Why This Solution is Better

Oct 13, 2025 by wbrum.org 32 views

Problem Description

When working with parameterized calculations in a filter expression, it's easy to get confused by the error message that appears when the argument is passed positionally instead of as a keyword. This can lead to frustration and wasted time trying to figure out what's going wrong.

Example Use Case

Let's take a look at an example of how this issue can arise. Suppose we have a calculation called my_calculation that takes an argument an_arg_to_the_read_action. We want to invoke this calculation from a filter expression, but we pass the argument positionally instead of as a keyword.

expr(
  my_calculation(^arg(:an_arg_to_the_read_action)) > 5
)

Current Error Message

When we try to run this expression, we get an error message that's not very helpful:

Invalid Error

     * No such function my_calculation for resource MyApp.Domain.Resource
         at filter

Proposed Solution

To improve the error message, we can check if there's a calculation with the same name as the function that was not found. If so, we can suggest the correct syntax in the error message. Here's an example of what the improved error message could look like:

  * No such function my_calculation for resource MyApp.Domain.Resource, but there is a calculation by the same name, did you mean to provide a keyword list as arguments?
         at filter

Why This Solution is Better

This solution is better because it provides more context and information to the user. By suggesting the correct syntax, we can help the user fix the issue more quickly and easily. This can save time and reduce frustration.

Alternatives Considered

We considered a few alternative solutions, but none of them seemed as effective as the proposed solution. We could have added a new error message that's more specific to the issue, but this might make the error message more confusing. We could have also added a warning message that suggests the correct syntax, but this might not be enough to help the user fix the issue.

Implementation Details

To implement this solution, we can make a change to the resource interface. We can add a new method that checks if there's a calculation with the same name as the function that was not found. If so, we can suggest the correct syntax in the error message.

No Change to Resource Necessary

However, we don't need to make any changes to the resource syntax. The solution can be implemented solely through changes to the resource interface.

Benefits of the Solution

The benefits of this solution are:

Improved error message that provides more context and information to the user
Reduced frustration and time spent trying to fix the issue
Easier to use and understand for users who are new to the system

Conclusion

Q&A

Q: What is the current error message when a calculation is invoked from an expression without keyword arguments?

A: The current error message is:

Invalid Error

     * No such function my_calculation for resource MyApp.Domain.Resource
         at filter

Q: Why is this error message not helpful?

A: This error message is not helpful because it doesn't provide any context or information about what's going wrong. It simply states that the function my_calculation was not found, without suggesting any possible solutions.

Q: What is the proposed solution to improve the error message?

A: The proposed solution is to check if there's a calculation with the same name as the function that was not found. If so, we can suggest the correct syntax in the error message. Here's an example of what the improved error message could look like:

  * No such function my_calculation for resource MyApp.Domain.Resource, but there is a calculation by the same name, did you mean to provide a keyword list as arguments?
         at filter

Q: Why is this solution better than the current error message?

A: This solution is better because it provides more context and information to the user. By suggesting the correct syntax, we can help the user fix the issue more quickly and easily.

Q: What are the benefits of this solution?

A: The benefits of this solution are:

Improved error message that provides more context and information to the user
Reduced frustration and time spent trying to fix the issue
Easier to use and understand for users who are new to the system

Q: Do we need to make any changes to the resource syntax?

A: No, we don't need to make any changes to the resource syntax. The solution can be implemented solely through changes to the resource interface.

Q: What are the implementation details of this solution?

A: To implement this solution, we can make a change to the resource interface. We can add a new method that checks if there's a calculation with the same name as the function that was not found. If so, we can suggest the correct syntax in the error message.

Q: What alternatives have you considered?

A: We considered a few alternative solutions, but none of them seemed as effective as the proposed solution. We could have added a new error message that's more specific to the issue, but this might make the error message more confusing. We could have also added a warning message that suggests the correct syntax, but this might not be enough to help the user fix the issue.

Q: What is the conclusion of this solution?

A: In conclusion, the proposed solution improves the error message when a calculation is invoked from an expression without keyword arguments. By suggesting the correct syntax, we can help users fix the issue more quickly and easily. This can save time and reduce frustration. We don't need to make any changes to the resource syntax, and the solution can be implemented solely through changes to the resource interface.