7 Conditionals
procedure
(rx/conditional test if-true [if-false]) → string?
test : string? if-true : string? if-false : (or/c string? #f) = #f
procedure
test : string? if-true : string? if-false : (or/c string? #f) = #f
TBD
Example:
> '() '()
procedure
(rx/look-ahead expr) → string?
expr : string?
procedure
expr : string?
TBD
Example:
> '() '()
procedure
(rx/not-look-ahead expr) → string?
expr : string?
procedure
expr : string?
TBD
Example:
> '() '()
procedure
(rx/look-behind expr) → string?
expr : string?
procedure
expr : string?
TBD
Example:
> '() '()
procedure
(rx/not-look-behind expr) → string?
expr : string?
procedure
expr : string?
TBD
Example:
> '() '()
procedure
(rx/group-ref n) → string?
n : integer?
TBD
The type of n depends on the parameter rx/has-relative-group-refs; if #t the type allows negative and positive values, otherwise it only allows positive.
The form of a group reference depends on the value of the parameter rx/group-ref-form.
Examples:
> (parameterize ((rx/group-ref-form 'grouped)) (rx/group-ref 1)) "(1)"
> (parameterize ((rx/group-ref-form 'escaped)) (rx/group-ref 1)) "\\1"
> (parameterize ((rx/group-ref-form 'grouped)) (rx/conditional (rx/group-ref 1) "-bird" "bird")) "(?(1)-bird|bird)"
> (parameterize ((rx/group-ref-form 'escaped)) (rx/conditional (rx/group-ref 1) "-bird" "bird")) "(?\\1-bird|bird)"