Factor names like 3.14 are valid in tox for Python version-based environments, but they cannot be referenced in replace = "if" condition expressions because factor.3.14 is invalid Python syntax—the parser interprets .3.14 as a float literal. This limitation prevents users from writing conditional configuration based on Python version factors. ✨ Additionally, there was no way to check the full environment name in conditions, limiting the ability to target specific environments with conditional values.

This change adds subscript syntax for both factor and env lookups (factor['3.14'] and env['CI']) to handle names that aren't valid Python identifiers. It also introduces an env_name variable that resolves to the full environment name as a string, enabling exact name matching like env_name == 'test-3.14'. 🔧 The implementation refactors the condition evaluator by extracting helper functions to reduce complexity while maintaining full backward compatibility with existing dot-syntax expressions (factor.NAME and env.VAR).

The new syntax works seamlessly with existing configurations. Users can now write version-specific conditional dependencies in environment configurations and target specific environments by name without workarounds. Documentation has been updated across reference, how-to, explanation, and tutorial sections with practical examples.