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, 68 insertions, 0 deletions

diff --git a/lua/lexers/toml.lua b/lua/lexers/toml.lua
new file mode 100644
index 0000000..5a27c97
--- /dev/null
+++ b/lua/lexers/toml.lua
@@ -0,0 +1,68 @@
+-- Copyright 2015-2016 Alejandro Baez (https://keybase.io/baez). See LICENSE.
+-- TOML 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 = 'toml'}
+
+-- Whitespace
+local indent = #l.starts_line(S(' \t')) *
+               (token(l.WHITESPACE, ' ') + token('indent_error', '\t'))^1
+local ws = token(l.WHITESPACE, S(' \t')^1 + l.newline^1)
+
+-- Comments.
+local comment = token(l.COMMENT, '#' * l.nonnewline^0)
+
+-- Strings.
+local string = token(l.STRING, l.delimited_range("'") + l.delimited_range('"'))
+
+-- Numbers.
+local number = token(l.NUMBER, l.float + l.integer)
+
+-- Datetime.
+local ts = token('timestamp', l.digit * l.digit * l.digit * l.digit * -- year
+                              '-' * l.digit * l.digit^-1 * -- month
+                              '-' * l.digit * l.digit^-1 * -- day
+                              ((S(' \t')^1 + S('tT'))^-1 * -- separator
+                               l.digit * l.digit^-1 * -- hour
+                               ':' * l.digit * l.digit * -- minute
+                               ':' * l.digit * l.digit * -- second
+                               ('.' * l.digit^0)^-1 * -- fraction
+                               ('Z' + -- timezone
+                                S(' \t')^0 * S('-+') * l.digit * l.digit^-1 *
+                                (':' * l.digit * l.digit)^-1)^-1)^-1)
+
+-- kewwords.
+local keyword = token(l.KEYWORD, word_match{
+  'true', 'false'
+})
+
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('#=+-,.{}[]()'))
+
+M._rules = {
+  {'indent', indent},
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'identifier', identifier},
+  {'operator', operator},
+  {'string', string},
+  {'comment', comment},
+  {'number', number},
+  {'timestamp', ts},
+}
+
+M._tokenstyles = {
+  indent_error = 'back:red',
+  timestamp = l.STYLE_NUMBER,
+}
+
+M._FOLDBYINDENTATION = true
+
+return M