55 lines
1.7 KiB
Lua
55 lines
1.7 KiB
Lua
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-- Copyright 2017-2019 Michael Forney. See License.txt.
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-- rc LPeg lexer.
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local lexer = require('lexer')
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local token, word_match = lexer.token, lexer.word_match
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local P, R, S = lpeg.P, lpeg.R, lpeg.S
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local lex = lexer.new('rc')
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-- Whitespace.
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lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
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-- Keywords.
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lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
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for in while if not switch fn builtin cd eval exec exit flag rfork shift
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ulimit umask wait whatis . ~
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]]))
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-- Identifiers.
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lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
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-- Strings.
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local str = lexer.delimited_range("'", false, true)
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local heredoc = '<<' * P(function(input, index)
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local s, e, _, delimiter = input:find('[ \t]*(["\']?)([%w!"%%+,-./:?@_~]+)%1',
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index)
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if s == index and delimiter then
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delimiter = delimiter:gsub('[%%+-.?]', '%%%1')
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local _, e = input:find('[\n\r]'..delimiter..'[\n\r]', e)
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return e and e + 1 or #input + 1
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end
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end)
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lex:add_rule('string', token(lexer.STRING, str + heredoc))
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-- Comments.
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lex:add_rule('comment', token(lexer.COMMENT, '#' * lexer.nonnewline^0))
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-- Numbers.
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lex:add_rule('number', token(lexer.NUMBER, lexer.integer + lexer.float))
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-- Variables.
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lex:add_rule('variable', token(lexer.VARIABLE, '$' * S('"#')^-1 *
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('*' + lexer.digit^1 +
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lexer.word)))
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('@`=!<>*&^|;?()[]{}') +
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'\\\n'))
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-- Fold points.
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lex:add_fold_point(lexer.OPERATOR, '{', '}')
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lex:add_fold_point(lexer.COMMENT, '#', lexer.fold_line_comments('#'))
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return lex
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