From 58e712b4ec8b8c5fe49b86dfbbfa640e1ce0dfb8 Mon Sep 17 00:00:00 2001 From: Florian Fischer Date: Fri, 1 Nov 2024 13:05:10 +0100 Subject: vis: add slides lexer for my pandoc beamer presentations --- config/vis/lexers/slides.lua | 101 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 config/vis/lexers/slides.lua (limited to 'config/vis/lexers') diff --git a/config/vis/lexers/slides.lua b/config/vis/lexers/slides.lua new file mode 100644 index 0000000..98769cc --- /dev/null +++ b/config/vis/lexers/slides.lua @@ -0,0 +1,101 @@ +-- Copyright 2006-2024 Mitchell. See LICENSE. +-- Markdown LPeg lexer. + +local lexer = lexer +local P, S, B = lpeg.P, lpeg.S, lpeg.B + +local lex = lexer.new(..., {no_user_word_lists = true}) + +-- Distinguish between horizontal and vertical space so html start rule has a chance to match. +lex:modify_rule('whitespace', lex:tag(lexer.WHITESPACE, S(' \t')^1 + S('\r\n')^1)) + +-- Block elements. +local function h(n) + return lex:tag(string.format('%s.h%s', lexer.HEADING, 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)) + +lex:add_rule('hr', + lex:tag('hr', lpeg.Cmt(lexer.starts_line(lpeg.C(S('*-_')), true), 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 -- include \n for eolfilled styles + end))) + +lex:add_rule('list', lex:tag(lexer.LIST, + lexer.starts_line(lexer.digit^1 * '.' + S('*+-'), true) * S(' \t'))) + +local hspace = lexer.space - '\n' +local blank_line = '\n' * hspace^0 * ('\n' + P(-1)) + +local code_line = lexer.starts_line((B(' ') + B('\t')) * lexer.to_eol(), true) +local code_block = + lexer.range(lexer.starts_line('```', true), '\n```' * hspace^0 * ('\n' + P(-1))) + + lexer.range(lexer.starts_line('~~~', true), '\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', lex:tag(lexer.CODE, code_line + code_block + code_inline)) + +lex:add_rule('blockquote', + lex:tag(lexer.STRING, lpeg.Cmt(lexer.starts_line('>', true), function(input, index) + local _, e = input:find('\n[ \t]*\r?\n', index) -- the next blank line (possibly with indentation) + return (e or #input) + 1 + end))) + +-- Span elements. +lex:add_rule('escape', lex:tag(lexer.DEFAULT, P('\\') * 1)) + +local link_text = lexer.range('[', ']', true) +local link_target = + '(' * (lexer.any - S(') \t'))^0 * (S(' \t')^1 * lexer.range('"', false, false))^-1 * ')' +local link_url = 'http' * P('s')^-1 * '://' * (lexer.any - lexer.space)^1 + + ('<' * lexer.alpha^2 * ':' * (lexer.any - lexer.space - '>')^1 * '>') +lex:add_rule('link', lex:tag(lexer.LINK, P('!')^-1 * link_text * link_target + link_url)) + +local link_ref = lex:tag(lexer.REFERENCE, link_text * S(' \t')^0 * lexer.range('[', ']', true)) +local ref_link_label = lex:tag(lexer.REFERENCE, lexer.range('[', ']', true) * ':') +local ws = lex:get_rule('whitespace') +local ref_link_url = lex:tag(lexer.LINK, (lexer.any - lexer.space)^1) +local ref_link_title = lex:tag(lexer.STRING, lexer.range('"', true, false) + + lexer.range("'", true, false) + lexer.range('(', ')', true)) +lex:add_rule('link_ref', link_ref + ref_link_label * ws * ref_link_url * (ws * ref_link_title)^-1) + +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 = B(punct_space - s) * s * #fl_char + s * #(fl_char - lexer.punct) + local right_fl = B(lexer.punct) * s * #(punct_space - s) + 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 = (B(punct_space) + #lexer.starts_line('_')) * flanked_range('__', true) * + #(punct_space + -1) +lex:add_rule('strong', lex:tag(lexer.BOLD, asterisk_strong + underscore_strong)) + +local asterisk_em = flanked_range('*') +local underscore_em = (B(punct_space) + #lexer.starts_line('_')) * flanked_range('_', true) * + #(punct_space + -1) +lex:add_rule('em', lex:tag(lexer.ITALIC, asterisk_em + underscore_em)) + +-- Embedded LaTeX. +local latex = lexer.load('latex') +local latex_start_rule = lexer.starts_line(P(' ')^-3) * #P('\\') * latex:get_rule('environment') -- P(' ')^4 starts code_line +local latex_end_rule = #blank_line * ws +lex:embed(latex, latex_start_rule, latex_end_rule) + +-- Embedded yaml. +local yaml = lexer.load('yaml') +local yaml_start_rule = #lexer.starts_line('---') * ws +local yaml_end_rule = #lexer.starts_line('---') * ws +lex:embed(yaml, yaml_start_rule, yaml_end_rule) + +return lex -- cgit v1.2.3