diff options
| author | 2021-12-29 19:22:00 +0100 | |
|---|---|---|
| committer | 2021-12-29 19:22:00 +0100 | |
| commit | b0431e3249640014c05cdec3450ea0737295e8d8 (patch) | |
| tree | 75e27537703dacb0ba953ac02763d18212f14391 | |
| parent | Add missing space (diff) | |
Issue: type-test argument to make-product-comparator may be unneeded
| -rw-r--r-- | srfi-228.html | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/srfi-228.html b/srfi-228.html index 407a279..6386904 100644 --- a/srfi-228.html +++ b/srfi-228.html @@ -53,6 +53,7 @@ <dt><code>(make-product-comparator</code> <var>type-test</var> <var>comparator</var> ... <code>)</code> (Procedure) <dd> <p>Returns a comparator which compares values satisfying the given predicate <var>type-test</var> by comparing them with each of the given comparators in turn, left to right, and returning the result of the first non-equal comparison. If all the given comparators consider two values equal, the product comparator also considers them equal. The hash function of the product comparator hashes together the results of all the given comparators in an implementation-defined way. If the equality or ordering predicates or the hash function of any of the given comparators is <code>#f</code>, the corresponding procedure in the product comparator will also be <code>#f</code>.</p> + <p class=issue>Is the <var>type-test</var> argument needed? It could easily be defined by <code>(lambda (x) (every (lambda (cmp) ((comparator-type-test cmp) x)) comparators))</code>, by analogy to <code>make-sum-comparator</code>. <p class=issue>Add example.</p> <dt><code>(make-sum-comparator</code> <var>comparator</var> ... <code>)</code> (Procedure) |
