v) do
                v.length += literal.length
        end
end

# Wikilinks

redef class MdWikilink
        redef fun render_md(v) do
                v.add_raw "[["
                var title = self.title
                if title != null then
                        v.add_raw "{title} | "
                end
                v.add_raw link
                v.add_raw "]]"
        end
end