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, 82 insertions, 0 deletions

diff --git a/lua/lexers/powershell.lua b/lua/lexers/powershell.lua
new file mode 100644
index 0000000..4a3ba07
--- /dev/null
+++ b/lua/lexers/powershell.lua
@@ -0,0 +1,82 @@
+-- Copyright 2015-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- PowerShell LPeg lexer.
+-- Contributed by Jeff Stone.
+
+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 = 'powershell'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local comment = token(l.COMMENT, '#' * l.nonnewline^0)
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match({
+  'Begin', 'Break', 'Continue', 'Do', 'Else', 'End', 'Exit', 'For', 'ForEach',
+  'ForEach-Object', 'Get-Date', 'Get-Random', 'If', 'Param', 'Pause',
+  'Powershell', 'Process', 'Read-Host', 'Return', 'Switch', 'While',
+  'Write-Host'
+}, '-', true))
+
+-- Comparison Operators.
+local comparison = token(l.KEYWORD, '-' * word_match({
+  'and', 'as', 'band', 'bor', 'contains', 'eq', 'ge', 'gt', 'is', 'isnot', 'le',
+  'like', 'lt', 'match', 'ne', 'nomatch', 'not', 'notcontains', 'notlike', 'or',
+  'replace'
+}, nil, true))
+
+-- Parameters.
+local parameter = token(l.KEYWORD, '-' * word_match({
+  'Confirm', 'Debug', 'ErrorAction', 'ErrorVariable', 'OutBuffer',
+  'OutVariable', 'Verbose', 'WhatIf'
+}, nil, true))
+
+-- Properties.
+local property = token(l.KEYWORD, '.' * word_match({
+  'day', 'dayofweek', 'dayofyear', 'hour', 'millisecond', 'minute', 'month',
+  'second', 'timeofday', 'year'
+}, nil, true))
+
+-- Types.
+local type = token(l.KEYWORD, '[' * word_match({
+  'array', 'boolean', 'byte', 'char', 'datetime', 'decimal', 'double',
+  'hashtable', 'int', 'long', 'single', 'string', 'xml'
+}, nil, true) * ']')
+
+-- Variables.
+local variable = token(l.VARIABLE, '$' * (l.digit^1 + l.word +
+                                          l.delimited_range('{}', true, true)))
+
+-- Strings.
+local string = token(l.STRING, l.delimited_range('"', true))
+
+-- Numbers.
+local number = token(l.NUMBER, l.float + l.integer)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('=!<>+-/*^&|~.,:;?()[]{}%`'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'comment', comment},
+  {'keyword', keyword},
+  {'comparison', comparison},
+  {'parameter', parameter},
+  {'property', property},
+  {'type', type},
+  {'variable', variable},
+  {'string', string},
+  {'number', number},
+  {'operator', operator},
+}
+
+M._foldsymbols = {
+  _patterns = {'[{}]'},
+  [l.OPERATOR] = {['{'] = 1, ['}'] = -1}
+}
+
+return M