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, 0 insertions, 62 deletions

diff --git a/lexers/pure.lua b/lexers/pure.lua
deleted file mode 100644
index 256a2dc..0000000
--- a/lexers/pure.lua
+++ /dev/null
@@ -1,62 +0,0 @@
--- Copyright 2015-2016 David B. Lamkins <david@lamkins.net>. See LICENSE.
--- pure LPeg lexer, see http://purelang.bitbucket.org/
-
-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 = 'pure'}
-
--- 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))
-
--- Numbers.
-local bin = '0' * S('Bb') * S('01')^1
-local hex = '0' * S('Xx') * (R('09') + R('af') + R('AF'))^1
-local dec = R('09')^1
-local int = (bin + hex + dec) * P('L')^-1
-local rad = P('.') - P('..')
-local exp = (S('Ee') * S('+-')^-1 * int)^-1
-local flt = int * (rad * dec)^-1 * exp + int^-1 * rad * dec * exp
-local number = token(l.NUMBER, flt + int)
-
--- Keywords.
-local keyword = token(l.KEYWORD, word_match{
-  'namespace', 'with', 'end', 'using', 'interface', 'extern', 'let', 'const',
-  'def', 'type', 'public', 'private', 'nonfix', 'outfix', 'infix', 'infixl',
-  'infixr', 'prefix', 'postfix', 'if', 'otherwise', 'when', 'case', 'of',
-  'then', 'else'
-})
-
--- Identifiers.
-local identifier = token(l.IDENTIFIER, l.word)
-
--- Operators.
-local punct = S('+-/*%<>~!=^&|?~:;,.()[]{}@#$`\\\'')
-local dots = P('..')
-local operator = token(l.OPERATOR, dots + punct)
-
--- Pragmas.
-local hashbang = l.starts_line('#!') * (l.nonnewline - P('//'))^0
-local pragma = token(l.PREPROCESSOR, hashbang)
-
-M._rules = {
-  {'whitespace', ws},
-  {'comment', comment},
-  {'pragma', pragma},
-  {'keyword', keyword},
-  {'number', number},
-  {'operator', operator},
-  {'identifier', identifier},
-  {'string', string},
-}
-
-return M