Add `xs` lexer and mappings.

1 files changed, 75 insertions, 0 deletions

diff --git a/lua/lexers/xs.lua b/lua/lexers/xs.lua
new file mode 100644
index 0000000..2243a6f
--- /dev/null
+++ b/lua/lexers/xs.lua
@@ -0,0 +1,75 @@
+-- Copyright 2017 Michael Forney. See LICENSE.
+-- Copyright 2017 David B. Lamkins. See LICENSE.
+-- xs 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 = 'xs'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local comment = token(l.COMMENT, '#' * l.nonnewline^0)
+
+-- Strings.
+local str = l.delimited_range("'", false, true)
+local herestr = '<<<' * str
+local heredoc = '<<' * P(function(input, index)
+  local s, e, _, delimiter =
+    input:find('[ \t]*(["\']?)([%w!"%%+,-./:?@_~]+)%1', index)
+  if s == index and delimiter then
+    delimiter = delimiter:gsub('[%%+-.?]', '%%%1')
+    local _, e = input:find('[\n\r]'..delimiter..'[\n\r]', e)
+    return e and e + 1 or #input + 1
+  end
+end)
+local string = token(l.STRING, str + herestr + heredoc)
+
+-- Numbers.
+local number = token(l.NUMBER, l.integer + l.float)
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match({
+  'access', 'alias', 'catch', 'cd', 'dirs', 'echo', 'else', 'escape', 'eval',
+  'exec', 'exit', 'false', 'fn-', 'fn', 'for', 'forever', 'fork', 'history',
+  'if', 'jobs', 'let', 'limit', 'local', 'map', 'omap', 'popd', 'printf',
+  'pushd', 'read', 'result', 'set-', 'switch', 'throw', 'time', 'true',
+  'umask', 'until', 'unwind-protect', 'var', 'vars', 'wait', 'whats', 'while',
+  ':lt', ':le', ':gt', ':ge', ':eq', ':ne', '~', '~~', '...', '.',
+}, '!"%*+,-./:?@[]~'))
+
+-- Constants.
+local constant = token(l.CONSTANT, '$&' * l.word)
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Variables.
+local variable = token(l.VARIABLE,
+                       '$' * S('"#')^-1 * ('*' + l.digit^1 + l.word))
+
+-- Operators.
+local operator = token(l.OPERATOR, S('@`=!<>*&^|;?()[]{}') + '\\\n')
+
+M._rules = {
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'constant', constant},
+  {'identifier', identifier},
+  {'string', string},
+  {'comment', comment},
+  {'number', number},
+  {'variable', variable},
+  {'operator', operator},
+}
+
+M._foldsymbols = {
+  _patterns = {'[{}]', '#'},
+  [l.OPERATOR] = {['{'] = 1, ['}'] = -1},
+  [l.COMMENT] = {['#'] = l.fold_line_comments('#')}
+}
+
+return M