-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
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-- Copyright 2017 Michel Martens.
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-- Crystal LPeg lexer (based on Ruby).
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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('crystal')
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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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alias begin break case class def defined? do else elsif end ensure false for
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if in module next nil not redo rescue retry return self super then true undef
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unless until when while yield __FILE__ __LINE__
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]]))
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-- Functions.
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lex:add_rule('function', token(lexer.FUNCTION, word_match[[
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abort at_exit caller delay exit fork future get_stack_top gets lazy loop main
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p print printf puts raise rand read_line require sleep spawn sprintf system
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with_color
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-- Macros.
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assert_responds_to debugger parallel pp record redefine_main
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]]) * -S('.:|'))
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-- Identifiers.
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local word_char = lexer.alnum + S('_!?')
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local word = (lexer.alpha + '_') * word_char^0
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local identifier = token(lexer.IDENTIFIER, word)
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local delimiter_matches = {['('] = ')', ['['] = ']', ['{'] = '}'}
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local literal_delimitted = P(function(input, index)
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local delimiter = input:sub(index, index)
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if not delimiter:find('[%w\r\n\f\t ]') then -- only non alpha-numerics
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local match_pos, patt
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if delimiter_matches[delimiter] then
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-- Handle nested delimiter/matches in strings.
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local s, e = delimiter, delimiter_matches[delimiter]
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patt = lexer.delimited_range(s..e, false, false, true)
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else
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patt = lexer.delimited_range(delimiter)
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end
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match_pos = lpeg.match(patt, input, index)
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return match_pos or #input + 1
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end
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end)
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-- Comments.
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lex:add_rule('comment', token(lexer.COMMENT, '#' * lexer.nonnewline_esc^0))
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-- Strings.
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local cmd_str = lexer.delimited_range('`')
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local sq_str = lexer.delimited_range("'")
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local dq_str = lexer.delimited_range('"')
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local heredoc = '<<' * P(function(input, index)
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local s, e, indented, _, delimiter =
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input:find('(%-?)(["`]?)([%a_][%w_]*)%2[\n\r\f;]+', index)
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if s == index and delimiter then
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local end_heredoc = (#indented > 0 and '[\n\r\f]+ *' or '[\n\r\f]+')
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local _, e = input:find(end_heredoc..delimiter, 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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-- TODO: regex_str fails with `obj.method /patt/` syntax.
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local regex_str = #P('/') * lexer.last_char_includes('!%^&*([{-=+|:;,?<>~') *
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lexer.delimited_range('/', true, false) * S('iomx')^0
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lex:add_rule('string', token(lexer.STRING, (sq_str + dq_str + heredoc +
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cmd_str) * S('f')^-1) +
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token(lexer.REGEX, regex_str))
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-- Numbers.
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local dec = lexer.digit^1 * ('_' * lexer.digit^1)^0 * S('ri')^-1
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local bin = '0b' * S('01')^1 * ('_' * S('01')^1)^0
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local integer = S('+-')^-1 * (bin + lexer.hex_num + lexer.oct_num + dec)
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-- TODO: meta, control, etc. for numeric_literal.
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local numeric_literal = '?' * (lexer.any - lexer.space) * -word_char
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lex:add_rule('number', token(lexer.NUMBER, lexer.float * S('ri')^-1 + integer +
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numeric_literal))
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-- Variables.
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local global_var = '$' * (word + S('!@L+`\'=~/\\,.;<>_*"$?:') + lexer.digit +
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'-' * S('0FadiIKlpvw'))
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local class_var = '@@' * word
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local inst_var = '@' * word
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lex:add_rule('variable', token(lexer.VARIABLE, global_var + class_var +
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inst_var))
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-- Symbols.
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lex:add_rule('symbol', token('symbol', ':' * P(function(input, index)
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if input:sub(index - 2, index - 2) ~= ':' then return index end
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end) * (word_char^1 + sq_str + dq_str)))
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lex:add_style('symbol', lexer.STYLE_CONSTANT)
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-- Operators.
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lex:add_rule('operator', token(lexer.OPERATOR, S('!%^&*()[]{}-=+/|:;.,?<>~')))
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-- Fold points.
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local function disambiguate(text, pos, line, s)
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return line:sub(1, s - 1):match('^%s*$') and
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not text:sub(1, pos - 1):match('\\[ \t]*\r?\n$') and 1 or 0
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end
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lex:add_fold_point(lexer.KEYWORD, 'begin', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'case', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'class', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'def', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'do', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'for', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'module', 'end')
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lex:add_fold_point(lexer.KEYWORD, 'if', disambiguate)
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lex:add_fold_point(lexer.KEYWORD, 'while', disambiguate)
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lex:add_fold_point(lexer.KEYWORD, 'unless', disambiguate)
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lex:add_fold_point(lexer.KEYWORD, 'until', disambiguate)
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lex:add_fold_point(lexer.OPERATOR, '(', ')')
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lex:add_fold_point(lexer.OPERATOR, '[', ']')
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lex:add_fold_point(lexer.OPERATOR, '{', '}')
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lex:add_fold_point(lexer.OPERATOR, '#', lexer.fold_line_comments('#'))
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return lex
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