Magik Debugging Tips

System Type Debugging

What dynamics are set????

This is a good snippet of code to determine what dynamics are set when your code is executed…

How did I get here???

You can call a traceback in any method to figure out how you got there.

In 4.x, when you load the developer application, the traceback will be shown with numbers. You can get a handle on the specific call by using the global !ts![x], where x is the traceback number you are interested in. Note !ts! is overwritten on every traceback, so do a !cts! « !ts!.copy() before doing anything.

When you get a handle on the traceback line you are interested the object to which the method was called upon can be retrieved using !cts![x].receiver. And, the arguments for that method is !cts![x].arguments.

Debugging Framework & Databus

Do you need to figure out what is going on within a framework or application?

Reporting Bad Performing Consumers

Compile the following in and set your time threshold in seconds. You can use -1 to report everything going on… Once you determine your bad performer, look at sw_databus_data_available() on that consumer.

Service Providers

Do you need to know what service providers exist? A service provider is a simple way of getting to common plug-ins like maps (aka map_plugin). To get the list you can do the following.

Method Table

The exemplar.method_table gives you the details behind the inheritance of exemplars that you can use.

Find all Children

Here is an example of finding all exemplars that inherit from vtk!qa_script who has type_of_input set to :geometries

System Resources & Messages

  • smallworld_product.report_resource_loading? « _true
  • message_handler.trace_level « 3

Threads & Thread Management

There is a thread manager in the 4.x core development tools application. However sometimes it cannot be brought up, so you need to access and kill a thread on the Magik prompt…

Getting List of Threads

!t << rope.new_from_iter(system,:known_threads|()|)

Sending Error to Thread

Using a thread from above, you can run this to send an error to the thread. This is good because it will throw a traceback so you can see where things are getting stuck…


"Common" Errors

Ok, maybe not "common" but some errors and potential fixes…

  • There is no package called… probably a misplaced colon… like map_trail_plugin:activate_trail_properties_dialog() (colon should be period. PERIOD!)
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