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, 74 insertions, 0 deletions

diff --git a/lua/lexers/antlr.lua b/lua/lexers/antlr.lua
new file mode 100644
index 0000000..91dbd60
--- /dev/null
+++ b/lua/lexers/antlr.lua
@@ -0,0 +1,74 @@
+-- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- ANTLR 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 = 'antlr'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local line_comment = '//' * l.nonnewline^0
+local block_comment = '/*' * (l.any - '*/')^0 * P('*/')^-1
+local comment = token(l.COMMENT, line_comment + block_comment)
+
+-- Strings.
+local string = token(l.STRING, l.delimited_range("'", true))
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match{
+  'abstract', 'break', 'case', 'catch', 'continue', 'default', 'do', 'else',
+  'extends', 'final', 'finally', 'for', 'if', 'implements', 'instanceof',
+  'native', 'new', 'private', 'protected', 'public', 'return', 'static',
+  'switch', 'synchronized', 'throw', 'throws', 'transient', 'try', 'volatile',
+  'while', 'package', 'import', 'header', 'options', 'tokens', 'strictfp',
+  'false', 'null', 'super', 'this', 'true'
+})
+
+-- Types.
+local type = token(l.TYPE, word_match{
+  'boolean', 'byte', 'char', 'class', 'double', 'float', 'int', 'interface',
+  'long', 'short', 'void'
+})
+
+-- Functions.
+local func = token(l.FUNCTION, 'assert')
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('$@:;|.=+*?~!^>-()[]{}'))
+
+-- Actions.
+local action = #P('{') * operator * token('action', (1 - P('}'))^0) *
+               (#P('}') * operator)^-1
+
+M._rules = {
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'type', type},
+  {'function', func},
+  {'identifier', identifier},
+  {'string', string},
+  {'comment', comment},
+  {'action', action},
+  {'operator', operator},
+}
+
+M._tokenstyles = {
+  action = l.STYLE_NOTHING
+}
+
+M._foldsymbols = {
+  _patterns = {'[:;%(%){}]', '/%*', '%*/', '//'},
+  [l.OPERATOR] = {
+    [':'] = 1, [';'] = -1, ['('] = 1, [')'] = -1, ['{'] = 1, ['}'] = -1
+  },
+  [l.COMMENT] = {['/*'] = 1, ['*/'] = -1, ['//'] = l.fold_line_comments('//')}
+}
+
+return M