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, 42 insertions, 0 deletions

diff --git a/lua/lexers/asp.lua b/lua/lexers/asp.lua
new file mode 100644
index 0000000..dc1b0e9
--- /dev/null
+++ b/lua/lexers/asp.lua
@@ -0,0 +1,42 @@
+-- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- ASP 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 = 'asp'}
+
+-- Embedded in HTML.
+local html = l.load('html')
+
+-- Embedded VB.
+local vb = l.load('vb')
+local vb_start_rule = token('asp_tag', '<%' * P('=')^-1)
+local vb_end_rule = token('asp_tag', '%>')
+l.embed_lexer(html, vb, vb_start_rule, vb_end_rule)
+
+-- Embedded VBScript.
+local vbs = l.load('vbscript')
+local script_element = word_match({'script'}, nil, html.case_insensitive_tags)
+local vbs_start_rule = #(P('<') * script_element * (P(function(input, index)
+  if input:find('^%s+language%s*=%s*(["\'])vbscript%1', index) or
+     input:find('^%s+type%s*=%s*(["\'])text/vbscript%1', index) then
+    return index
+  end
+end) + '>')) * html.embed_start_tag -- <script language="vbscript">
+local vbs_end_rule = #('</' * script_element * l.space^0 * '>') *
+                     html.embed_end_tag -- </script>
+l.embed_lexer(html, vbs, vbs_start_rule, vbs_end_rule)
+
+M._tokenstyles = {
+  asp_tag = l.STYLE_EMBEDDED
+}
+
+local _foldsymbols = html._foldsymbols
+_foldsymbols._patterns[#_foldsymbols._patterns + 1] = '<%%'
+_foldsymbols._patterns[#_foldsymbols._patterns + 1] = '%%>'
+_foldsymbols.asp_tag = {['<%'] = 1, ['%>'] = -1}
+M._foldsymbols = _foldsymbols
+
+return M