file        = section? (heading section?)*

section     = seclines
heading     = stars keyword? priority? title? hltags? NL

secline     = !&stars text NL
seclines    = secline seclines*

stars       = ~'\*+'
keyword     = ' '? ('TODO' / 'Done')
priority    = ' '? '[' ('#' letter) ']'
title       = (notagtext &hltags) / text

hltag       = ~"[\w@#%]*"
hltags      = ':' (hltag ':')*

text        = ~"[^\n\r]*"
notagtext   = ~"[^\n\r:]*"
letter      = ~"[a-zA-Z]"

NL          = '\n\r' / '\n'
empty_line  = NL NL

affl_keywd   = (affl_keywd1 / affl_keywd2) NL
affl_keywd1  = '#+' key ':' value
affl_keywd2  = '#+' optkey '[' option ']' ':' value
affl_bkend   = '#+' 'ATTR_' backend ':' value

key         = 'CAPTION' / 'HEADER' / 'NAME' / 'PLOT' / 'RESULTS' / 'AUTHOR' / 'DATE' / 'TITLE'
optkey      = 'CAPTION' / 'HEADER'

option      = ~"[^\[\]\n\r]+"
value       = text
backend     = name

gblock      = bheader bbody bend NL
bheader     = bstart (' ' bparams)? NL
bbody       = blines
bstart      = '#+BEGIN_' name
bend        = '#+END_' name
bparams     = text
bline       = !&'#+END_' text NL
blines      = bline blines*

drawer      = dheader dbody dend NL
dheader     = ':' name ':' NL
dend        = ':END:'
dbody       = dlines
dline       = !&':END:' text NL
dlines      = dline dlines*

dblock      = dbheader dbbody dbend NL
dbheader    = '#+BEGIN:' ' ' name (' ' dbparams)? NL
dbbody      = dblines
dbend       = '#+END'
dbparams    = text
dbline      = !&'#+END' text NL
dblines     = dbline dblines*

footnote    = '[fn:' fnlabel ']' fncontents
fncontents  = (!&(stars / '[fn:') text !&empty_line NL )* NL?
fnlabel     = name

name        = ~"[\w-]+"

li          = indent bullet counterset? checkbox? litag? NL
indent      = ~"[ ]*"
bullet      = '*' / '-' / '+' / counter
counterset  = '[@' counter ']'
checkbox    = '[' ~"[ -X]" ']'
litag       = text
counter     = (letter / ~"[1-9][0-9]*") ('.' / ')')

pdrawer     = ':PROPERTIES:' pdbody dend NL
pdbody      = nodeprops?
nodeprop    = ':' nodepname '+'? ':' value NL
nodeprops   = nodeprop nodeprops*
nodepname   = ~"[^\n\r\t :]+[^\n\r\t :+]$"