commit a660fdb3a001a98f7d647bc3b340deb99e92a91a
parent 9af1e49fb2f797f2963588d89e4ca7923f8320fd
Author: Taylan Ulrich Bayırlı/Kammer <taylanbayirli@gmail.com>
Date: Thu, 3 Sep 2015 13:18:45 +0200
Don't discriminate unsafe Scheme implementations.
Diffstat:
2 files changed, 19 insertions(+), 19 deletions(-)
diff --git a/srfi-123.html b/srfi-123.html
@@ -44,7 +44,7 @@ struct ;=> #(a (x y #u8(4 2 3)) c)</code></pre>
(ref table "foo" 'not-found) ;=> not-found
(set! (~ table "foo") "Foobar.")
(ref table "foo" 'not-found) ;=> "Foobar."</code></pre>
-<p>Lack of a default argument raises an error in this case. Since <code>ref*</code> cannot take default arguments for any fields it accesses, it always raises an error when a hashtable key in the chain is not found.</p>
+<p>Lack of a default argument is an error in this case. Since <code>ref*</code> cannot take default arguments for any fields it accesses, it is an error when a hashtable key in the chain is not found.</p>
<pre><code>(define table (make-eqv-hashtable))
(define lst (list 0 1 table 3))
(ref* lst 2 "foo" 'x) ;error while accessing "foo" from table</code></pre>
@@ -83,19 +83,18 @@ struct ;=> #(a (x y #u8(4 2 3)) c)</code></pre>
{vec[1] + vec[2]} ;=> 5</code></pre>
<p>The square brackets accept a chain of fields, since they have the semantics of <code>ref*</code>: <code>{matrix[i j]}</code>.</p>
<h2 id="specification">Specification</h2>
+<p>Within this section, whenever a situation is described as being an error, a Scheme implementation supporting error signaling should signal an error.</p>
<ul>
<li><code>(ref object field)</code> (procedure)</li>
<li><code>(ref object field default)</code></li>
</ul>
-<p>Returns the value for <code>field</code> in <code>object</code>. An error is raised if <code>object</code> has no field identified by <code>field</code>. (This error will often come from the underlying accessor procedure.)</p>
+<p>Returns the value for <code>field</code> in <code>object</code>. It is an error if <code>object</code> has no field identified by <code>field</code>.</p>
<pre><code>(ref #(0 1 2) 3) ;error: vector-ref: Index out of bounds.</code></pre>
-<p>If <code>object</code> is of a "sparse" type, meaning its fields can be "empty" or "unassigned" (e.g. a hashtable), and the requested field is empty, then the value of <code>default</code> is returned if given, and otherwise an error raised.</p>
+<p>If <code>object</code> is of a "sparse" type, meaning its fields can be "empty" or "unassigned" (e.g. a hashtable), and the requested field is empty, then the value of <code>default</code> is returned. It is an error if the <code>default</code> argument is not provided in this case.</p>
<pre><code>(ref hashtable unassigned-key 'default) ;=> default
(ref hashtable unassigned-key) ;error</code></pre>
-<p>If <code>object</code> is not of a sparse type, then passing <code>default</code> is an error.</p>
-<pre><code>(ref '(0 1 2) 3 'default) ;error: list-ref: Too many arguments.
- ;Unless the implementation's list-ref
- ;does something else.</code></pre>
+<p>If <code>object</code> is not of a sparse type, then providing the <code>default</code> argument is an error.</p>
+<pre><code>(ref '(0 1 2) 3 'default) ;error: list-ref: Too many arguments.</code></pre>
<p>Valid types for <code>object</code> are: bytevectors, hashtables, pairs, strings, vectors, non-opaque record types, and SRFI-4 vectors if present. Only hashtables are a sparse type. Implementations are encouraged to expand this list of types with any further types they support.</p>
<p>Valid types for <code>field</code> depend on the type of <code>object</code>. For bytevectors, hashtables, strings, vectors, and SRFI-4 vectors, refer to their respective <code>*-ref</code> procedures. For pairs, refer to <code>list-ref</code>. For records, symbols that correspond with the record type's field names are allowed.</p>
<p>A conforming implementation must be prepared for SRFI-4 vector types and bytevectors not being disjoint types, and treat SRFI-4 vectors suitably and not as regular bytevectors.</p>
diff --git a/srfi-123.md b/srfi-123.md
@@ -76,9 +76,9 @@ argument for objects such as hashtables.
(set! (~ table "foo") "Foobar.")
(ref table "foo" 'not-found) ;=> "Foobar."
-Lack of a default argument raises an error in this case. Since `ref*`
-cannot take default arguments for any fields it accesses, it always
-raises an error when a hashtable key in the chain is not found.
+Lack of a default argument is an error in this case. Since `ref*`
+cannot take default arguments for any fields it accesses, it is an
+error when a hashtable key in the chain is not found.
(define table (make-eqv-hashtable))
(define lst (list 0 1 table 3))
@@ -180,29 +180,30 @@ semantics of `ref*`: `{matrix[i j]}`.
Specification
-------------
+Within this section, whenever a situation is described as being an
+error, a Scheme implementation supporting error signaling should
+signal an error.
+
- `(ref object field)` (procedure)
- `(ref object field default)`
-Returns the value for `field` in `object`. An error is raised if
-`object` has no field identified by `field`. (This error will often
-come from the underlying accessor procedure.)
+Returns the value for `field` in `object`. It is an error if `object`
+has no field identified by `field`.
(ref #(0 1 2) 3) ;error: vector-ref: Index out of bounds.
If `object` is of a "sparse" type, meaning its fields can be "empty"
or "unassigned" (e.g. a hashtable), and the requested field is empty,
-then the value of `default` is returned if given, and otherwise an
-error raised.
+then the value of `default` is returned. It is an error if the
+`default` argument is not provided in this case.
(ref hashtable unassigned-key 'default) ;=> default
(ref hashtable unassigned-key) ;error
-If `object` is not of a sparse type, then passing `default` is an
-error.
+If `object` is not of a sparse type, then providing the `default`
+argument is an error.
(ref '(0 1 2) 3 'default) ;error: list-ref: Too many arguments.
- ;Unless the implementation's list-ref
- ;does something else.
Valid types for `object` are: bytevectors, hashtables, pairs, strings,
vectors, non-opaque record types, and SRFI-4 vectors if present. Only
