File: NOTE-2-7-GUARDS.html

package info (click to toggle)
acl2 3.1-1
  • links: PTS
  • area: main
  • in suites: etch, etch-m68k
  • size: 36,712 kB
  • ctags: 38,396
  • sloc: lisp: 464,023; makefile: 5,470; sh: 86; csh: 47; cpp: 25; ansic: 22
file content (39 lines) | stat: -rw-r--r-- 1,129 bytes parent folder | download 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
 
<html>
<head><title>NOTE-2-7-GUARDS.html  --  ACL2 Version 3.1</title></head>
<body text=#000000 bgcolor="#FFFFFF">
<h3>NOTE-2-7-GUARDS</h3>ACL2 Version  2.7 Notes on Guard-related Changes
<pre>Major Section:  <a href="NOTE-2-7.html">NOTE-2-7</a>
</pre><p>

It was possible for guard verification to succeed where it should have
failed.  See the discussion under <a href="NOTE-2-7-BUG-FIXES.html">note-2-7-bug-fixes</a>.<p>

There have been changes in the guards generated from type declarations for
the following cases.  Thanks to Dave Greve and Matt Wilding for suggesting
such changes.

<pre>
(type (signed-byte n) val)
(type (unsigned-byte n) val)
(type (integer m n) val)
</pre>

The following examples illustrate the changes.

<pre>
(type (signed-byte 4) x)
==&gt; [old] (AND (INTEGERP X) (&lt;= -8 X) (&lt;= X 7))
==&gt; [new] (SIGNED-BYTE-P 4 X)<p>

(type (unsigned-byte 4) x)
==&gt; [old] (AND (INTEGERP X) (&lt;= 0 X) (&lt;= X 15))
==&gt; [new] (UNSIGNED-BYTE-P 4 X)
</pre>
<p>


<p>

<br><br><br><a href="acl2-doc.html"><img src="llogo.gif"></a> <a href="acl2-doc-index.html"><img src="index.gif"></a>
</body>
</html>