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, 101 insertions, 0 deletions

diff --git a/lua/lexers/verilog.lua b/lua/lexers/verilog.lua
new file mode 100644
index 0000000..9160e0f
--- /dev/null
+++ b/lua/lexers/verilog.lua
@@ -0,0 +1,101 @@
+-- Copyright 2006-2016 Mitchell mitchell.att.foicica.com. See LICENSE.
+-- Verilog 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 = 'verilog'}
+
+-- 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('"'))
+
+-- Numbers.
+local bin_suffix = S('bB') * S('01_xXzZ')^1
+local oct_suffix = S('oO') * S('01234567_xXzZ')^1
+local dec_suffix = S('dD') * S('0123456789_xXzZ')^1
+local hex_suffix = S('hH') * S('0123456789abcdefABCDEF_xXzZ')^1
+local number = token(l.NUMBER, (l.digit + '_')^1 + "'" *
+                               (bin_suffix + oct_suffix + dec_suffix +
+                                hex_suffix))
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match({
+  'always', 'assign', 'begin', 'case', 'casex', 'casez', 'default', 'deassign',
+  'disable', 'else', 'end', 'endcase', 'endfunction', 'endgenerate',
+  'endmodule', 'endprimitive', 'endspecify', 'endtable', 'endtask', 'for',
+  'force', 'forever', 'fork', 'function', 'generate', 'if', 'initial', 'join',
+  'macromodule', 'module', 'negedge', 'posedge', 'primitive', 'repeat',
+  'release', 'specify', 'table', 'task', 'wait', 'while',
+  -- Compiler directives.
+  '`include', '`define', '`undef', '`ifdef', '`ifndef', '`else', '`endif',
+  '`timescale', '`resetall', '`signed', '`unsigned', '`celldefine',
+  '`endcelldefine', '`default_nettype', '`unconnected_drive',
+  '`nounconnected_drive', '`protect', '`endprotect', '`protected',
+  '`endprotected', '`remove_gatename', '`noremove_gatename', '`remove_netname',
+  '`noremove_netname', '`expand_vectornets', '`noexpand_vectornets',
+  '`autoexpand_vectornets',
+  -- Signal strengths.
+  'strong0', 'strong1', 'pull0', 'pull1', 'weak0', 'weak1', 'highz0', 'highz1',
+  'small', 'medium', 'large'
+}, '`01'))
+
+-- Function.
+local func = token(l.FUNCTION, word_match({
+  '$stop', '$finish', '$time', '$stime', '$realtime', '$settrace',
+  '$cleartrace', '$showscopes', '$showvars', '$monitoron', '$monitoroff',
+  '$random', '$printtimescale', '$timeformat', '$display',
+  -- Built-in primitives.
+  'and', 'nand', 'or', 'nor', 'xor', 'xnor', 'buf', 'bufif0', 'bufif1', 'not',
+  'notif0', 'notif1', 'nmos', 'pmos', 'cmos', 'rnmos', 'rpmos', 'rcmos', 'tran',
+  'tranif0', 'tranif1', 'rtran', 'rtranif0', 'rtranif1', 'pullup', 'pulldown'
+}, '$01'))
+
+-- Types.
+local type = token(l.TYPE, word_match({
+  'integer', 'reg', 'time', 'realtime', 'defparam', 'parameter', 'event',
+  'wire', 'wand', 'wor', 'tri', 'triand', 'trior', 'tri0', 'tri1', 'trireg',
+  'vectored', 'scalared', 'input', 'output', 'inout',
+  'supply0', 'supply1'
+}, '01'))
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('=~+-/*<>%&|^~,:;()[]{}'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'number', number},
+  {'keyword', keyword},
+  {'function', func},
+  {'type', type},
+  {'identifier', identifier},
+  {'string', string},
+  {'comment', comment},
+  {'operator', operator},
+}
+
+M._foldsymbols = {
+  _patterns = {'[a-z]+', '[%(%){}]', '/%*', '%*/', '//'},
+  [l.KEYWORD] = {
+    case = 1, casex = 1, casez = 1, endcase = -1, ['function'] = 1,
+    endfunction = -1, fork = 1, join = -1, table = 1, endtable = -1, task = 1,
+    endtask = -1, generate = 1, endgenerate = -1, specify = 1, endspecify = -1,
+    primitive = 1, endprimitive = -1, ['module'] = 1, endmodule = -1, begin = 1,
+    ['end'] = -1
+  },
+  [l.OPERATOR] = {['('] = 1, [')'] = -1, ['{'] = 1, ['}'] = -1},
+  [l.COMMENT] = {['/*'] = 1, ['*/'] = -1, ['//'] = l.fold_line_comments('//')}
+}
+
+return M