1 files changed, 127 insertions, 0 deletions
diff --git a/lua/lexers/ruby.lua b/lua/lexers/ruby.lua
new file mode 100644
index 0000000..51334f2
--- /dev/null
+++ b/lua/lexers/ruby.lua
@@ -0,0 +1,127 @@
+-- Copyright 2006-2024 Mitchell. See LICENSE.
+-- Ruby LPeg lexer.
+
+local lexer = lexer
+local P, S = lpeg.P, lpeg.S
+
+local lex = lexer.new(...)
+
+-- Keywords.
+lex:add_rule('keyword', lex:tag(lexer.KEYWORD, lex:word_match(lexer.KEYWORD)))
+
+-- Functions.
+local builtin_func = lex:tag(lexer.FUNCTION_BUILTIN, lex:word_match(lexer.FUNCTION_BUILTIN))
+lex:add_rule('function', -lpeg.B('.') * builtin_func * -S('.:|'))
+
+-- Identifiers.
+local word_char = lexer.alnum + S('_!?')
+local word = (lexer.alpha + '_') * word_char^0
+lex:add_rule('identifier', lex:tag(lexer.IDENTIFIER, word))
+
+-- Comments.
+local line_comment = lexer.to_eol('#', true)
+local block_comment = lexer.range(lexer.starts_line('=begin'), lexer.starts_line('=end'))
+lex:add_rule('comment', lex:tag(lexer.COMMENT, block_comment + line_comment))
+
+-- Strings.
+local delimiter_matches = {['('] = ')', ['['] = ']', ['{'] = '}'}
+local literal_delimited = P(function(input, index)
+  local delimiter = input:sub(index, index)
+  if not delimiter:find('[%w\r\n\f\t ]') then -- only non alpha-numerics
+    local match_pos, patt
+    if delimiter_matches[delimiter] then
+      -- Handle nested delimiter/matches in strings.
+      local s, e = delimiter, delimiter_matches[delimiter]
+      patt = lexer.range(s, e, false, true, true)
+    else
+      patt = lexer.range(delimiter)
+    end
+    match_pos = lpeg.match(patt, input, index)
+    return match_pos or #input + 1
+  end
+end)
+
+local cmd_str = lexer.range('`')
+local lit_cmd = '%x' * literal_delimited
+local lit_array = '%w' * literal_delimited
+local sq_str = lexer.range("'")
+local dq_str = lexer.range('"')
+local lit_str = '%' * S('qQ')^-1 * literal_delimited
+local heredoc = '<<' * P(function(input, index)
+  local s, e, indented, _, delimiter = input:find('([%-~]?)(["`]?)([%a_][%w_]*)%2[\n\r\f;]+', index)
+  if s == index and delimiter then
+    local end_heredoc = (#indented > 0 and '[\n\r\f]+ *' or '[\n\r\f]+')
+    s, e = input:find(end_heredoc .. delimiter, e)
+    return e and e + 1 or #input + 1
+  end
+end)
+local string = lex:tag(lexer.STRING, (sq_str + dq_str + lit_str + heredoc + cmd_str + lit_cmd +
+  lit_array) * S('f')^-1)
+-- TODO: regex_str fails with `obj.method /patt/` syntax.
+local regex_str = lexer.after_set('!%^&*([{-=+|:;,?<>~', lexer.range('/', true) * S('iomx')^0)
+local lit_regex = '%r' * literal_delimited * S('iomx')^0
+local regex = lex:tag(lexer.REGEX, regex_str + lit_regex)
+lex:add_rule('string', string + regex)
+
+-- Numbers.
+local numeric_literal = '?' * (lexer.any - lexer.space) * -word_char -- TODO: meta, control, etc.
+lex:add_rule('number', lex:tag(lexer.NUMBER, lexer.number_('_') * S('ri')^-1 + numeric_literal))
+
+-- Variables.
+local global_var = '$' *
+  (word + S('!@L+`\'=~/\\,.;<>_*"$?:') + lexer.digit + '-' * S('0FadiIKlpvw'))
+local class_var = '@@' * word
+local inst_var = '@' * word
+lex:add_rule('variable', lex:tag(lexer.VARIABLE, global_var + class_var + inst_var))
+
+-- Symbols.
+lex:add_rule('symbol', lex:tag(lexer.STRING .. '.symbol', ':' * P(function(input, index)
+  if input:sub(index - 2, index - 2) ~= ':' then return true end
+end) * (word_char^1 + sq_str + dq_str)))
+
+-- Operators.
+lex:add_rule('operator', lex:tag(lexer.OPERATOR, S('!%^&*()[]{}-=+/|:;.,?<>~')))
+
+-- Fold points.
+local function disambiguate(text, pos, line, s)
+  return line:sub(1, s - 1):match('^%s*$') and not text:sub(1, pos - 1):match('\\[ \t]*\r?\n$') and
+    1 or 0
+end
+lex:add_fold_point(lexer.KEYWORD, 'begin', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'class', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'def', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'do', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'for', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'module', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'case', 'end')
+lex:add_fold_point(lexer.KEYWORD, 'if', disambiguate)
+lex:add_fold_point(lexer.KEYWORD, 'while', disambiguate)
+lex:add_fold_point(lexer.KEYWORD, 'unless', disambiguate)
+lex:add_fold_point(lexer.KEYWORD, 'until', disambiguate)
+lex:add_fold_point(lexer.OPERATOR, '(', ')')
+lex:add_fold_point(lexer.OPERATOR, '[', ']')
+lex:add_fold_point(lexer.OPERATOR, '{', '}')
+lex:add_fold_point(lexer.COMMENT, '=begin', '=end')
+
+-- Word lists.
+lex:set_word_list(lexer.KEYWORD, {
+  'BEGIN', 'END', 'alias', 'and', 'begin', 'break', 'case', 'class', 'def', 'defined?', 'do',
+  'else', 'elsif', 'end', 'ensure', 'false', 'for', 'if', 'in', 'module', 'next', 'nil', 'not',
+  'or', 'redo', 'rescue', 'retry', 'return', 'self', 'super', 'then', 'true', 'undef', 'unless',
+  'until', 'when', 'while', 'yield', '__FILE__', '__LINE__'
+})
+
+lex:set_word_list(lexer.FUNCTION_BUILTIN, {
+  'at_exit', 'autoload', 'binding', 'caller', 'catch', 'chop', 'chop!', 'chomp', 'chomp!', 'eval',
+  'exec', 'exit', 'exit!', 'extend', 'fail', 'fork', 'format', 'gets', 'global_variables', 'gsub',
+  'gsub!', 'include', 'iterator?', 'lambda', 'load', 'local_variables', 'loop', 'module_function',
+  'open', 'p', 'print', 'printf', 'proc', 'putc', 'puts', 'raise', 'rand', 'readline', 'readlines',
+  'require', 'require_relative', 'select', 'sleep', 'split', 'sprintf', 'srand', 'sub', 'sub!',
+  'syscall', 'system', 'test', 'trace_var', 'trap', 'untrace_var'
+})
+
+lexer.property['scintillua.comment'] = '#'
+lexer.property['scintillua.word.chars'] =
+  'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_?!'
+
+return lex