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lexer/  c
lexer*/  c
dont-stop
check-colorer-results-match-port-before-and-afters

2 Lexer Contract and The Don’t-Stop Structure Type

 (require syntax-color/lexer-contract)
  package: syntax-color-lib

Checks to be sure a lexing function is well-behaved, constrained to functions where the second return value is a symbol. For more details, see start-colorer in color:text<%>.

Checks to be sure a lexing function is well-behaved. For more details, see start-colorer in color:text<%>.

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

struct

(struct dont-stop (val))

  val : any/c
A structure type used to indicate to the lexer that it should not allow itself to be interrupted. For more details, see start-colorer in color:text<%>.

procedure

(check-colorer-results-match-port-before-and-afters 
  who 
  type 
  pos-before 
  new-token-start 
  new-token-end 
  pos-after) 
  void?
  who : symbol?
  type : any/c
  pos-before : (or/c exact-positive-integer? #f)
  new-token-start : (or/c exact-positive-integer? #f)
  new-token-end : (or/c exact-positive-integer? #f)
  pos-after : (or/c exact-positive-integer? #f)
Checks that the results of a colorer make sense with respect to the positions of the port, before and after the lexer is called.

The pos-before argument is expected to be the third result of port-next-location before a lexer is called and the pos-after argument is expected to to be the third result of port-next-location after the lexer is called. The type, token-start, and token-end arguments should be the corresponding results from the colorer (c.f. start-colorer).

This function raises an error unless the following boolean expression is true:
(or (equal? type 'eof)
    (and (<= pos-before new-token-start pos-after)
         (<= pos-before new-token-end pos-after)))
but it checks the individual parts of the expression to raise a more meaningful error message when some part is not true.

The who argument is used to start the error message.

Added in version 1.4 of package syntax-color-lib.