Generalise numeric action application

[DillonZChen]

Extend eval_function_term for conditions like

(<= (+ (truck_y) 1) (max_y))

and apply_effects_to_state for effects like

(assign (at_x ?p) (+ (max_x) 1))

[morxa]

Can you rebase this onto main so the CI pipeline (new in main) is triggered?

[Copilot]

Pull Request Overview

This PR aims to generalise the numeric action application in the state space generator by extending the evaluation functions for numeric expressions (e.g. the Plus operation) and updating how effects are applied to state representations.

• Extended eval_function_term to support addition (Plus)
• Modified state_to_string to build a comma-separated, sorted string of predicates
• Improved handling of numeric effects in apply_effects_to_state by removing direct reliance on the NumericValue attribute

Comments suppressed due to low confidence (3)

genfond/state_space_generator.py:52

• [nitpick] Sorting state string components may change the intended order of predicates. Verify if sorting is deliberate or if the original insertion order should be maintained.

return ",".join(sorted(state_str))

genfond/state_space_generator.py:137

• Clarify the intent of the else branch in the BinaryFunction evaluation. Consider handling this case explicitly or documenting why it is expected to occur.

# DZC: What is this else case?

genfond/state_space_generator.py:141

• Ensure that removing the assertion for NumericValue is safe by confirming that eval_function_term correctly computes a numeric value. Update tests to cover scenarios where numeric effects are processed without explicit NumericValue usage.

# DZC: remove this assert by evaluating change = eval_function_term(...)