diff --git a/main.rkt b/main.rkt index 601b384..53fcca4 100644 --- a/main.rkt +++ b/main.rkt @@ -346,6 +346,18 @@ (error 'splitf-txexpr "Bad input")) (reverse matches))) +(define+provide+safe (findf*-txexpr tx pred) + (txexpr? procedure? . -> . (or/c #f txexpr-elements?)) + (define-values (_ matches) (splitf-txexpr tx pred)) + (and (pair? matches) matches)) + + +(define+provide+safe (findf-txexpr tx pred) + (txexpr? procedure? . -> . (or/c #f txexpr-element?)) + (define matches (findf*-txexpr tx pred)) + (and matches (car matches))) + + (define+provide+safe (xexpr->html x) (xexpr? . -> . string?) (define (->cdata x) diff --git a/scribblings/txexpr.scrbl b/scribblings/txexpr.scrbl index f8f9dc3..1d5f249 100644 --- a/scribblings/txexpr.scrbl +++ b/scribblings/txexpr.scrbl @@ -525,6 +525,33 @@ Ordinarily, the result of the split operation is to remove the elements that mat ] +@deftogether[( +@defproc[ +(findf*-txexpr +[tx txexpr?] +[pred procedure?]) +(or/c #f (listof txexpr-element?))] + +@defproc[ +(findf-txexpr +[tx txexpr?] +[pred procedure?]) +(or/c #f txexpr-element?)] +)] +Like @racket[splitf-txexpr], but only retrieve the elements that match @racket[_pred]. @racket[findf*-txexpr] retrieves all results; @racket[findf-txexpr] only the first. In both cases, if there are no matches, you get @racket[#f]. + +@examples[#:eval my-eval +(define tx '(div "Wonderful day" (meta "weather" "good") + "for a walk" (meta "dog" "Roxy"))) +(define is-meta? (λ(x) (and (txexpr? x) (eq? 'meta (get-tag x))))) +(findf*-txexpr tx is-meta?) +(findf-txexpr tx is-meta?) +(define is-zimzam? (λ(x) (and (txexpr? x) (eq? 'zimzam (get-tag x))))) +(findf*-txexpr tx is-zimzam?) +(findf-txexpr tx is-zimzam?) +] + + @defproc[ (check-txexprs-equal? [tx1 txexpr?] diff --git a/tests.rkt b/tests.rkt index 91ad340..e3e7f32 100644 --- a/tests.rkt +++ b/tests.rkt @@ -196,13 +196,19 @@ (define split-this-tx '(root (meta "foo" "bar") "hello" "world" (meta "foo2" "bar2") (em "goodnight" "moon" (meta "foo3" "bar3")))) - (define split-predicate (λ(x) (and (txexpr? x) (equal? 'meta (car x))))) + (define split-predicate (λ(x) (and (txexpr? x) (eq? 'meta (get-tag x))))) (check-txexprs-equal? (call-with-values (λ() (splitf-txexpr split-this-tx split-predicate)) list) (list '(root "hello" "world" (em "goodnight" "moon")) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3")))) (define split-proc (λ(x) '(div "foo"))) (check-txexprs-equal? (call-with-values (λ() (splitf-txexpr split-this-tx split-predicate split-proc)) list) (list '(root (div "foo") "hello" "world" (div "foo") (em "goodnight" "moon" (div "foo"))) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3")))) + + (define false-pred (λ(x) (and (txexpr? x) (eq? 'nonexistent-tag (get-tag x))))) + (check-equal? (findf*-txexpr split-this-tx split-predicate) '((meta "foo" "bar") (meta "foo2" "bar2") (meta "foo3" "bar3"))) + (check-false (findf*-txexpr split-this-tx false-pred)) + (check-equal? (findf-txexpr split-this-tx split-predicate) '(meta "foo" "bar")) + (check-false (findf-txexpr split-this-tx false-pred)) (check-equal? (xexpr->html '(root (script "3 > 2") "Why is 3 > 2?")) "Why is 3 > 2?")) \ No newline at end of file