-- Copyright 2006-2023 Mitchell. See LICENSE.
-- Rebol LPeg lexer.
local lexer = require('lexer')
local token, word_match = lexer.token, lexer.word_match
local P, S = lpeg.P, lpeg.S

local lex = lexer.new('rebol')

-- Whitespace.
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space ^ 1))

-- Comments.
local line_comment = lexer.to_eol(';')
local block_comment = 'comment' * P(' ') ^ -1 * lexer.range('{', '}')
lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))

-- Keywords.
lex:add_rule('keyword', token(lexer.KEYWORD, word_match {
    'abs', 'absolute', 'add', 'and~', 'at', 'back', 'change', 'clear',
    'complement', 'copy', 'cp', 'divide', 'fifth', 'find', 'first', 'fourth',
    'head', 'insert', 'last', 'make', 'max', 'maximum', 'min', 'minimum',
    'multiply', 'negate', 'next', 'or~', 'pick', 'poke', 'power', 'random',
    'remainder', 'remove', 'second', 'select', 'skip', 'sort', 'subtract',
    'tail', 'third', 'to', 'trim', 'xor~', --
    'alias', 'all', 'any', 'arccosine', 'arcsine', 'arctangent', 'bind',
    'break', 'browse', 'call', 'caret-to-offset', 'catch', 'checksum', 'close',
    'comment', 'compose', 'compress', 'cosine', 'debase', 'decompress', 'dehex',
    'detab', 'dh-compute-key', 'dh-generate-key', 'dh-make-key', 'difference',
    'disarm', 'do', 'dsa-generate-key', 'dsa-make-key', 'dsa-make-signature',
    'dsa-verify-signature', 'either', 'else', 'enbase', 'entab', 'exclude',
    'exit', 'exp', 'foreach', 'form', 'free', 'get', 'get-modes', 'halt',
    'hide', 'if', 'in', 'intersect', 'load', 'log-10', 'log-2', 'log-e', 'loop',
    'lowercase', 'maximum-of', 'minimum-of', 'mold', 'not', 'now',
    'offset-to-caret', 'open', 'parse', 'prin', 'print', 'protect', 'q',
    'query', 'quit', 'read', 'read-io', 'recycle', 'reduce', 'repeat', 'return',
    'reverse', 'rsa-encrypt', 'rsa-generate-key', 'rsa-make-key', 'save',
    'secure', 'set', 'set-modes', 'show', 'sine', 'size-text', 'square-root',
    'tangent', 'textinfo', 'throw', 'to-hex', 'to-local-file', 'to-rebol-file',
    'trace', 'try', 'union', 'unique', 'unprotect', 'unset', 'until', 'update',
    'uppercase', 'use', 'wait', 'while', 'write', 'write-io', --
    'basic-syntax-header', 'crlf', 'font-fixed', 'font-sans-serif',
    'font-serif', 'list-words', 'outstr', 'val', 'value', --
    'about', 'alert', 'alter', 'append', 'array', 'ask', 'boot-prefs',
    'build-tag', 'center-face', 'change-dir', 'charset', 'choose', 'clean-path',
    'clear-fields', 'confine', 'confirm', 'context', 'cvs-date', 'cvs-version',
    'decode-cgi', 'decode-url', 'deflag-face', 'delete', 'demo', 'desktop',
    'dirize', 'dispatch', 'do-boot', 'do-events', 'do-face', 'do-face-alt',
    'does', 'dump-face', 'dump-pane', 'echo', 'editor', 'emailer', 'emit',
    'extract', 'find-by-type', 'find-key-face', 'find-window', 'flag-face',
    'flash', 'focus', 'for', 'forall', 'forever', 'forskip', 'func', 'function',
    'get-net-info', 'get-style', 'has', 'help', 'hide-popup', 'import-email',
    'inform', 'input', 'insert-event-func', 'join', 'launch', 'launch-thru',
    'layout', 'license', 'list-dir', 'load-image', 'load-prefs', 'load-thru',
    'make-dir', 'make-face', 'net-error', 'open-events', 'parse-email-addrs',
    'parse-header', 'parse-header-date', 'parse-xml', 'path-thru', 'probe',
    'protect-system', 'read-net', 'read-thru', 'reboot', 'reform', 'rejoin',
    'remold', 'remove-event-func', 'rename', 'repend', 'replace', 'request',
    'request-color', 'request-date', 'request-download', 'request-file',
    'request-list', 'request-pass', 'request-text', 'resend', 'save-prefs',
    'save-user', 'scroll-para', 'send', 'set-font', 'set-net', 'set-para',
    'set-style', 'set-user', 'set-user-name', 'show-popup', 'source',
    'split-path', 'stylize', 'switch', 'throw-on-error', 'to-binary',
    'to-bitset', 'to-block', 'to-char', 'to-date', 'to-decimal', 'to-email',
    'to-event', 'to-file', 'to-get-word', 'to-hash', 'to-idate', 'to-image',
    'to-integer', 'to-issue', 'to-list', 'to-lit-path', 'to-lit-word',
    'to-logic', 'to-money', 'to-none', 'to-pair', 'to-paren', 'to-path',
    'to-refinement', 'to-set-path', 'to-set-word', 'to-string', 'to-tag',
    'to-time', 'to-tuple', 'to-url', 'to-word', 'unfocus', 'uninstall',
    'unview', 'upgrade', 'Usage', 'vbug', 'view', 'view-install', 'view-prefs',
    'what', 'what-dir', 'write-user', 'return', 'at', 'space', 'pad', 'across',
    'below', 'origin', 'guide', 'tabs', 'indent', 'style', 'styles', 'size',
    'sense', 'backcolor', 'do', 'none', --
    'action?', 'any-block?', 'any-function?', 'any-string?', 'any-type?',
    'any-word?', 'binary?', 'bitset?', 'block?', 'char?', 'datatype?', 'date?',
    'decimal?', 'email?', 'empty?', 'equal?', 'error?', 'even?', 'event?',
    'file?', 'function?', 'get-word?', 'greater-or-equal?', 'greater?', 'hash?',
    'head?', 'image?', 'index?', 'integer?', 'issue?', 'length?',
    'lesser-or-equal?', 'lesser?', 'library?', 'list?', 'lit-path?',
    'lit-word?', 'logic?', 'money?', 'native?', 'negative?', 'none?',
    'not-equal?', 'number?', 'object?', 'odd?', 'op?', 'pair?', 'paren?',
    'path?', 'port?', 'positive?', 'refinement?', 'routine?', 'same?',
    'series?', 'set-path?', 'set-word?', 'strict-equal?', 'strict-not-equal?',
    'string?', 'struct?', 'tag?', 'tail?', 'time?', 'tuple?', 'unset?', 'url?',
    'word?', 'zero?', 'connected?', 'crypt-strength?', 'exists-key?', 'input?',
    'script?', 'type?', 'value?', '?', '??', 'dir?', 'exists-thru?', 'exists?',
    'flag-face?', 'found?', 'in-window?', 'info?', 'inside?', 'link-app?',
    'link?', 'modified?', 'offset?', 'outside?', 'screen-offset?', 'size?',
    'span?', 'view?', 'viewed?', 'win-offset?', 'within?', 'action!',
    'any-block!', 'any-function!', 'any-string!', 'any-type!', 'any-word!',
    'binary!', 'bitset!', 'block!', 'char!', 'datatype!', 'date!', 'decimal!',
    'email!', 'error!', 'event!', 'file!', 'function!', 'get-word!', 'hash!',
    'image!', 'integer!', 'issue!', 'library!', 'list!', 'lit-path!',
    'lit-word!', 'logic!', 'money!', 'native!', 'none!', 'number!', 'object!',
    'op!', 'pair!', 'paren!', 'path!', 'port!', 'refinement!', 'routine!',
    'series!', 'set-path!', 'set-word!', 'string!', 'struct!', 'symbol!',
    'tag!', 'time!', 'tuple!', 'unset!', 'url!', 'word!', --
    'true', 'false', 'self'
}))

-- Identifiers.
lex:add_rule('identifier', token(lexer.IDENTIFIER,
                                 (lexer.alpha + '-') * (lexer.alnum + '-') ^ 0))

-- Strings.
local dq_str = lexer.range('"', true)
local br_str = lexer.range('{', '}', false, false, true)
local word_str = "'" * lexer.word
lex:add_rule('string', token(lexer.STRING, dq_str + br_str + word_str))

-- Operators.
lex:add_rule('operator', token(lexer.OPERATOR, S('=<>+/*:()[]')))

-- Fold points.
lex:add_fold_point(lexer.COMMENT, '{', '}')
lex:add_fold_point(lexer.OPERATOR, '[', ']')

lexer.property['scintillua.comment'] = ';'

return lex
