1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
=> |%
++ ln
|%
::
:: Url: optionally enclosed in triangle brackets
:: A link destination consists of either
:: - a sequence of zero or more characters between an opening < and a closing > that
:: contains no line breaks or unescaped < or > characters, or
:: - a nonempty sequence of characters that does not start with <, does not include
:: ASCII space or control characters, and includes parentheses only if (a) they are
:: backslash-escaped or (b) they are part of a balanced pair of unescaped parentheses.
:: (Implementations may impose limits on parentheses nesting to avoid performance
:: issues, but at least three levels of nesting should be supported.)
+$ url [text=@t has-triangle-brackets=?]
::
:: Url with optional title-text
+$ urlt [=url title-text=(unit @t)]
::
:: Link target: the part of a link after the display text. can be direct or reference
:: A reference link is in square brackets, and refers to a named link elsewhere.
:: - full => [Display][foo]
:: - collapsed => [Display][]
:: - shortcut => [Display]
:: Collapsed and shortcut links have a `label` equal to the display text.
+$ target $% [%direct =urlt]
[%ref type=?(%full %collapsed %shortcut) label=@t]
==
--
--
::
|%
::
:: Markdown document or fragment: a list of nodes
++ markdown =< $+ markdown
(list node)
|%
+$ node $+ markdown-node
$@ ~ :: `$@ ~` is magic that makes recursive structures work
$% [%leaf node:leaf]
[%container node:container]
==
--
::
++ inline
|%
:: A single inline element
++ element $+ inline-element
$@ ~
$%(escape entity code hardbrk softbrk text emphasis strong link image autolink html)
::
:: Any amount of elements
++ contents (list element)
::
:: -----------------------
:: List of inline elements
:: -----------------------
::
:: Backslash-escaped character
+$ escape [%escape char=@t]
::
:: HTML-entity
+$ entity [%entity code=@t]
::
:: Code span (inline code). Interpreted literally, cannot have nested elements.
:: Can be enclosed by any amount of backticks on each side, >= 1. Must be balanced.
+$ code [%code-span num-backticks=@ text=@t]
::
:: Line break
+$ hardbrk [%line-break ~]
::
:: Soft line break: a newline in the source code, will be rendered as a single space
+$ softbrk [%soft-line-break ~]
::
:: Text: Just text
+$ text [%text text=@t]
::
:: Emphasis and strong emphasis
:: Can use either tar "*" or cab "_" as the emphasis character.
:: Can have nested inline elements.
+$ emphasis [%emphasis emphasis-char=@t =contents]
+$ strong [%strong emphasis-char=@t =contents]
::
:: Link
+$ link [%link =contents =target:ln]
::
:: Images
+$ image [%image alt-text=@t =target:ln]
::
:: Autolink: a link that's just itself, surrounded by "<...>"
+$ autolink [%autolink text=@t]
::
:: HTML
+$ html [%html text=@t]
--
::
:: Leaf nodes: non-nested (i.e., terminal) nodes
++ leaf
|%
++ node $+ leaf-node
$@ ~
$%(heading break codeblk-indent codeblk-fenced html link-ref-def table paragraph blank-line)
::
:: Heading, either setext or ATX style
+$ heading [%heading style=?(%setext %atx) level=@ =contents:inline]
::
:: Thematic break (horizontal line)
:: Consists of at least 3 repetitions of either hep '-', cab '_', or tar '*'
+$ break [%break char=@t char-count=@]
::
:: Indentation-based code block: indented 4 spaces. Can include newlines and blank lines.
+$ codeblk-indent [%indent-codeblock text=@t]
::
:: Fenced code block: begins and ends with 3+ repetitions of tic (`) or sig (~).
:: Can be indented up to 3 spaces.
+$ codeblk-fenced [%fenced-codeblock char=@t char-count=@ info-string=@t indent-level=@ text=@t]
::
:: HTML
+$ html [%html text=@t]
::
:: Link reference definition (defines a named link which can be referenced elsewhere)
+$ link-ref-def [%link-ref-definition label=@t =urlt:ln]
::
:: Paragraph
+$ paragraph [%paragraph =contents:inline]
::
:: Blank lines (not rendered, but lets user control aethetic layout of the source code)
+$ blank-line [%blank-line ~]
::
:: Table (alignments: [l]eft, [r]ight, [c]enter, [n]one)
+$ table [%table widths=(list @) head=(list contents:inline) align=(list ?(%l %c %r %n)) rows=(list (list contents:inline))]
--
::
:: Container node: can contain other nodes (either container or leaf).
++ container
|%
++ node $+ container-node
$@ ~
$%(block-quote ol ul tl)
::
:: Block quote. Can be nested.
+$ block-quote [%block-quote =markdown]
::
:: Ordered list: numbered based on first list item marker.
:: Marker char can be either dot '1. asdf' or par '1) asdf'
:: Can be indented up to 3 spaces
+$ ol [%ol indent-level=@ marker-char=@t start-num=@ contents=(list markdown)] :: is-tight=?
::
:: Unordered list: bullet point list
:: Marker char can be either hep (-), lus (+) or tar (*)
:: Can be indented up to 3 spaces
+$ ul [%ul indent-level=@ marker-char=@t contents=(list markdown)] :: is-tight=?
::
:: Task list: unordered list of tasks
:: Can be indented up to 3 spaces
+$ tl [%tl indent-level=@ marker-char=@t contents=(list [is-checked=? =markdown])] :: is-tight=?
--
--
|
