This is a series of programming challenges for beginners and experienced Caché programmers.

For an introduction : goto to article

The challenge of day 5 is to calculate a password of 8 characters by finding the MD5 hash of the input and an increasing integer index.
The password is constructed by taking the 6th character of the first 8 hashes that start with 5 zeroes (in hex representation).

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First-class functionwiki

In computer science, a programming language is said to have first-class functions if it treats functions as first-class citizens. This means the language supports passing functions as arguments to other functions, returning them as the values from other functions, and assigning them to variables or storing them in data structures. Some programming language theorists require support for anonymous functions (function literals) as well. In languages with first-class functions, the names of functions do not have any special status; they are treated like ordinary variables with a function type.

This post continues the article “Declarative development in Caché”.

[2, 3, 5, 7, 11, 13, 17].forEach(function(i) {

How to do something like this in Caché using COS?

Below are some exercises on this topic.

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· Jul 1, 2019 2m read
Transaction suspencion

It’s often useful to make changes inside the current transaction, that would not be rolled-back if transaction is rolled-back. For example to do some logging.

This can be achieved by using global that is mapped to temporary database -- IRISTEMP. All globals that start with ^IRIS.Temp* are mapped to IRISTEMP by default. Problem with such approach is that IRISTEMP is cleaned on InterSystems IRIS restart, so this log is lost.

What else you can do is -- suspend transaction temporarily, do the logging, and then resume the same transaction.

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· Jul 19, 2022 4m read
Caution with Mixing OO and SQL

Mixing Object syntax with SQL is one of the nice features in Object Script. But in one case, it gave strange results, so I decided to isolate the case and describe it here.

Let's say you need to write a classmethod that updates a single property on disk. Usually, i would write that using SQL like this :

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This is a series of programming challenges for beginners and experienced Caché programmers.

For an introduction : go to article

Today's challenge is about decompressing input that is compressed in an experimental format.
In the format, markers indicate how much time a number of characters need to be repeated.

For example :

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· Jul 25, 2019 1m read
Disabling an Ensemble Production

I'm not saying that this is in anyway "best practices," but I'm in a peculiar situation where I need to restrict users from starting a "retired" Ensemble Production in a namespace that's been renamed. It's still an "Ensemble-activated" namespace; we need to keep it available for Ensemble Message Viewer access ... fortunately, only for a little while.

It's a bit of a hack ...

Open the Production class in Studio and add the following classmethod:

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Hi folks!

Want to share a lifehack with you on ObjectScript highlighiting withing VSCode for script files.

Script files are just files with lines of ObjectScript that we feed anywhere, e.g. into IRIS during Docker baking procedure.

Typical usecase - here is the Scriptfile

here is the Dockerfile where we feed it.

And here is how it looks like usually in VSCode:

Screenshot 2021-08-05 at 09 51 06

Coudl be more beautiful, right?

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· Dec 27, 2018 2m read
Use %XML.Node to walk a DOM

The following code walks a DOM using %XML.Node. It also prevents %XML.Writer to change whitespace. Run the code using the class method "test":

Class objectscript.walkDOM Extends %Persistent
    ClassMethod dfs(node As %XML.Node)
        s entrynode=node.NodeId
        do {
        //element nodes with one whitespacetyped child are the ones we want to change
        if (node.NodeType=$$$xmlELEMENTNODE){
            s snode=node.NodeId     
            if (node.MoveToFirstChild())            
                    i ('node.MoveToNextSibling()){
                        i (node.NodeType=$$$xmlWHITESPACENODE){
                            s node.NodeType=$$$xmlTEXTNODE
                            s node.NodeId=snode
            s node.NodeId=snode     
        if (node.HasChildNodes()){
            d node.MoveToFirstChild()
            d ..dfs(node)
        } while (node.NodeType'="" && node.MoveToNextSibling())
        s node.NodeId=entrynode
    ClassMethod test()
      set xml = "abcdefg"
      s reader=##class(%XML.Reader).%New()
      do reader.OpenString(xml)  
      set writer = ##class(%XML.Writer).%New()
      //do some magic
      d ..dfs(reader.Document)
      w !,"with indent=1:",!
      set writer.Indent = 1
      do writer.OutputToString()
      do writer.Document(reader.Document)
      w writer.GetXMLString()
      set writer.Indent = 0
      w !,"with indent=0:",!
      do writer.OutputToString()
      do writer.Document(reader.Document)
      w writer.GetXMLString()

Here's a link to the code on GitHub:

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I needed to pass through a file with Ensemble but the operation wasn't writing some filenames as given because the EnsLib.File.PassthroughOperation 'sanitizes' filenames removing characters that are not valid on some operating
09000655_AEDC_C3344059_A/E_Martin Browne_09000655_201706221018.pdf

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This code snippet sends an XML request to a server and saves the response to a file. The class method "test" runs the code:

Class objectscript.postXML
    classmethod test() {
        Set HTTPRequest = ##class(%Net.HttpRequest).%New()
        Set HTTPRequest.ContentType = "text/xml"
        Set HTTPRequest.NoDefaultContentCharset = 1
        Set HTTPRequest.Location = "ITOMCZ"
        Set HTTPRequest.Server = ""
        Do HTTPRequest.RemoveHeader("User-Agent")  
        Do HTTPRequest.RemoveHeader("Accept-Encoding") 
        Do HTTPRequest.RemoveHeader("Connection")
        Do HTTPRequest.SetHeader("Expect","100-continue")
        Set RequestXML = ##class(%Library.File).%New("c:\test.xml")
        Do RequestXML.Open("RS")
        Do HTTPRequest.EntityBody.CopyFrom(RequestXML)
        Do RequestXML.%Close()
        Do HTTPRequest.Post(HTTPRequest.Location)
        Do $System.OBJ.Dump(HTTPRequest)
        Do $System.OBJ.Dump(HTTPRequest.HttpResponse)
        Write HTTPRequest.HttpResponse.Data.Size
        Write HTTPRequest.ContentLength
        Set ResponseStream = ##class(%Stream.FileBinary).%New()
        // Second part is typically the file extension, i.e.: application/pdf -> pdf
        Set FileType = $Piece(HTTPRequest.HttpResponse.GetHeader("CONTENT-TYPE"),"/",2)
        Set ResponseStream.Filename = "C:\test."_FileType
        Write ResponseStream.CopyFrom(HTTPRequest.HttpResponse.Data)
        Write ResponseStream.%Save()
        Do ResponseStream.%Close()

Here's a link to the code on GitHub

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Recently I needed a classmethod that returns annotation value based on a name of a activity.

As doing it at runtime seemed inefficient, I wrote compile-time utility that iterates over all business process activities and generates relevant code.

This code could be used in a variety of situations when you need to iterate over business process activities, just add it as a secondary superclass to your BPL processes.

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We are looking at what we need to do to migrate from our current usage of Zen reports to InterSystems Reports. One of the hurdles for us is figuring out ways to interact with InterSystems reports programmatically from ObjectScript routines. There is a Java API for it, but it is possible to generate a report from InterSystems reports to a stream object in ObjectScript without diving into Java by using a %Net.HttpRequest. Here is a code example, followed by an explanation:

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This is a series of programming challenges for beginners and experienced Caché programmers.

For an introduction : go to article

You walk into a room, step on a tile and hear a loud click...

Traps !

The challenge is about avoiding traps.

You can recognise if a tile is a trap by following scheme :

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In our team, there are several developers working in parallel on different projects. To ensure this distributed collaboration and high-quality code reviews, we rely on version control with Git. Our challenge is to harmonize the unique characteristics of InterSystems products and the possibilities of Git and Docker.

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· Feb 18, 2021 2m read
Basic JSON Compare

Hi Dev Community

I thought i would share a little method I knocked together to traverse and compare 2 JSON objects for basic equivilance. I'm currently working on some data migration, and wanted a basic sanity check to validate that the JSON output is basically equivliant between the old and new, excluding a few things like timestamps.

It's a basic little recurvsive method, that will bubble up any differences over a nested structure. It's very low tech, as that's all I need it to do, but I thought it might be useful for others?

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Hello, friends who are developing IRIS. I recently participated in the InterSystems Developer Tools Contest. This time, I made a tool based on the idea described in an article I published earlier as a template for quick query of messages. Currently, you only need to establish entity classes in IRIS, Then record the message corresponding to the entity class in the specified lookup table, and all the key fields generated in the message can be inverted indexed (the concept in ElasticSearch), which is convenient for quick query. The following is the design idea of my program.

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· Sep 27, 2018 2m read
Method to Create a Class

The following class method "test" contains code that can create a new class, create new properties for classes, or create new methods for classes. "test" runs all three of these processes once, and the code that performs each action is labelled by comments in the method:

ClassMethod test() As %Status
    set sc = $$$OK
    // Create a class
    set class = ##class(%ClassDefinition).%New("MyClass")
    set class.Description = "This is my test class"_$c(13,10)_"testing %ClassDefinition"
    set class.Super = "%Persistent"

    // Create a property and add it
    set property = ##class(%PropertyDefinition).%New("MyClass.MyProperty")
    set property.Type = "%String"
    set property.Description="This is a property"
    set sc1 = class.Properties.Insert(property)
    do:$$$ISERR(sc1) $system.Status.DisplayError(sc1)
    set sc = $$$ADDSC(sc, sc1)
    // Create a method and add it
    set method = ##class(%MethodDefinition).%New("MyClass.MyMethod")
    set method.ReturnType = "%Integer"
    set method.FormalSpec = "x:%Integer,y:%Integer=10"
    set method.Description = "Return product of x and y"
    set method.CodeMode = "code"
    set method.Code = " new result"_$c(13,10)_" set result=x*y"_$c(13,10)_" quit result"
    set sc2 = class.Methods.Insert(method)
    do:$$$ISERR(sc2) $system.Status.DisplayError(sc2)
    set sc = $$$ADDSC(sc, sc2)
    // Save the class definition
    set sc3 = class.%Save()
    do:$$$ISERR(sc3) $system.Status.DisplayError(sc3)
    set sc = $$$ADDSC(sc, sc3)
    return sc

Here's a link to the code on GitHub

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· Jul 8 2m read
Character-Slice Index

A recent question from @Vivian Lee reminded me of a rather ancient example.
It was the time when DeepSee's first version was released.
We got Bitmap Index.
And we got BitSlice Index: mapping a numeric value by its binary parts.
So my idea: Why not indexing strings by their characters?
The result of this idea was presented first in June 2008.
IKnow wasn't publicly available at that time.

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Hi Developers!

Many of you are looking for samples on how to work with InterSystems IRIS Analytics, formerly known as DeepSee.

There is a Samples BI module with Patients and Holefoods examples which is available on Github with source code. The installation steps are clear but take time.

Recently we added the option to run IRIS Community Edition containers with ObjectScript Package Manager (ZPM) on board. This simplifies the installation to the "run-one-command" step for the modules submitted to ZPM Community Registry. And thus we can benefit the Samples BI installation with ZPM.

And here is how you can run it on your laptop. Let's go!

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Based on the successful solution for my 2nd contribution to the Contest
I used an adapted version for this package. And have some findings I'd like to share.

Multiple communication steps over CPIPE may take time.
You won't recognize it on a fast machine. But a slower box with
Windows + Docker Desktop + your browser (and more) is neither
"Speedy Gonzales" nor a "Road Runner". 🙂

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