58 lines
1.6 KiB
Lua
Executable File
58 lines
1.6 KiB
Lua
Executable File
-- Copyright 2015-2019 David B. Lamkins <david@lamkins.net>. See License.txt.
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-- APL 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('apl')
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-- Whitespace.
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lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
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-- Comments.
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lex:add_rule('comment', token(lexer.COMMENT, (P('⍝') + '#') *
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lexer.nonnewline^0))
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-- Strings.
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local sq_str = lexer.delimited_range("'", false, true)
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local dq_str = lexer.delimited_range('"')
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lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
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-- Numbers.
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local dig = R('09')
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local rad = P('.')
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local exp = S('eE')
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local img = S('jJ')
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local sgn = P('¯')^-1
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local float = sgn * (dig^0 * rad * dig^1 + dig^1 * rad * dig^0 + dig^1) *
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(exp * sgn *dig^1)^-1
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lex:add_rule('number', token(lexer.NUMBER, float * img * float + float))
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-- Keywords.
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lex:add_rule('keyword', token(lexer.KEYWORD, P('⍞') + 'χ' + '⍺' + '⍶' + '⍵' +
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'⍹' + '⎕' * R('AZ', 'az')^0))
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-- Names.
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local n1l = R('AZ', 'az')
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local n1b = P('_') + '∆' + '⍙'
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local n2l = n1l + R('09')
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local n2b = n1b + '¯'
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local n1 = n1l + n1b
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local n2 = n2l + n2b
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local name = n1 * n2^0
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-- Labels.
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lex:add_rule('label', token(lexer.LABEL, name * ':'))
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-- Variables.
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lex:add_rule('variable', token(lexer.VARIABLE, name))
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-- Special.
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lex:add_rule('special', token(lexer.TYPE, S('{}[]();') + '←' + '→' + '◊'))
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-- Nabla.
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lex:add_rule('nabla', token(lexer.PREPROCESSOR, P('∇') + '⍫'))
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return lex
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