Question Block

Question Block

Where Is It?

The question block is found in the Primary drawer of the Blawx toolbox.

What Does It Do?

The question block is used to send a question to the Blawx reasoner, and get one or more answers based on the code provided.

In most programming languages, all of the code that you write tells the computer what to "do". In Blawx, that's not true. Most of the code tells the computer what it "knows," and only question blocks ask the computer to do anything.

So if you have code, but no question block, when you click "Run", nothing much will happen!

Technical Details

The question block accepts a single stack of statements, which is valid if it is a stack of at least one statement. The stack is treated as if all of its parts were joined together with "and". All of the statements must be true at the same time for an answer to be included. Variables in the stack share a single scope, so anywhere you are using the same variable name you are referring to the same object.

(Remember that the opposite is not true. If you use different variable names, that does not necessarily mean you are referring to different objects. To ensure that you include results only where two variables do not refer to the same object, use the object disequality block.)

The question block will return a number of models, where each model represents a combination of an answer to the question, and a way of obtaining that answer. If there are two possible answers, and three ways of obtaining each answer, you will get six models.

While it is possible to have more than one question block in a workspace, only the last active question block will actually be used by the software.


If your question block returns the answer "no models found", but you think that it should be finding answers, here are a few good troubleshooting tricks:

  1. Try removing statements from the question block until you get an answer, and then adding them back in until you find which statement is failing.
  2. Try removing variables from the question block and replacing them with object selectors that you think should have been returned.
  3. Try using assumption blocks to see if adding or removing assumptions from your code changes the result.
  4. If your query is a single statement, try surrounding it with a not block, to see if Blawx can explain why no answer was found.