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, 148 insertions, 0 deletions

diff --git a/lua/lexers/ruby.lua b/lua/lexers/ruby.lua
new file mode 100644
index 0000000..d923917
--- /dev/null
+++ b/lua/lexers/ruby.lua
@@ -0,0 +1,148 @@
+-- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- Ruby 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 = 'ruby'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local line_comment = '#' * l.nonnewline_esc^0
+local block_comment = l.starts_line('=begin') * (l.any - l.newline * '=end')^0 *
+                      (l.newline * '=end')^-1
+local comment = token(l.COMMENT, block_comment + line_comment)
+
+local delimiter_matches = {['('] = ')', ['['] = ']', ['{'] = '}'}
+local literal_delimitted = P(function(input, index)
+  local delimiter = input:sub(index, index)
+  if not delimiter:find('[%w\r\n\f\t ]') then -- only non alpha-numerics
+    local match_pos, patt
+    if delimiter_matches[delimiter] then
+      -- Handle nested delimiter/matches in strings.
+      local s, e = delimiter, delimiter_matches[delimiter]
+      patt = l.delimited_range(s..e, false, false, true)
+    else
+      patt = l.delimited_range(delimiter)
+    end
+    match_pos = lpeg.match(patt, input, index)
+    return match_pos or #input + 1
+  end
+end)
+
+-- Strings.
+local cmd_str = l.delimited_range('`')
+local lit_cmd = '%x' * literal_delimitted
+local lit_array = '%w' * literal_delimitted
+local sq_str = l.delimited_range("'")
+local dq_str = l.delimited_range('"')
+local lit_str = '%' * S('qQ')^-1 * literal_delimitted
+local heredoc = '<<' * P(function(input, index)
+  local s, e, indented, _, delimiter =
+    input:find('(%-?)(["`]?)([%a_][%w_]*)%2[\n\r\f;]+', index)
+  if s == index and delimiter then
+    local end_heredoc = (#indented > 0 and '[\n\r\f]+ *' or '[\n\r\f]+')
+    local _, e = input:find(end_heredoc..delimiter, e)
+    return e and e + 1 or #input + 1
+  end
+end)
+-- TODO: regex_str fails with `obj.method /patt/` syntax.
+local regex_str = #P('/') * l.last_char_includes('!%^&*([{-=+|:;,?<>~') *
+                  l.delimited_range('/', true, false) * S('iomx')^0
+local lit_regex = '%r' * literal_delimitted * S('iomx')^0
+local string = token(l.STRING, (sq_str + dq_str + lit_str + heredoc + cmd_str +
+                                lit_cmd + lit_array) * S('f')^-1) +
+               token(l.REGEX, regex_str + lit_regex)
+
+local word_char = l.alnum + S('_!?')
+
+-- Numbers.
+local dec = l.digit^1 * ('_' * l.digit^1)^0 * S('ri')^-1
+local bin = '0b' * S('01')^1 * ('_' * S('01')^1)^0
+local integer = S('+-')^-1 * (bin + l.hex_num + l.oct_num + dec)
+-- TODO: meta, control, etc. for numeric_literal.
+local numeric_literal = '?' * (l.any - l.space) * -word_char
+local number = token(l.NUMBER, l.float * S('ri')^-1 + integer + numeric_literal)
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match({
+  'BEGIN', 'END', 'alias', 'and', 'begin', 'break', 'case', 'class', 'def',
+  'defined?', 'do', 'else', 'elsif', 'end', 'ensure', 'false', 'for', 'if',
+  'in', 'module', 'next', 'nil', 'not', 'or', 'redo', 'rescue', 'retry',
+  'return', 'self', 'super', 'then', 'true', 'undef', 'unless', 'until', 'when',
+  'while', 'yield', '__FILE__', '__LINE__'
+}, '?!'))
+
+-- Functions.
+local func = token(l.FUNCTION, word_match({
+  'at_exit', 'autoload', 'binding', 'caller', 'catch', 'chop', 'chop!', 'chomp',
+  'chomp!', 'eval', 'exec', 'exit', 'exit!', 'fail', 'fork', 'format', 'gets',
+  'global_variables', 'gsub', 'gsub!', 'iterator?', 'lambda', 'load',
+  'local_variables', 'loop', 'open', 'p', 'print', 'printf', 'proc', 'putc',
+  'puts', 'raise', 'rand', 'readline', 'readlines', 'require', 'select',
+  'sleep', 'split', 'sprintf', 'srand', 'sub', 'sub!', 'syscall', 'system',
+  'test', 'trace_var', 'trap', 'untrace_var'
+}, '?!')) * -S('.:|')
+
+-- Identifiers.
+local word = (l.alpha + '_') * word_char^0
+local identifier = token(l.IDENTIFIER, word)
+
+-- Variables.
+local global_var = '$' * (word + S('!@L+`\'=~/\\,.;<>_*"$?:') + l.digit + '-' *
+                   S('0FadiIKlpvw'))
+local class_var = '@@' * word
+local inst_var = '@' * word
+local variable = token(l.VARIABLE, global_var + class_var + inst_var)
+
+-- Symbols.
+local symbol = token('symbol', ':' * P(function(input, index)
+  if input:sub(index - 2, index - 2) ~= ':' then return index end
+end) * (word_char^1 + sq_str + dq_str))
+
+-- Operators.
+local operator = token(l.OPERATOR, S('!%^&*()[]{}-=+/|:;.,?<>~'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'function', func},
+  {'identifier', identifier},
+  {'comment', comment},
+  {'string', string},
+  {'number', number},
+  {'variable', variable},
+  {'symbol', symbol},
+  {'operator', operator},
+}
+
+M._tokenstyles = {
+  symbol = l.STYLE_CONSTANT
+}
+
+local function disambiguate(text, pos, line, s)
+  return line:sub(1, s - 1):match('^%s*$') and
+         not text:sub(1, pos - 1):match('\\[ \t]*\r?\n$') and 1 or 0
+end
+
+M._foldsymbols = {
+  _patterns = {'%l+', '[%(%)%[%]{}]', '=begin', '=end', '#'},
+  [l.KEYWORD] = {
+    begin = 1, class = 1, def = 1, ['do'] = 1, ['for'] = 1, ['module'] = 1,
+    case = 1,
+    ['if'] = disambiguate, ['while'] = disambiguate,
+    ['unless'] = disambiguate, ['until'] = disambiguate,
+    ['end'] = -1
+  },
+  [l.OPERATOR] = {
+    ['('] = 1, [')'] = -1, ['['] = 1, [']'] = -1, ['{'] = 1, ['}'] = -1
+  },
+  [l.COMMENT] = {
+    ['=begin'] = 1, ['=end'] = -1, ['#'] = l.fold_line_comments('#')
+  }
+}
+
+return M