lexlua: Added txt2tags lexer.

Thanks to Julien L.

1 files changed, 196 insertions, 0 deletions

diff --git a/lexlua/txt2tags.lua b/lexlua/txt2tags.lua
new file mode 100644
index 000000000..828b8b8fe
--- /dev/null
+++ b/lexlua/txt2tags.lua
@@ -0,0 +1,196 @@
+-- txt2tags LPeg lexer.
+-- (developed and tested with Txt2tags Markup Rules
+-- [https://txt2tags.org/doc/english/rules.t2t])
+-- Contributed by Julien L.
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+local nonspace = lexer.any - lexer.space
+
+local lex = lexer.new('txt2tags')
+
+-- Whitespace.
+local ws = token(lexer.WHITESPACE, (lexer.space - lexer.newline)^1)
+
+-- Titles
+local alphanumeric = R('AZ') + R('az') + R('09') + P('_') + P('-')
+local header_label = token('header_label_start', '[') *
+                     token('header_label', alphanumeric^1) *
+                     token('header_label_end', ']')
+local header = (token('h5', ('=====' * (lexer.nonnewline - '=')^1 * '=====') +
+                            ('+++++' * (lexer.nonnewline - '+')^1 * '+++++')) *
+                header_label^-1) +
+               (token('h4', ('====' * (lexer.nonnewline - '=')^1 * '====') +
+                            ('++++' * (lexer.nonnewline - '+')^1 * '++++')) *
+                header_label^-1) +
+               (token('h3', ('===' * (lexer.nonnewline - '=')^1 * '===') +
+                            ('+++' * (lexer.nonnewline - '+')^1 * '+++')) *
+                header_label^-1) +
+               (token('h2', ('==' * (lexer.nonnewline - '=')^1 * '==') +
+                            ('++' * (lexer.nonnewline - '+')^1 * '++')) *
+                header_label^-1) +
+               (token('h1', ('=' * (lexer.nonnewline - '=')^1 * '=') +
+                            ('+' * (lexer.nonnewline - '+')^1 * '+')) *
+                header_label^-1)
+
+-- Comments.
+local line_comment = lexer.starts_line('%') * lexer.nonnewline^0
+local block_comment = lexer.starts_line('%%%') *
+                      (lexer.space - lexer.newline)^0 * lexer.newline *
+                      (lexer.any - '%%%')^0 * lexer.starts_line('%%%')^-1
+local comment = token(lexer.COMMENT, block_comment + line_comment)
+
+-- Inline.
+local bold = token('bold', ('**' * nonspace * '**' * S('*')^0) +
+                           ('**' * nonspace *
+                            (lexer.nonnewline - (nonspace * '**'))^0 *
+                            nonspace * '**' * S('*')^0))
+local italic = token('italic', ('//' * nonspace * '//' * S('/')^0) +
+                               ('//' * nonspace *
+                                (lexer.nonnewline - (nonspace * '//'))^0 *
+                                nonspace * '//' * S('/')^0))
+local underline = token('underline', ('__' * nonspace * '__' * S('_')^0) +
+                                     ('__' * nonspace *
+                                      (lexer.nonnewline - (nonspace * '__'))^0 *
+                                      nonspace * '__' * S('_')^0))
+local strike = token('strike', ('--' * nonspace * '--' * S('-')^0) +
+                               ('--' * nonspace *
+                                (lexer.nonnewline - (nonspace * '--'))^0 *
+                                nonspace * '--' * S('-')^0))
+local mono = token('mono', ('``' * nonspace * '``' * S('`')^0) +
+                           ('``' * nonspace *
+                            (lexer.nonnewline - (nonspace * '``'))^0 *
+                            nonspace * '``' * S('`')^0))
+local raw = token('raw', ('""' * nonspace * '""' * S('"')^0) +
+                         ('""' * nonspace *
+                          (lexer.nonnewline - (nonspace * '""'))^0 * nonspace *
+                          '""' * S('"')^0))
+local tagged = token('tagged', ('\'\'' * nonspace * '\'\'' * S('\'')^0) +
+                               ('\'\'' * nonspace *
+                                (lexer.nonnewline - (nonspace * '\'\''))^0 *
+                                nonspace * '\'\'' * S('\'')^0))
+local inline = bold + italic + underline + strike + mono + raw + tagged
+
+-- Link.
+local email = token('email', (nonspace - '@')^1 * '@' * (nonspace - '.')^1 *
+                             ('.' * (nonspace - '.' - '?')^1)^1 *
+                             ('?' * nonspace^1)^-1)
+local host = token('host', (P('www') + P('WWW') + P('ftp') + P('FTP')) *
+                           (nonspace - '.')^0 * '.' * (nonspace - '.')^1 * '.' *
+                           (nonspace - ',' - '.')^1)
+local url = token('url', (nonspace - '://')^1 * '://' *
+                         (nonspace - ',' - '.')^1 *
+                         ('.' * (nonspace - ',' - '.' - '/' - '?' - '#')^1)^1 *
+                         ('/' * (nonspace - '.' - '/' - '?' - '#')^0 *
+                          ('.' * (nonspace - ',' - '.' - '?' - '#')^1)^0)^0 *
+                         ('?' * (nonspace - '#')^1)^-1 * ('#' * nonspace^0)^-1)
+local label_with_address = token('label_start', '[') *
+                           lexer.space^0 *
+                           token('address_label', ((nonspace - ']')^1 *
+                                                   lexer.space^1)^1) *
+                           token('address', (nonspace - ']')^1) *
+                           token('label_end', ']')
+local link = label_with_address + url + host + email
+
+-- Line.
+local line = token('line', (P('-') + P('=') + P('_'))^20)
+
+-- Image.
+local image_only = token('image_start', '[') *
+                   token('image', (nonspace - ']')^1) * token('image_end', ']')
+local image_link = token('image_link_start', '[') * image_only *
+                   token('image_link_sep', lexer.space^1) *
+                   token('image_link', (nonspace - ']')^1) *
+                   token('image_link_end', ']')
+local image = image_link + image_only
+
+-- Macro.
+local macro = token('macro', '%%' * (nonspace - '(')^1 *
+                             ('(' * (lexer.nonnewline - ')')^0 * ')')^-1)
+
+-- Verbatim.
+local verbatim_line = lexer.starts_line('```') * (lexer.space - lexer.newline) *
+                      lexer.nonnewline^0
+local verbatim_block = lexer.starts_line('```') *
+                       (lexer.space - lexer.newline)^0 * lexer.newline *
+                       (lexer.any - '```')^0 * lexer.starts_line('```')^-1
+local verbatim_area = token('verbatim_area', verbatim_block + verbatim_line)
+
+-- Raw.
+local raw_line = lexer.starts_line('"""') * (lexer.space - lexer.newline) *
+                 lexer.nonnewline^0
+local raw_block = lexer.starts_line('"""') * (lexer.space - lexer.newline)^0 *
+                  lexer.newline * (lexer.any - '"""')^0 *
+                  lexer.starts_line('"""')^-1
+local raw_area = token('raw_area', raw_block + raw_line)
+
+-- Tagged.
+local tagged_line = lexer.starts_line('\'\'\'') *
+                    (lexer.space - lexer.newline) * lexer.nonnewline^0
+local tagged_block = lexer.starts_line('\'\'\'') *
+                     (lexer.space - lexer.newline)^0 * lexer.newline *
+                     (lexer.any - '\'\'\'')^0 * lexer.starts_line('\'\'\'')^-1
+local tagged_area = token('tagged_area', tagged_block + tagged_line)
+
+-- Table.
+local table_sep = token('table_sep', '|')
+local cell_content = inline + link + image + macro +
+                     token('cell_content', lexer.nonnewline - ' |')
+local header_cell_content = token('header_cell_content',
+                                  lexer.nonnewline - ' |')
+local field_sep = ' ' * table_sep^1 * ' '
+local table_row_end = P(' ')^0 * table_sep^0
+local table_row = lexer.starts_line(P(' ')^0 * table_sep) * cell_content^0 *
+                  (field_sep * cell_content^0)^0 * table_row_end
+local table_row_header = lexer.starts_line(P(' ')^0 * table_sep * table_sep) *
+                         header_cell_content^0 *
+                         (field_sep * header_cell_content^0)^0 * table_row_end
+local table = table_row_header + table_row
+
+lex:add_rule('table', table)
+lex:add_rule('link', link)
+lex:add_rule('line', line)
+lex:add_rule('header', header)
+lex:add_rule('comment', comment)
+lex:add_rule('whitespace', ws)
+lex:add_rule('image', image)
+lex:add_rule('macro', macro)
+lex:add_rule('inline', inline)
+lex:add_rule('verbatim_area', verbatim_area)
+lex:add_rule('raw_area', raw_area)
+lex:add_rule('tagged_area', tagged_area)
+
+local font_size = lexer.property_int['fontsize'] > 0 and
+                  lexer.property_int['fontsize'] or 10
+local hstyle = 'fore:$(color.red)'
+
+lex:add_style('line', 'bold')
+lex:add_style('h5', hstyle..',size:'..(font_size + 1))
+lex:add_style('h4', hstyle..',size:'..(font_size + 2))
+lex:add_style('h3', hstyle..',size:'..(font_size + 3))
+lex:add_style('h2', hstyle..',size:'..(font_size + 4))
+lex:add_style('h1', hstyle..',size:'..(font_size + 5))
+lex:add_style('header_label', lexer.STYLE_LABEL)
+lex:add_style('email', 'underlined')
+lex:add_style('host', 'underlined')
+lex:add_style('url', 'underlined')
+lex:add_style('address_label', lexer.STYLE_LABEL)
+lex:add_style('address', 'underlined')
+lex:add_style('image', 'fore:$(color.green)')
+lex:add_style('image_link', 'underlined')
+lex:add_style('macro', lexer.STYLE_PREPROCESSOR)
+lex:add_style('bold', 'bold')
+lex:add_style('italic', 'italics')
+lex:add_style('underline', 'underlined')
+lex:add_style('strike', 'italics') -- a strike style is not available
+lex:add_style('mono', 'font:mono')
+lex:add_style('raw', 'back:$(color.grey)')
+lex:add_style('tagged', lexer.STYLE_EMBEDDED)
+lex:add_style('verbatim_area', 'font:mono') -- in consistency with mono
+lex:add_style('raw_area', 'back:$(color.grey)') -- in consistency with raw
+lex:add_style('tagged_area', lexer.STYLE_EMBEDDED) -- in consistency with tagged
+lex:add_style('table_sep', 'fore:$(color.green)')
+lex:add_style('header_cell_content', 'fore:$(color.green)')
+
+return lex