# The only difficulty is to distinguish: `fn(argument)` from `fn (sequence)`. # The presence of the whitespace determines if it is an argument to the # function call `fn` or if a sequence follows the function call. # # If there is the potential for an argument list, the lexer enters the state `:ARG`. # The rest of the times, the state is `nil`. # # In case of an argument list, :tARG_LIST is emitted instead of a '('. # Therefore, the token '(' always signals the beginning of a sequence.

class RuboCop::AST::NodePattern::LexerRex

macros

CONST_NAME                /[A-Z:][a-zA-Z_:]+/
SYMBOL_NAME               /[\w+@*\/?!<>=~|%^&-]+|\[\]=?/
IDENTIFIER                /[a-z][a-zA-Z0-9_]*/
NODE_TYPE                 /[a-z][a-zA-Z0-9_-]*/  # Same as identifier but allows '-'
CALL                      /(?:#{CONST_NAME}\.)?#{IDENTIFIER}[!?]?/
REGEXP_BODY               /(?:[^\/]|\\\/)*/
REGEXP                    /\/(#{REGEXP_BODY})(?<!\\)\/([imxo]*)/

rules

      /\s+/
      /:(#{SYMBOL_NAME})/o      { emit :tSYMBOL, &:to_sym }
      /"(.+?)"/                 { emit :tSTRING }
      /[-+]?\d+\.\d+/           { emit :tNUMBER, &:to_f }
      /[-+]?\d+/                { emit :tNUMBER, &:to_i }
      /#{Regexp.union(
        %w"( ) { | } [ ] < > $ ! ^ ` ... + * ? ,"
      )}/o                      { emit ss.matched, &:to_sym }
      /#{REGEXP}/o              { emit_regexp }
      /%?(#{CONST_NAME})/o      { emit :tPARAM_CONST }
      /%([a-z_]+)/              { emit :tPARAM_NAMED }
      /%(\d*)/                  { emit(:tPARAM_NUMBER) { |s| s.empty? ? 1 : s.to_i } } # Map `%` to `%1`
      /_(#{IDENTIFIER})/o       { emit :tUNIFY }
      /_/o                      { emit :tWILDCARD }
      /\#(#{CALL})/o            { @state = :ARG; emit :tFUNCTION_CALL, &:to_sym }
      /#{IDENTIFIER}\?/o        { @state = :ARG; emit :tPREDICATE, &:to_sym }
      /#{NODE_TYPE}/o           { emit :tNODE_TYPE, &:to_sym }
:ARG  /\(/                      { @state = nil; emit :tARG_LIST }
:ARG  //                        { @state = nil }
      /\#.*/                    { emit_comment }

end