ObjectScript

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This post is intended to guide you through the new JSON capabilities that we introduced in Caché 2016.1. JSON has emerged to a serialization format used in many places. The web started it, but nowadays it is utilized everywhere. We've got plenty to cover, so let's get started.

Last comment 11 January 2019
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Hi Community!

Coding guidelines discussion. Consider you have For with one command in the cycle. Here are the options:

One

For i=1:1:1000 set ^Test(i)=""

Two

For i=1:1:1000 {
 set ^Test(i)=""
}

Same for the "If":

if a set b=a

or

if a {
 set b=a
}

Your choice? Or maybe even other options? 

Last comment 23 October 2019
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Hi, Community!

Have a question for general discussion. 

In ObjectScript we have cls for classes and mac code, which both compile into int code. 

Is there any reason when you use mac instead of cls  for non-persistent classes?

For me the benefits for cls are:

1. Inheritance and other OOP features

2. Auto-documented code 

For mac one visible benefit is easier call in terminal:

do method^Utils(p1,p2)

vs

Last comment 18 July 2018
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Hi Everyone!

As you know Advent of Code 2018 is in full swing! Till the 25th of December 2018 each day 2 programming problems to sharpen your programming skills! 

And now we're ready to present great prizes for Members of InterSystems Global Masters Advocate Hub!

Last comment 2 January 2019
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Hello Everyone,

I'm want to know, what is more common for your company to use, the abbreviation syntax or the complety name of commands, and why?

Ex. 

S VAR=10 / D FUNC^ROUTINE F 1:1:1000

Set VAR=10 / Do Func^Routine / For 1:1:1000

set var=10 / do func^routine / for 1:1:1000

Here in my company, we are familiar with the abbreviation syntax, because to spell is more faster.

Last answer 29 October 2019 Last comment 20 November 2019
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Hello!

This article is a small overview of a tool that helps to understand classes and their structure inside the InterSystems products: from IRIS to Caché, Ensemble, HealthShare.

In short, it visualizes a class or an entire package, shows the relations between classes and provides all the possible information to developers and team leads without making them go to Studio and examine the code there.

If you are learning InterSystems products, reviewing projects a lot or just interested in something new in InterSystems Technology solutions — you are more than welcome to read the overview of ObjectScript Class Explorer!

Last comment 19 July 2019
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Greetings, InterSystems community!

I am pleased to announce that the web terminal project, Caché WebTerminal version 4 gets its release! After long period of enhancing this web application from 2013, it came to the version 4, which features major stability and security improvements, intelligent autocomplete and syntax highlighting, convenient SQL mode and a lot of other useful features.

The goal of this article is to spread the knowledge about this project over the InterSystems community.

Last comment 26 February 2019
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The DeclarativeCOS project is a heartfelt cry about programming in the COS language.

The purpose of the project is to draw attention of the public to improving the inner core of COS.

The idea of the project is the support of a laconic syntax for cycles and collections.

So what is this laconic something that I have come up with? Welcome to the examples below!

Examples

The key concept underlying the project is the declarative approach to writing code. You need to specify WHAT should be used and HOW.

Last comment 3 September 2019
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SOLVED

tl;dr how can you tell if a number is really a string

The original question has been updated/improved.

Equality comparisons on floating point numbers will produce different results...

"1.1"=1.1  //is true!

"0.1"=0.1  //is not true :(

This second comparison can be fixed with...

+"0.1"=+0.1 // is true!

Last answer 31 August 2017 Last comment 1 September 2017
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Hi Community!

Sometimes I meet a method which accepts 10+ parameters.

And often I need only the 8th parameter  to  pass. And I call the method something like:

do ##class(Some.Feature).Method(,,,,,,,"flag")

And I don't like this method when I call it like this cause, you know, often I just miss the number of commas and raise some other flag I wanted.

How do you avoid this situations? 

If you meet such a code, how do you call it and sure that you didn't miss the number of ","?

What is a good number of parameters in a method and f you need to pass more parameters in a method what do you do?

Last answer 5 May 2019 Last comment 27 August 2019
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Hi, folks!

Suppose you have a Caché class with %String property which contains relatively large text (from 10 to 2000 symbols).

The class:

Class Test.Duplicates Extends %Persistent 

{

Property Text As %String (MAXLEN = 2000);

}

And you have thousands of entries.

What are the best options to find entries which are duplicates on this property?

Last answer 1 December 2017 Last comment 9 November 2017
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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.

Last comment 18 April 2017
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Hi!

Want to share with you code snippet of try catch block I usually use in methods which should return %Status. 


{ 
 try {
  	$$$TOE(sc,StatusMethod())
 }
 catch e {
 	set sc=e.AsStatus()
 	do e.Log()
 }

Quit sc 
}

Here $$$TOE is a short form of $$$TROWONERROR macro.

Inside macro StatusMethod is any method you call which will return %Status value. This value will be placed into sc variable.

Last comment 9 May 2016
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The topic of for/while loop performance in Caché ObjectScript came up in discussion recently, and I'd like to share some thoughts/best practices with the rest of the community. While this is a basic topic in itself, it's easy to overlook the performance implications of otherwise-reasonable approaches.

Last comment 12 July 2019
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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:

Last answer 12 April 2017 Last comment 12 April 2017
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Caché offers a number of methods for going through a collection and doing something with its elements. The easiest method uses a while-loop and lets you fulfill the task in an imperative manner. The developer needs to take care of the iterator, jumping to the next element and checking if the loop is within the collection.

Last comment 4 July 2017
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Hi guys!

As you know there are two (at least) ways to get the stored value of the property of InterSystems IRIS class if you know the ID of an instance (or a record).

1. Get it by as a property of an instance with "Object access":

ClassMethod GetPropertyForID(stId As %Integer) As %String

{

set obj=..%OpenId(stId)

return obj.StringData

}

2. Get it as a value of a column of the record with "SQL access":

Last answer 29 June 2019 Last comment 6 July 2019
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I am trying to determine the write-access to a windows-directory, using the method %File.Writeable(). But, this method always returns the boolean "true", even when I have revoked the write-access of Healthshare-user in this directory.

Note:
1) When the same ensemble-service tries to write a file in this directory (which it says is "writeable"), it fails.
2) The method %File.Writeable(...) works perfectly in the case of files.

Any help is appreciated.
Thanks in advance... :-)

Last answer 6 February 2018 Last comment 8 February 2018
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Hello!

In Caché there is a way to print all current variables using write command without arguments:

USER>set Einstein = 1879
USER>set Mozart = 1756
USER>write
Einstein=1879
Mozart=1756

But is there a way to get a list of this variables? I am looking for something that would return value like $LB("Einstein", "Mozart") for this case.

Thanks!

Last answer 30 June 2016 Last comment 30 June 2016
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Hello,

I have some beginner questions as I am working through the InterSystems Cache learning path:

- Where I work, we us Cache, but we often learning about and train on MUMPS.  No one really talks about or mentions MUMPS here, but my understanding is that ObjectScript is basically MUMPS plus whatever new things InterSystems put on top of it.  Is that a fair assessment?

Last answer 4 January 2019 Last comment 4 January 2019
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Hello guys,

I've got this piece of code which runs the method "WebMethod", that belongs to %SOAP.WebBase.cls.

It grabs the outcome from an internal webservice we have and after that, it writes into a file.

The thing is, when I browse the file contents, I realize that in the place where a special character should be, I see a question mark.

By querying the same webservice from a special soap tool called "SoapSonar" (I've been using this for years), the outcome shows up this special character (shows it properly).

Last answer 31 January 2017 Last comment 2 February 2017
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Forgive my lack of understanding, but I am working on a vendor created Cache database and the indexes specified in the classes for ODBC connections are not working. A few of them are created, but of the 50+ classes we have, only a handful of them are created when the class is compiled, yet no errors occur.

Example 1:

 

Example 2:

 

Last answer 31 May 2019 Last comment 18 June 2019
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I'm pleased to announce the latest version of the renewed for ObjectScript, which is now available with a lot of new features.

This new extension is a fork of previously developed extension in different repository originally started by @Oleg Dmitrovich.

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