Removes unused `flatten_tuple` function from optimizer utilities. The
functionality was moved to the `Folder` struct, making it more
contextually appropriate. This change streamlines the utility module and
improves code organization.
Introduces the `Inliner` struct to encapsulate logic related to value
and function inlining. This improves code organization and readability
within the optimizer engine.
Key changes include:
- Moving `is_inlinable_value` to the `Inliner` struct.
- Extracting beta-reduction preparation logic into
`Inliner::prepare_beta_reduction`.
- Moving parameter slot collection to
`Inliner::collect_parameter_slots`.
- Introducing `flatten_tuple` to a new `utils` module, used by both
`Folder` and `Inliner`.
Extract common AST manipulation and folding logic into a new Folder
struct. This improves code organization and reusability. The Optimizer
now delegates these tasks to the Folder.
This commit reorganizes the optimizer code by creating a new `optimizer`
module. The `Optimizer` struct and its related logic remain in
`optimizer/optimizer.rs`, while `SubstitutionMap` and `UsageInfo` are
moved to `optimizer/substitution_map.rs`.
This change improves code organization and makes it easier to manage the
optimizer's components.