This issue was discussed a bit back in August. A readonly verb in the jmf
script allows toggling the readonly state of a mapping. Please study the
copied messages below. This is also covered in the lab. I think this is an
adequate solution to the problem. If it isn't please clarify.
Map your files as readonly and toggle them carefully as required for
updates.
***
Eric Iverson to Beta forum August-31-06
I haven't studied the problem and only did what could be done trivially
with exisiting mechanisms. Note:
map_jmf_ 'jdata';jdatafn
1 readonly_jmf_ 'jdata'
jdata
123
jdata=:23
|read-only data
| jdata =:23
abc=:jdata
abc=:23
|read-only data
| abc =:23
----- Original Message -----
From: "Joey K Tuttle" <[EMAIL PROTECTED]>
To: "Beta forum" <[email protected]>
Sent: Thursday, August 31, 2006 6:52 PM
Subject: Re: [Jbeta] win and win64 w betas available
Now if you could be convinced to make any aliases of
the mapped name be readonly (or at least readonly by
default) I would be much happier....
- joey
At 18:32 -0400 2006/08/31, Eric Iverson wrote:
The w beta for win and win64 is available.
Please get these through the web site and take a look at the new
installation instructions.
This beta includes a minor addition to mapped files (jmf.ijs) and the
mapped file lab (steps 51,52,53). Verb readonly is defined to turn the
readonly attribute of a name off and on. This can be used to provide
additional protection from errors that cause nasty damage. If a file is
mapped readonly then it can't be damaged, but it also can't be updated.
The use of readonly can restrict updates to specific parts of an
application and protect against some kinds of damage from errors.
map file to noun data (not readonly)
1 readonly_jmf_ 'data' NB. file is read/write, but immediately mark noun
as readonly
data=: 'ooops' NB. gets an error and damage is avoided
0 readonly_jmf_ 'data' NB. allow update
do the carefully coded update
1 readonly_jmf_ 'data' NB. protect the data from unintended changes
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