5Module Lexer🔗 i

• The module-lexer function accepts an offset and lexer mode, instead of just an input port.

• In addition to the results of racket-lexer , module-lexer returns a backup distance and a new lexer mode.

• When mode is #f (indicating the start of the stream), the lexer checks in for a #lang specification.

  If a #lang line is present but the specified language does not exist, the entire in input is consumed and colored as 'error.

  If the language exists and the language provides a get-info function, then it is called with 'color-lexer. If the result is not #f, then it should be a lexer function for use with color:text<%> . The result mode is the lexer—paired with #f if the lexer is a procedure arity 3—so that future calls will dispatch to the language-supplied lexer.

  If the language is specified but it provides no get-info or 'color-lexer result, then racket-lexer is returned as the mode.

• When mode is a lexer procedure, the lexer is applied to in. The lexer’s results are returned, plus the lexer again as the mode; if the lexer produces a hash-table attribute result, however, the 'type value is extracted and returned in place of the hash table.

• When mode is a pair, then the lexer procedure in the car is applied to in, offset, and the mode in the cdr . The lexer’s results are returned, except that its mode result is paired back with the lexer procedure.

Added in version 1.2 of package syntax-color-lib.