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, 59 insertions, 0 deletions

diff --git a/lua/lexers/taskpaper.lua b/lua/lexers/taskpaper.lua
new file mode 100644
index 0000000..5652f3a
--- /dev/null
+++ b/lua/lexers/taskpaper.lua
@@ -0,0 +1,59 @@
+-- Copyright (c) 2016 Larry Hynes. See LICENSE.
+-- Taskpaper LPeg lexer
+
+local l = require('lexer')
+local token = l.token
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+
+local M = {_NAME = 'taskpaper'}
+
+local delimiter = P('    ') + P('\t')
+
+-- Whitespace
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Tags
+local day_tag = token('day_tag', (P('@today') + P('@tomorrow')))
+
+local overdue_tag = token('overdue_tag', P('@overdue'))
+
+local plain_tag = token('plain_tag', P('@') * l.word)
+
+local extended_tag = token('extended_tag',
+                           P('@') * l.word * P('(') *
+                           (l.word + R('09') + P('-'))^1 * P(')'))
+
+-- Projects
+local project = token('project',
+                      l.nested_pair(l.starts_line(l.alnum), ':') * l.newline)
+
+-- Notes
+local note = token('note', delimiter^1 * l.alnum * l.nonnewline^0)
+
+-- Tasks
+local task = token('task', delimiter^1 * P('-') + l.newline)
+
+M._rules = {
+  {'note', note},
+  {'task', task},
+  {'project', project},
+  {'extended_tag', extended_tag},
+  {'day_tag', day_tag},
+  {'overdue_tag', overdue_tag},
+  {'plain_tag', plain_tag},
+  {'whitespace', ws},
+}
+
+M._tokenstyles = {
+  note = l.STYLE_CONSTANT,
+  task = l.STYLE_FUNCTION,
+  project = l.STYLE_TAG,
+  extended_tag = l.STYLE_COMMENT,
+  day_tag = l.STYLE_CLASS,
+  overdue_tag = l.STYLE_PREPROCESSOR,
+  plain_tag = l.STYLE_COMMENT,
+}
+
+M._LEXBYLINE = true
+
+return M