values lib

1 files changed, 54 insertions, 0 deletions

diff --git a/doc/mcgoron.cond-thunk.values.scm b/doc/mcgoron.cond-thunk.values.scm
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+(((name . "after")
+  (signature syntax-rules (when let =>) (after (clause ...) body ...))
+  (subsigs
+   (clause (pattern
+            ((when conditional))
+            ((let value => formal)))))
+  (desc "
+For each clause,
+
+* If `clause` is `when conditional`, then `conditional` is evaluated. If
+  `conditional` is false, then the `after` expression returns `#f`.
+  Otherwise the rest of the clauses are executed.
+* If `clause` is `let value => formal`, then `value` is evaluated. If
+  `value` returns no values, then the `after` expression returns `#f`.
+  Otherwise, the values returned are bound to `formal` in the next clauses
+  and in the body.
+
+Once all clauses succeed, the `after` clause returns a thunk containing
+body. The free variables bound in and surrounding the `after` expression
+are captured in the thunk."))
+ ((name . "cond-values")
+  (signature syntax-rules () (cond-values clauses ...))
+  (desc "
+A wrapper around `cond-thunk` that returns no values instead of `#f`
+when all clauses are exhausted. This is intended for destructuring
+procedures used by `after`. See `cond-thunk` for more details."))
+ ((name . "pair=>")
+  (signature lambda (x) => (or (values * *) (values)))
+  (tags destructuring)
+  (desc "
+If `x` is a pair, return its car and cdr. Otherwise return no values."))
+ ((name . "length-at-least=>")
+  (signature lambda (whole-list (integer? num)) *)
+  (tags destructuring)
+  (desc "
+* It is an error if `num` is not a positive integer.
+
+If `whole-list` is a proper or improper list of length at least `num`,
+then `num + 1` values are delivered: the first `num` elements and a
+final element with the rest of the list."))
+ ((name. "length=>")
+  (signature lambda (whole-list (integer? num)) *)
+  (tags destructuring)
+  (desc "
+* It is an error if `num` is not a positive integer.
+
+If `whole-list` is a proper list of length `num`, then each element of the
+list is returned as values."))
+ ((name . "apply-after")
+  (signature syntax-rules () ((_ producer consumer)))
+  (desc "
+Evaluates `producer`. If `producer` evaluates to at least one value, then
+return a thunk that, when called, tail-calls `consumer` with the values
+that `producer` produced. Otherwise, return `#f~.")))
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