Move all lua related files to lua/ subfolder

Also remove the lexers sub directory from the Lua search path.
As a result we attempt to open fewer files during startup:

 $ strace -e open -o log ./vis +q config.h && wc -l log

In order to avoid having to modifiy all lexers which `require('lexer')`
we instead place a symlink in the top level directory.

 $ ./configure --disable-lua
 $ rm -rf lua

Should result in a source tree with most lua specifc functionality
removed.

1 files changed, 0 insertions, 109 deletions

diff --git a/lexers/markdown.lua b/lexers/markdown.lua
deleted file mode 100644
index 0257010..0000000
--- a/lexers/markdown.lua
+++ /dev/null
@@ -1,109 +0,0 @@
--- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. 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 M = {_NAME = 'markdown'}
-
--- Whitespace.
-local ws = token(l.WHITESPACE, l.space^1)
-
--- 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))
-
--- 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},
-  {'blockquote', blockquote},
-  {'blockcode', blockcode},
-  {'hr', hr},
-  {'list', list},
-  {'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,
-}
-
--- 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)
-
-return M