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-- Copyright 2017 Michael Forney. See LICENSE.
-- rc 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 = 'rc'}
-- 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 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 + heredoc)
-- Numbers.
local number = token(l.NUMBER, l.integer + l.float)
-- Keywords.
local keyword = token(l.KEYWORD, word_match({
'for', 'in', 'while', 'if', 'not', 'switch', 'fn',
'builtin', 'cd', 'eval', 'exec', 'exit', 'flag', 'rfork', 'shift', 'ulimit',
'umask', 'wait', 'whatis', '.', '~',
}, '!"%*+,-./:?@[]~'))
-- 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},
{'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
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