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#ObjectScript

17

InterSystems ObjectScript is a scripting language to operate with data using any data model of InterSystems Data Platform (Objects, Relational, Key-Value, Document, Globals) and to develop business logic for serverside applications on InterSystems Data Platform.

Documentation.

On the back of my recent post on writing bug-less code I wanted to raise a few suggestions (to ISC) that would help prevent certain types of bugs at compile time. I've probably missed a few, but these are the main ones in my mind. Please contribute more suggestions.

Btw, these also serve as potential gotchas for new COS developers.

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I have classes A and B, B derived from A, A has method Abc.

From INT of class B I see that compiler copies implementation of Abc to class B, so that Abc exists both in A and B.

As result, when B invokes Abs, B.Abs() is executed instead of A.Abs(). In result debuger is not able to step into Abs and breakpoints in A.Abs never hit.

Why this happens and how can I avoid this?

Update:

OK, now I know the reason: compiler makes the copy if Abc has this line:

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With help from others here I had developed some code to take a Base64 PDF within a OBX.5 and save it locally to the file structure on the server.

I had to make a change to the code to return me a String so I can pass the Path back into Ensemble to use it in the message. When I made this change I am getting " ERROR #5034: Invalid status code structure ("/ensemble/data/transfer/AncillaryPDF/TMSAUDIO/Apr-11-1/980512729TMSAUDIO1046784936436537800.pdf")"

Here is the code...

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Hello, we have a few hundreds of triggers to port from Oracle to Cachè for a migration project, and many of them have to change (for example, normalize a value, null it, etc) the value which is being inserted.

The documentation says "You cannot set {fieldname*N} in trigger code." , so we're unlucky.

Is there a good workaround for this ?

SqlComputeOnChange doesn't seem the best way, but I'm not totally sure: for example normalization and validation could have a better place somewhere else than a trigger.

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What are the differences between a process private global and a percent variable? Basically I have some code running in an Ensemble operation that processes requests, and it needs access to pieces of data that are scattered throughout XData blocks in various classes. Rather than opening the XData object and deserializing the XML on each request, I opted to cache this data in a percent variable, something like:

set %MyVar(sub1,sub2) = myValue

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Question
· Mar 29, 2017
Count Number of Pages?

Hello,

We are working on creating a metadata file to accompany PDF documents produced by one of our third party systems for ingestion into our DMS. One of the pieces of data that the metadata file must contain is the number of pages of the PDF document.

In Cache ObjectScript does anybody know if there is currently a way of counting the number of pages within a file (specifically a PDF) without invoking a non-Caché ObjectScript program/function from within Caché ObjectScript?

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Article
· Mar 28, 2017 2m read
Map, Reduce and Filter Collections

Inspired by the article "Declarative development in Caché" that's still trending on the dev com. The OP explored a functional style of iterating over a collection. A comment today suggested "Caché would need syntax support for anonymous functions".

With Macros you can kind of get anonymous like syntax using dot notation.

This is not production code, but it does work. First the macros...

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Let's say I have two classes: A and B. They share no common parent except %SystemBase. But these classes have some properties with the same name (type may be the same or not):

Class A {

Property data As C;

Property data2;

}
Class B {

Property data As D;

Property data3;

}

I need to automatically convert object of class A into object of class B. I'm planing to write a class generator that generates a separate class that converts A to B. It would work like this:

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Hi,
I've organized my repository using TortoiseSVN. I was careful to use only svn commands while creating my file structure. Now all Subversion commands are working at the command line but not from within my IDE (Cache Studio). Basically I'm trying to write a plug-in for my IDE to use Subversion from within the Studio. Trying to integrate Subversion into my IDE, something like Subclipse, but for Cache Studio. The error occurred after reorganizing my code into directories. For example at the command-line, svn info and svn status and all other commands work perfectly. All Subversion commands work at the command prompt!

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Hi!

Consider I have a class Package.Data with Property UniqueStringValue as %String.

I introduced the Index for this property:

 Index ValueIndex on UniqueStringValue [Unique];

It works well. But if I try to check if there is an object with the certain value in code like this:

if ##class(Package.Data).ValueIndexExists(value)

this expression fails, if value="value", even if there is an instance with instance.UniqueStingValue="Value"

How can I set the index to prevent saving case sensitive values in this class?

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While I can see the benefits that $ZSTORAGE could have if used properly, I have not seen it used in the environments I have worked in. I was wondering if there are any developers that promote its usage.

If used properly, I would imagine it could be highly effective in maximizing free memory since some processes will never go over X amount, while others may very well need much more.

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If I were trying to access an index of a global variable, what time complexity would this operation have? My understanding of languages like Java/C++ is that arrays are stored as blocks of memory so that x[15] would have a lookup time complexity of O(1) because it just goes to (address of the array + 15) and retrieves the value stored there.

How does this work in Cache where the index of a variable isn't necessarily an integer value? If I were to have a variable like the following:

x("Adam") = "Red"

x("George") = "Blue"

x("Bryan") = "Green"

etc...

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I am in the planning stages of making things more uniform in our routines and I would like to know what the easiest way would be to include an .inc at the beginning of each .mac routine. Has anyone written something that would open all routines and place something into the first row while leaving the rest of the routine unchanged? Thanks for any guidance you all may provide.

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