-- 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
|
