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, 87 insertions, 0 deletions

diff --git a/lua/lexers/objective_c.lua b/lua/lexers/objective_c.lua
new file mode 100644
index 0000000..4722c2c
--- /dev/null
+++ b/lua/lexers/objective_c.lua
@@ -0,0 +1,87 @@
+-- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- Objective C 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 = 'objective_c'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local line_comment = '//' * l.nonnewline_esc^0
+local block_comment = '/*' * (l.any - '*/')^0 * P('*/')^-1
+local comment = token(l.COMMENT, line_comment + block_comment)
+
+-- Strings.
+local sq_str = P('L')^-1 * l.delimited_range("'", true)
+local dq_str = P('L')^-1 * l.delimited_range('"', true)
+local string = token(l.STRING, sq_str + dq_str)
+
+-- Numbers.
+local number = token(l.NUMBER, l.float + l.integer)
+
+-- Preprocessor.
+local preproc_word = word_match{
+  'define', 'elif', 'else', 'endif', 'error', 'if', 'ifdef',
+  'ifndef', 'import', 'include', 'line', 'pragma', 'undef',
+  'warning'
+}
+local preproc = token(l.PREPROCESSOR,
+                      l.starts_line('#') * S('\t ')^0 * preproc_word *
+                      (l.nonnewline_esc^1 + l.space * l.nonnewline_esc^0))
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match({
+  -- From C.
+  'asm', 'auto', 'break', 'case', 'const', 'continue', 'default', 'do', 'else',
+  'extern', 'false', 'for', 'goto', 'if', 'inline', 'register', 'return',
+  'sizeof', 'static', 'switch', 'true', 'typedef', 'void', 'volatile', 'while',
+  'restrict', '_Bool', '_Complex', '_Pragma', '_Imaginary',
+  -- Objective C.
+  'oneway', 'in', 'out', 'inout', 'bycopy', 'byref', 'self', 'super',
+  -- Preprocessor directives.
+  '@interface', '@implementation', '@protocol', '@end', '@private',
+  '@protected', '@public', '@class', '@selector', '@encode', '@defs',
+  '@synchronized', '@try', '@throw', '@catch', '@finally',
+  -- Constants.
+  'TRUE', 'FALSE', 'YES', 'NO', 'NULL', 'nil', 'Nil', 'METHOD_NULL'
+}, '@'))
+
+-- Types.
+local type = token(l.TYPE, word_match{
+  'apply_t', 'id', 'Class', 'MetaClass', 'Object', 'Protocol', 'retval_t',
+  'SEL', 'STR', 'IMP', 'BOOL', 'TypedStream'
+})
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('+-/*%<>!=^&|?~:;.()[]{}'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'type', type},
+  {'string', string},
+  {'identifier', identifier},
+  {'comment', comment},
+  {'number', number},
+  {'preproc', preproc},
+  {'operator', operator},
+}
+
+M._foldsymbols = {
+  _patterns = {'%l+', '[{}]', '/%*', '%*/', '//'},
+  [l.PREPROCESSOR] = {
+    region = 1, endregion = -1,
+    ['if'] = 1, ifdef = 1, ifndef = 1, endif = -1
+  },
+  [l.OPERATOR] = {['{'] = 1, ['}'] = -1},
+  [l.COMMENT] = {['/*'] = 1, ['*/'] = -1, ['//'] = l.fold_line_comments('//')}
+}
+
+return M