66 lines
2.8 KiB
Lua
66 lines
2.8 KiB
Lua
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-- Copyright 2013-2019 Michael T. Richter. See License.txt.
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-- SNOBOL4 lexer.
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-- This lexer works with classic SNOBOL4 as well as the CSNOBOL4 extensions.
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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 B, P, R, S, V = lpeg.B, lpeg.P, lpeg.R, lpeg.S, lpeg.V
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local M = { _NAME = 'snobol4' }
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-- Helper patterns.
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local dotted_id = lexer.word * (P'.' * lexer.word)^0
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local dq_str = lexer.delimited_range('"', true, true)
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local sq_str = lexer.delimited_range("'", true, true)
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local branch = B(lexer.space * P':(') * dotted_id * #P')'
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local sbranch = B(lexer.space * P':' * S'SF' * '(') * dotted_id * #P')'
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local sbranchx = B(P')' * S'SF' * P'(') * dotted_id * #P')'
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-- Token definitions.
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local bif = token(lexer.FUNCTION, word_match({
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'APPLY', 'ARRAY', 'CHAR', 'CONVERT', 'COPY', 'DATA', 'DATE', 'DIFFER', 'DUPL',
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'EQ', 'EVAL', 'FILE_ABSPATH', 'FILE_ISDIR', 'FREEZE', 'FUNCTION', 'GE', 'GT',
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'HOST', 'IDENT', 'INTEGER', 'IO_FINDUNIT', 'ITEM', 'LABEL', 'LOAD', 'LPAD',
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'LE', 'LGT', 'LT', 'NE', 'OPSYN', 'ORD', 'PROTOTYPE', 'REMDR', 'REPLACE',
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'REVERSE', 'RPAD', 'RSORT', 'SERV_LISTEN', 'SET', 'SETEXIT', 'SIZE', 'SORT',
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'SQRT', 'SSET', 'SUBSTR', 'TABLE', 'THAW', 'TIME', 'TRACE', 'TRIM', 'UNLOAD',
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'VALUE', 'VDIFFER',
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}, '', true) * #lexer.delimited_range('()', false, true, true))
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local comment = token(lexer.COMMENT,
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lexer.starts_line(S'*#|;!' * lexer.nonnewline^0))
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local control = token(lexer.PREPROCESSOR, lexer.starts_line(P'-' * lexer.word))
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local identifier = token(lexer.DEFAULT, dotted_id)
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local keyword = token(lexer.KEYWORD, word_match({
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'ABORT', 'ARRAY', 'CONTINUE', 'DEFINE', 'END', 'FRETURN', 'INPUT', 'NRETURN',
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'OUTPUT', 'PUNCH', 'RETURN', 'SCONTINUE', 'TABLE',
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}, '', true) + P'&' * lexer.word)
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local label = token(lexer.LABEL, lexer.starts_line(dotted_id))
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local number = token(lexer.NUMBER, lexer.float + lexer.integer)
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local operator = token(lexer.OPERATOR, S'¬?$.!%*/#+-@⊥&^~\\=')
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local pattern = lexer.token(lexer.CLASS, word_match({ -- keep distinct
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'ABORT', 'ANY', 'ARB', 'ARBNO', 'BAL', 'BREAK', 'BREAKX', 'FAIL', 'FENCE',
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'LEN', 'NOTANY', 'POS', 'REM', 'RPOS', 'RTAB', 'SPAN', 'SUCCEED', 'TAB',
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}, '', true) * #lexer.delimited_range('()', false, true, true))
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local str = token(lexer.STRING, sq_str + dq_str)
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local target = token(lexer.LABEL, branch + sbranch + sbranchx)
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local ws = token(lexer.WHITESPACE, lexer.space^1)
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M._rules = {
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{ 'comment', comment },
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{ 'control', control },
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{ 'string', str },
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{ 'number', number },
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{ 'keyword', keyword },
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{ 'label', label },
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{ 'target', target },
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{ 'pattern', pattern },
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{ 'built-in', bif },
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{ 'operator', operator },
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{ 'identifier', identifier },
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{ 'whitespace', ws },
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}
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return M
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