Compiler

This is a translation of the following article. Thanks @Evgeny Shvarov  for the help in translation.

Let's assume that you wrote a program that shows "Hello World!", for example:

  write "Hello, World!"

The program works and everyone is happy.

With time, however, your program becomes more complex, gets more features and you eventually need to show the same string in different languages. Moreover you don't know the number and names of these languages.

The spoiler below contains a description of how the task of multi-language localization is solved in Caché.

In my previous article, we reviewed possible use-cases for macros, so let’s now proceed to a more comprehensive example of macros usability. In this article we will design and build a logging system.

Logging system

Logging system is a useful tool for monitoring the work of an application that saves a lot of time during debugging and monitoring. Our system would consist of two parts:

• Storage class (for log records)
• Set of macros that automatically add a new record to the log

The attached file contains an example of code generation using ObjectGenerators which builds a very simple homemade RuleEngine. 

Code generation is an excellent way of increasing performance moving run-time calculations to compile-time.

We could generate code creating routines or implemeting methods using ObjectGenerators. In this example we are using ObjectGenerators.

Update: Rule Engine is now on GitHub https://github.com/intersystems-ib/cache-iat-ruleengine

A very simple code generated method

For starters, let's begin with a very basic code generated method

In most cases, if one class depends on another, the class compiler will detect this and determine the correct compilation order. For example:

• Compiling a superclass triggers compilation of its subclasses.
• Compiling a custom datatype class triggers compilation of any classes with a property of that type.

Yet sometimes, a developer needs to specify compilation order. InterSystems class definitions contain two keywords for this, DependsOn and CompileAfter, that are very similar but not identical. They are useful during development, and also when importing and compiling a set of classes for the first time.

The documentation for these keywords is here

Hi all!

I'm developing a mini-framework to implement annotations in Cache. I want to support two kind of annotations: metadata and method decorators. I've got stuck trying to implement the second one.

Metadata

With metadata annotations I can add metadata to any kind of target. A target can be a method/classmethod, parameter, property and class.

For example

So another topic that has been of interest to a number of people since the beta was put up last week is in regard to Studio Hooks and Atelier. This requires a bit of background and then some discussion of how the architecture of Atelier necessitates some changes and then what our current thinking on the subject is.

Studio hooks were added to Cache over 10 years ago. They have two primary usages. The first is that on an appropriate action such as creating a new document, or compiling a document a callback is executed whose job is to interact with external source control systems. This is done by writing COS scripts that “do the right thing” for a given source control system based on the callback invoked. All of this code ran on the server and used all the facilities available on the server such as locks and transactions etc

The class %Compiler.UDL.TextServices arrived in 2015.1, bringing us methods for exporting a class in UDL format (i.e. looking just like we're used to seeing it in Studio), and importing a UDL format definition back into a namespace. Some source control tools including our Deltanji are now able to use UDL format, resulting in diffs that are easier to understand.

I have just imported our Ensemble project (not a really big one, like two man-years) into my MacBook Air  Ensemble 2016.3 instance to test many things (document model, etc.), Atelier among the others.

The "Production view" is not here, and I miss it.

The opening of Diagram Editor for BP is pretty hidden. I would even like having a switch, which would default to the Diagram Editor. 

Anytime I click on the Open Diagram Editor, it waits for a while, ten produces an error and only then I can see the diagram.

The error says: Your Studio browser is no longer valid... etc.

I cannot find an easy access to the Save or Compile command, once I do some changes in the respective BP via the Diagram Editor.

Compiling larger amount of classes produces an error: 

No conflicting files to resolve.

Compile failed: Gateway Timeout

Compiling identical set of classes "per partes" goes well, however

When I try to compile through Atelier (Compile Project), I noticed that in compilation with error it returns this message 'Failed to read /api/atelier/v1/ ...':

No additional Atelier files to synchronize.
Compile failed: Failed to read /api/atelier/v1/ERP/action/compile?flags=ck
Compile failed: Failed to read /api/atelier/v1/ERP/action/compile?flags=ck
Compile failed: Failed to read /api/atelier/v1/ERP/action/compile?flags=ck
Compile failed: Failed to read /api/atelier/v1/ERP/action/compile?flags=ck

Does anyone know what can it be?

I'm using Atelier beta (latest), with web application configured as Password Authenticated and a user with %ALL.

The definitions of these two compiler keywords looks very similar to me.

Is there any difference between these two keywords ?

When I declare a parent class as Abstract, its child class could be compiled successfully.

However, when I  declare a parent class as NoExtent, some compile errors about storage references get pop up for its child classes.

Thanks.

Is the default language (i.e., $$$DefaultLanguage, which is used as the basis for localization with $$$Text/etc. at compile time) always "en" for new Caché installations, or could it be different? How is this determined? I don't see an option to select a language during Caché installation.

Also, is there a supported/preferred API for setting the default language? Looking at %occMessages.inc, one option would be:

Set $$$DefaultLanguageNode = "en"

But I'd expect there to be a classmethod for this somewhere (and haven't managed to find it yet)

[SOLVED]

added 

>/tmp/compilew.log &>/tmp/compilew.log ; tail /tmp/compilew.log

to redirect the output to the stdout. Somehow the javac has wierd behavior with the output on errors and verbose information.

Hi,

i want the JAVA-Projections and wrappers to compile after Caché created the files. The creation of the files works 100%.

My addition to createProjection in our Projectionclass is following

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:

s cn=##Expression($$$quote(%classname))

hmmmm... compiler needs name of method's class so it "moves" the method to child class. Well, perhaps there is a good reason for that but for the moment the solution looks strange

Here's my code (download):

Class Utils.Generators [ Abstract ]
{

ClassMethod B()
{
    s ^a = 1
}

ClassMethod A() [ CodeMode = objectgenerator, GenerateAfter = B, PlaceAfter = B ]
{
    k ^a
    do ..B()
}

Now, obviously for it to work I need method B compiled and ready to use before compiling method A().

I test it with the following code:

do $system.OBJ.UnCompile("Utils.Generator")
do $system.OBJ.Compile("Utils.Generator")

Yet, I receive the following compilation error