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oasis-root

Compiled tree of Oasis Linux based on own branch at <https://hacktivis.me/git/oasis/> git clone https://anongit.hacktivis.me/git/oasis-root.git

snobol4.lua (2600B)

    

  1. -- Copyright 2013-2024 Michael T. Richter. See LICENSE.
  2. -- SNOBOL4 lexer.
  3. -- This lexer works with classic SNOBOL4 as well as the CSNOBOL4 extensions.
  5. local lexer = require('lexer')
  6. local token, word_match = lexer.token, lexer.word_match
  7. local B, P, S = lpeg.B, lpeg.P, lpeg.S
  9. local lex = lexer.new('snobol4')
  11. -- Whitespace.
  12. lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
  14. -- Keywords.
  15. lex:add_rule('keyword', token(lexer.KEYWORD, word_match({
  16.   'ABORT', 'ARRAY', 'CONTINUE', 'DEFINE', 'END', 'FRETURN', 'INPUT', 'NRETURN', 'OUTPUT', 'PUNCH',
  17.   'RETURN', 'SCONTINUE', 'TABLE'
  18. }, true) + '&' * lexer.word))
  20. -- Helper patterns.
  21. local dotted_id = lexer.word * ('.' * lexer.word)^0
  23. -- Labels.
  24. lex:add_rule('label', token(lexer.LABEL, lexer.starts_line(dotted_id)))
  26. -- Targets.
  27. local branch = B(lexer.space * ':(') * dotted_id * #P(')')
  28. local sbranch = B(lexer.space * ':' * S('SsFf') * '(') * dotted_id * #P(')')
  29. local sbranchx = B(')' * S('SsFf') * '(') * dotted_id * #P(')')
  30. lex:add_rule('target', token(lexer.LABEL, branch + sbranch + sbranchx))
  32. -- Patterns.
  33. lex:add_rule('pattern', lexer.token(lexer.CLASS, word_match({
  34.   -- Keep distinct.
  35.   'ABORT', 'ANY', 'ARB', 'ARBNO', 'BAL', 'BREAK', 'BREAKX', 'FAIL', 'FENCE', 'LEN', 'NOTANY', 'POS',
  36.   'REM', 'RPOS', 'RTAB', 'SPAN', 'SUCCEED', 'TAB'
  37. }, true) * #P('(')))
  39. -- Token definitions.
  40. lex:add_rule('built-in', token(lexer.FUNCTION, word_match({
  41.   'APPLY', 'ARRAY', 'CHAR', 'CONVERT', 'COPY', 'DATA', 'DATE', 'DIFFER', 'DUPL', 'EQ', 'EVAL',
  42.   'FILE_ABSPATH', 'FILE_ISDIR', 'FREEZE', 'FUNCTION', 'GE', 'GT', 'HOST', 'IDENT', 'INTEGER',
  43.   'IO_FINDUNIT', 'ITEM', 'LABEL', 'LOAD', 'LPAD', 'LE', 'LGT', 'LT', 'NE', 'OPSYN', 'ORD',
  44.   'PROTOTYPE', 'REMDR', 'REPLACE', 'REVERSE', 'RPAD', 'RSORT', 'SERV_LISTEN', 'SET', 'SETEXIT',
  45.   'SIZE', 'SORT', 'SQRT', 'SSET', 'SUBSTR', 'TABLE', 'THAW', 'TIME', 'TRACE', 'TRIM', 'UNLOAD',
  46.   'VALUE', 'VDIFFER'
  47. }, true) * #P('(')))
  49. -- Identifiers.
  50. lex:add_rule('identifier', token(lexer.DEFAULT, dotted_id))
  52. -- Strings.
  53. local dq_str = lexer.range('"', true, false)
  54. local sq_str = lexer.range("'", true, false)
  55. lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
  57. -- Comments.
  58. lex:add_rule('comment', token(lexer.COMMENT, lexer.starts_line(lexer.to_eol(S('*#|;!')))))
  60. -- Numbers.
  61. lex:add_rule('number', token(lexer.NUMBER, lexer.number))
  63. -- Control.
  64. lex:add_rule('control', token(lexer.PREPROCESSOR, lexer.starts_line('-' * lexer.word)))
  66. -- Operators.
  67. lex:add_rule('operator', token(lexer.OPERATOR, S'¬?$.!%*/#+-@⊥&^~\\='))
  69. lexer.property['scintillua.comment'] = '#'
  71. return lex