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<%>.
It also supplies a few random arguments to the lexer and checks the results, using option/c’s #:tester argument.
Added in version 1.2 of package syntax-color-lib.
The same contract as lexer*/c, except without the random testing.
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) (< new-token-start new-token-end) (= 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.