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#ObjectScript

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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.

We are creating a package (written in Caché Object Script) that will provide access to an external DB (MySQL). Because applications that use our package will be run from machines with various, potentially unexpected, operating systems, we’d like to establish a connection to the external DB without using DSNs (we’ve heard that setting up DSNs on certain non-Windows machines can be cumbersome and problematic).

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Article
· Jul 22, 2016 16m read
Using Regular Expressions in Caché

1.About this article

Just like Caché pattern matching, Regular Expressions can be used in Caché to identify patterns in text data – only with a much higher expressive power. This article provides a brief introduction into Regular Expressions and what you can do with it in Caché. The information provided herein is based on various sources, most notably the book “Mastering Regular Expressions” by Jeffrey Friedl and of course the Caché online documentation. The article is not intended to discuss all the possibilities and details of regular expressions. Please refer to the information sources listed in chapter 5 if you would like to learn more. If you prefer to read off-line you can also download the PDF version of this article.

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Cache tricks

Several years ago, long before Developer Community Portal was launched, I published a series of Caché tricks at one of Czech web sites. In this article, I’m posting translated version of one of them.

Capturing output of someone else’s methods or routines

Suppose you, or someone else created a useful method or routine, that was producing some computation that you’d like to benefit from, but the routine was writing output to process principal device.

You would like to use the data, but you need it not written to a device, but assigned to a variable. And, for any reason, you can’t modify the code. What can you do?

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Article
· Jul 15, 2016 5m read
Zinsert and friends: Coding in terminal

While Studio and Atelier are useful development interfaces, there are occasionally situations where a quick edit needs to be made to code and only terminal access is available. A useful set of tools to do this are the zload, zprint, zinsert, zremove, and zsave commands. These are abbreviated to zl, zp, zi, zr, and zs respectively. While each of these commands has its own page in documentation, this article will synthesize that information with examples to provide instruction for their combined use.

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I have the following problem:

  • There are several classes with method generators, which needs to be compiled during every compilation
  • I have "ckub" qualifiers enabled in studio
  • I don't want to remove "u" qualifier because I need it very much in another namespaces

So how do I force classes with method generators to recompile when "u" qualifier is present?

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Question
· Jul 13, 2016
Access namespace files

Hello, guys!

I want to get access to the folder where all files of the namespace are stored using COS. I found a way to get access to class files and found a folder where all csp, html, css etc files are stored.

However, is there any folder which contains all files(even .mac and .int)?

Or, probably, there is a method which gives all files content?

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Hi!

Here is the question in Russian Forum regarding roots extracting.

In Caché ObjectScript we use exponentiation operator (**) to raise an exponent to power. F.e. let's raise 3 to power of 3: 

USER> write 3**3 

27

And we use the same operator to extract the root. 

USER> write 27**(1/3) 

2.999999999999999963

And 2.999999999999999963 is not 3, obviously.

How to extract roots properly in Caché ObjectScript?

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Question
· Jun 14, 2016
Get variables list

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!

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Article
· Jun 13, 2016 1m read
Debug: using locks for breakpoints

Hi, Community!

Want to share with you one debugging approach from the Russian forum.

Suppose I want to debug the application and I want it to stop the execution on a particular line.

I add in code this line:

l +d,-d

When I want to start debugging in this line I block d in terminal

USER> l +d

And execute the app.

The app stops on this line and lets me connect to it with Studio debugger.

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Question
· Jun 7, 2016
Atelier bracket problem

We have noticed that when compiling with Atelier (either Atelier itself or sending the code through the REST interface) that the build will fail if all brackets '() {} []' are not closed. This includes brackets opened in comments.

For example, this will fail:

class myclass

{

//if someVar {

}

I do not know if this issue has been fixed or if this issue has been brought up, but it has been a nuisance over here.

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I would like to write some code to parse a set of HTML pages from the internet in order to gather information from each web page.

All of the web pages are generated using a template, so the format of each of the web-pages is consistent with one-another and the information that I want to gather is always located in the same logical place within the page.

What is the best way to parse an html page in order to gather information at a specific place?

Can XML XPATH be used here? Does anyone have any examples of parsing HTML content?

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Does anyone have any experience with getting, unfortunately, an older version of Cache to authenticate via SMTP to send email? I have verified that the settings are set up properly on the mailbox as I have successfully sent an email from a LAMP server, which comes from the same IP address.

If you have any thoughts, I would greatly appreciate it.

This is the error I receive

ERROR #6034: SMTP server connection failed during MAIL FROM command: <READ>zSend+105^%Net.SMTP.1.

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NewBie's Corner Session 4 The Plus Sign and Concatenation Operators

Welcome to NewBie's Corner, a weekly or biweekly post covering basic Caché Material.

Click on the Caché Cube in your system tray and select Terminal to try out the commands.

Plus Sign (+) operator

Typically, the Plus sign (+) adds two numbers together. This is true in COS (Caché ObjectScript), but COS uses it in other ways as well.

Set the variable X to a value of +12

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Question
· May 23, 2016
REST and IO redirection

Problem: I have a REST broker, and if I hit a code block, which does IO redirection, the REST reply becomes broken in one of the following ways:

  • Binary output
  • No output
  • First 4096 characters of the reply are missing

Consider the following REST broker:

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Article
· May 20, 2016 12m read
Collations in Caché

Order is a necessity for everyone, but not everyone understands it in the same way
(Fausto Cercignani)

Disclaimer: This article uses Russian language and Cyrillic alphabet as examples, but is relevant for anyone who uses Caché in a non-English locale.
Please note that this article refers mostly to NLS collations, which are different than SQL collations. SQL collations (such as SQLUPPER, SQLSTRING, EXACT which means no collation, TRUNCATE, etc.) are actual functions that are explicitly applied to some values, and whose results are sometimes explicitly stored in the global subscripts. When stored in subscripts, these values would naturally follow the NLS collation in effect (“SQL and NLS Collations”).

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Question
· May 18, 2016
Ensemble HTTP OnProcessInput

I am just trying to make a quick hand off HTTP production. I have the class built and compiled onto the server and the production is running as a service. When the production is called (by an inbound job) I can see that the HTTP.InboundAdapter is being used successfully and the stack continues all the up to ProcessInput where OnProcessInput is called in Ens.BusinessService.

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NewBie's Corner Session 2 Variables Set and Write commands

Welcome to NewBie's Corner, a weekly or biweekly post covering basic Caché Material.

Session 2 – Click on the Caché Cube in your system tray and select Terminal to try out the commands.

Variables

Like other computer programming languages, Caché uses Variables and the values they represent to control programming. Variables are elements that represent data values. Manipulating and interrogating variables is at the root of programming.

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Article
· May 13, 2016 1m read
mySQL data importer tool

Hi,

If you want to import data from a mySQL export file (exported with mysqldump), you will find here a little script that could help.

Only the INSERT commands in the sql file are executed into Caché. Indices are not computed for better performance.
%NOINDEX, %NOCHECK and %NOLOCK are generated on each INSERT line.

Currently, the file can not contain a "),(" pattern inside the values part of the INSERT command. If this is the case, the line is skipped. This feature may be implemented in the extractValuesList method.

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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.

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Hi!

I believe the simplest is (to work with csv delimited by ";"):


set file = ##class(%File).%New( "data.csv" )
    set sc = file.Open( "R" ) 
    if $$$ISERR(sc) quit    ; or do smth

    while 'file.AtEnd {
        set str=file.ReadLine() 
        for i=1:1:$length( str, ";" ) {
            set id=$piece( str, ";" ,i ) 
            write !, id  // or do smth
        }
    }
    do file.Close()

Possible options:

different variants of error handling with sc code.

Embrace while loop into try/catch block.

And what's yours?

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