Added optional Lua lexer support.

This support is disabled by default and must be enabled via compile-time option.

1 files changed, 54 insertions, 0 deletions

diff --git a/lexlua/rc.lua b/lexlua/rc.lua
new file mode 100644
index 000000000..868ddbc49
--- /dev/null
+++ b/lexlua/rc.lua
@@ -0,0 +1,54 @@
+-- Copyright 2017-2018 Michael Forney. See License.txt.
+-- rc LPeg lexer.
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+
+local lex = lexer.new('rc')
+
+-- Whitespace.
+lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  for in while if not switch fn builtin cd eval exec exit flag rfork shift
+  ulimit umask wait whatis . ~
+]]))
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
+
+-- Strings.
+local str = lexer.delimited_range("'", false, true)
+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)
+lex:add_rule('string', token(lexer.STRING, str + heredoc))
+
+-- Comments.
+lex:add_rule('comment', token(lexer.COMMENT, '#' * lexer.nonnewline^0))
+
+-- Numbers.
+lex:add_rule('number', token(lexer.NUMBER, lexer.integer + lexer.float))
+
+-- Variables.
+lex:add_rule('variable', token(lexer.VARIABLE, '$' * S('"#')^-1 *
+                                               ('*' + lexer.digit^1 +
+                                                lexer.word)))
+
+-- Operators.
+lex:add_rule('operator', token(lexer.OPERATOR, S('@`=!<>*&^|;?()[]{}') +
+                                               '\\\n'))
+
+-- Fold points.
+lex:add_fold_point(lexer.OPERATOR, '{', '}')
+lex:add_fold_point(lexer.COMMENT, '#', lexer.fold_line_comments('#'))
+
+return lex