diff options
| -rw-r--r-- | hyperquirks.lisp | 18 | ||||
| -rw-r--r-- | package.lisp | 1 |
2 files changed, 18 insertions, 1 deletions
diff --git a/hyperquirks.lisp b/hyperquirks.lisp index d64ce08..7b6da14 100644 --- a/hyperquirks.lisp +++ b/hyperquirks.lisp @@ -150,7 +150,18 @@ form. When they do, the value of the previous form is passed into all instances is substituted in. However, two different substitution variables CANNOT APPEAR in a -single pipe form." +single pipe form. + +This macro accepts additional syntax: the :? form standing on its own +indicates the the next form shold be a predicate that, if it evaluates +to NIL, causes an early exit, with failure state FAIL. + +E.g. + +(>> (:fail :oh-no!) + (random 10) ; start with a random number + :? evenp ; exit with :oh-no! unless even + (+ 10 _)) ; add 10 and return." (let ((prefix (etypecase prefix (string prefix) @@ -158,6 +169,7 @@ single pipe form." (labels ((var-p (v) "A variable is a symbol that starts with PREFIX" (and (symbolp v) + (<= (length prefix) (length (symbol-name v))) (string= prefix (symbol-name v) :end2 (length prefix)))) (pipe-form-p (form) "A pipe form is either a symbol or a tree that contains @@ -211,6 +223,10 @@ single pipe form." (list 'block block (reduce #'folder (escape-early-transform pipe-forms) :initial-value initform))))) + +(defmacro >>> (initform &rest pipe-forms) + `(>> () ,initform ,@pipe-forms)) + (defmacro binding-cond (&body clauses) "Like cond except the first form of every clause is a binding form alá IMPERATIVE. diff --git a/package.lisp b/package.lisp index 5025869..141b53e 100644 --- a/package.lisp +++ b/package.lisp @@ -6,6 +6,7 @@ (:export #:with-env #:>> + #:>>> #:let+ #:imperative #:binding-cond |