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-rw-r--r--lua/lexers/markdown.lua193
1 files changed, 94 insertions, 99 deletions
diff --git a/lua/lexers/markdown.lua b/lua/lexers/markdown.lua
index fe57a1b..cbd4ba2 100644
--- a/lua/lexers/markdown.lua
+++ b/lua/lexers/markdown.lua
@@ -1,109 +1,104 @@
--- Copyright 2006-2017 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- Copyright 2006-2022 Mitchell. See LICENSE.
-- Markdown LPeg lexer.
-local l = require('lexer')
-local token, word_match = l.token, l.word_match
-local P, R, S = lpeg.P, lpeg.R, lpeg.S
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, S = lpeg.P, lpeg.S
-local M = {_NAME = 'markdown'}
-
--- Whitespace.
-local ws = token(l.WHITESPACE, S(' \t')^1 + S('\v\r\n')^1)
+local lex = lexer.new('markdown')
-- Block elements.
-local header = token('h6', l.starts_line('######') * l.nonnewline^0) +
- token('h5', l.starts_line('#####') * l.nonnewline^0) +
- token('h4', l.starts_line('####') * l.nonnewline^0) +
- token('h3', l.starts_line('###') * l.nonnewline^0) +
- token('h2', l.starts_line('##') * l.nonnewline^0) +
- token('h1', l.starts_line('#') * l.nonnewline^0)
-
-local blockquote = token(l.STRING,
- lpeg.Cmt(l.starts_line(S(' \t')^0 * '>'),
- function(input, index)
- local _, e = input:find('\n[ \t]*\r?\n',
- index)
- return (e or #input) + 1
- end))
-
-local blockcode = token('code', l.starts_line(P(' ')^4 + P('\t')) * -P('<') *
- l.nonnewline^0)
-
-local hr = token('hr', lpeg.Cmt(l.starts_line(S(' \t')^0 * lpeg.C(S('*-_'))),
- function(input, index, c)
- local line = input:match('[^\n]*', index)
- line = line:gsub('[ \t]', '')
- if line:find('[^'..c..']') or #line < 2 then
- return nil
- end
- return (input:find('\n', index) or #input) + 1
- end))
+local function h(n) return token('h' .. n, lexer.to_eol(lexer.starts_line(string.rep('#', n)))) end
+lex:add_rule('header', h(6) + h(5) + h(4) + h(3) + h(2) + h(1))
+local font_size = tonumber(lexer.property_expanded['style.default']:match('size:(%d+)')) or 10
+local function add_header_style(n)
+ lex:add_style('h' .. n, {fore = lexer.colors.red, size = (font_size + (6 - n))})
+end
+for i = 1, 6 do add_header_style(i) end
+
+lex:add_rule('blockquote',
+ token(lexer.STRING, lpeg.Cmt(lexer.starts_line(S(' \t')^0 * '>'), function(input, index)
+ local _, e = input:find('\n[ \t]*\r?\n', index)
+ return (e or #input) + 1
+ end)))
+
+lex:add_rule('list', token('list',
+ lexer.starts_line(S(' \t')^0 * (S('*+-') + lexer.digit^1 * '.')) * S(' \t')))
+lex:add_style('list', lexer.styles.constant)
+
+local hspace = S('\t\v\f\r ')
+local blank_line = '\n' * hspace^0 * ('\n' + P(-1))
+
+local code_line = lexer.to_eol(lexer.starts_line(P(' ')^4 + '\t') * -P('<')) * lexer.newline^-1
+local code_block = lexer.range(lexer.starts_line('```'), '\n```' * hspace^0 * ('\n' + P(-1)))
+local code_inline = lpeg.Cmt(lpeg.C(P('`')^1), function(input, index, bt)
+ -- `foo`, ``foo``, ``foo`bar``, `foo``bar` are all allowed.
+ local _, e = input:find('[^`]' .. bt .. '%f[^`]', index)
+ return (e or #input) + 1
+end)
+lex:add_rule('block_code', token('code', code_line + code_block + code_inline))
+lex:add_style('code', lexer.styles.embedded .. {eolfilled = true})
+
+lex:add_rule('hr',
+ token('hr', lpeg.Cmt(lexer.starts_line(S(' \t')^0 * lpeg.C(S('*-_'))), function(input, index, c)
+ local line = input:match('[^\r\n]*', index):gsub('[ \t]', '')
+ if line:find('[^' .. c .. ']') or #line < 2 then return nil end
+ return (select(2, input:find('\r?\n', index)) or #input) + 1
+ end)))
+lex:add_style('hr', {back = lexer.colors.black, eolfilled = true})
+
+-- Whitespace.
+local ws = token(lexer.WHITESPACE, S(' \t')^1 + S('\v\r\n')^1)
+lex:add_rule('whitespace', ws)
-- Span elements.
-local dq_str = token(l.STRING, l.delimited_range('"', false, true))
-local sq_str = token(l.STRING, l.delimited_range("'", false, true))
-local paren_str = token(l.STRING, l.delimited_range('()'))
-local link = token('link', P('!')^-1 * l.delimited_range('[]') *
- (P('(') * (l.any - S(') \t'))^0 *
- (S(' \t')^1 *
- l.delimited_range('"', false, true))^-1 * ')' +
- S(' \t')^0 * l.delimited_range('[]')) +
- P('http://') * (l.any - l.space)^1)
-local link_label = token('link_label', l.delimited_range('[]') * ':') * ws *
- token('link_url', (l.any - l.space)^1) *
- (ws * (dq_str + sq_str + paren_str))^-1
-
-local strong = token('strong', (P('**') * (l.any - '**')^0 * P('**')^-1) +
- (P('__') * (l.any - '__')^0 * P('__')^-1))
-local em = token('em',
- l.delimited_range('*', true) + l.delimited_range('_', true))
-local code = token('code', (P('``') * (l.any - '``')^0 * P('``')^-1) +
- l.delimited_range('`', true, true))
-
-local escape = token(l.DEFAULT, P('\\') * 1)
-
-local list = token('list',
- l.starts_line(S(' \t')^0 * (S('*+-') + R('09')^1 * '.')) *
- S(' \t'))
-
-M._rules = {
- {'header', header},
- {'list', list},
- {'blockquote', blockquote},
- {'blockcode', blockcode},
- {'hr', hr},
- {'whitespace', ws},
- {'link_label', link_label},
- {'escape', escape},
- {'link', link},
- {'strong', strong},
- {'em', em},
- {'code', code},
-}
-
-local font_size = 10
-local hstyle = 'fore:red'
-M._tokenstyles = {
- h6 = hstyle,
- h5 = hstyle..',size:'..(font_size + 1),
- h4 = hstyle..',size:'..(font_size + 2),
- h3 = hstyle..',size:'..(font_size + 3),
- h2 = hstyle..',size:'..(font_size + 4),
- h1 = hstyle..',size:'..(font_size + 5),
- code = l.STYLE_EMBEDDED..',eolfilled',
- hr = l.STYLE_DEFAULT..',bold',
- link = 'underlined',
- link_url = 'underlined',
- link_label = l.STYLE_LABEL,
- strong = 'bold',
- em = 'italics',
- list = l.STYLE_CONSTANT,
-}
+lex:add_rule('escape', token(lexer.DEFAULT, P('\\') * 1))
+
+local ref_link_label = token('link_label', lexer.range('[', ']', true) * ':')
+local ref_link_url = token('link_url', (lexer.any - lexer.space)^1)
+local ref_link_title = token(lexer.STRING, lexer.range('"', true, false) +
+ lexer.range("'", true, false) + lexer.range('(', ')', true))
+lex:add_rule('link_label', ref_link_label * ws * ref_link_url * (ws * ref_link_title)^-1)
+lex:add_style('link_label', lexer.styles.label)
+lex:add_style('link_url', {underlined = true})
+
+local link_label = P('!')^-1 * lexer.range('[', ']', true)
+local link_target =
+ '(' * (lexer.any - S(') \t'))^0 * (S(' \t')^1 * lexer.range('"', false, false))^-1 * ')'
+local link_ref = S(' \t')^0 * lexer.range('[', ']', true)
+local link_url = 'http' * P('s')^-1 * '://' * (lexer.any - lexer.space)^1 +
+ ('<' * lexer.alpha^2 * ':' * (lexer.any - lexer.space - '>')^1 * '>')
+lex:add_rule('link', token('link', link_label * (link_target + link_ref) + link_url))
+lex:add_style('link', {underlined = true})
+
+local punct_space = lexer.punct + lexer.space
+
+-- Handles flanking delimiters as described in
+-- https://github.github.com/gfm/#emphasis-and-strong-emphasis in the cases where simple
+-- delimited ranges are not sufficient.
+local function flanked_range(s, not_inword)
+ local fl_char = lexer.any - s - lexer.space
+ local left_fl = lpeg.B(punct_space - s) * s * #fl_char + s * #(fl_char - lexer.punct)
+ local right_fl = lpeg.B(lexer.punct) * s * #(punct_space - s) + lpeg.B(fl_char) * s
+ return left_fl * (lexer.any - blank_line - (not_inword and s * #punct_space or s))^0 * right_fl
+end
+
+local asterisk_strong = flanked_range('**')
+local underscore_strong = (lpeg.B(punct_space) + #lexer.starts_line('_')) *
+ flanked_range('__', true) * #(punct_space + -1)
+lex:add_rule('strong', token('strong', asterisk_strong + underscore_strong))
+lex:add_style('strong', {bold = true})
+
+local asterisk_em = flanked_range('*')
+local underscore_em = (lpeg.B(punct_space) + #lexer.starts_line('_')) * flanked_range('_', true) *
+ #(punct_space + -1)
+lex:add_rule('em', token('em', asterisk_em + underscore_em))
+lex:add_style('em', {italics = true})
-- Embedded HTML.
-local html = l.load('html')
-local start_rule = token('tag', l.starts_line(S(' \t')^0 * '<'))
-local end_rule = token(l.DEFAULT, P('\n')) -- TODO: l.WHITESPACE causes errors
-l.embed_lexer(M, html, start_rule, end_rule)
+local html = lexer.load('html')
+local start_rule = lexer.starts_line(P(' ')^-3) * #P('<') * html:get_rule('element') -- P(' ')^4 starts code_line
+local end_rule = token(lexer.DEFAULT, blank_line) -- TODO: lexer.WHITESPACE errors
+lex:embed(html, start_rule, end_rule)
-return M
+return lex
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