Module extract_function 

Extract-function recipe: lift a region of code into a new function.

Uses CFG liveness data from the index to determine the correct parameter list and return type for the extracted function.

Algorithm

1. Query cfg_blocks to find all blocks whose line range overlaps the selected region.
2. Run a backward-dataflow liveness pass over the whole function to compute live_in[B] / live_out[B] for every block.
3. Derive:
   • parameters = ∪(live_in[B] for B in R) ∩ vars_defined_outside_R
   • return vars = ∪(live_out[B] for B in exit_blocks(R)) ∩ vars_defined_in_R
4. Inspect cfg_effects in the region to detect async/generator/defer/acquire.
5. Inspect cfg_edges for EdgeKind::Exception edges that leave the region.
6. Generate language-appropriate source text and produce a RefactoringPlan.

Structs

ExtractFunctionOutcome

Outcome of a successful extract-function plan.

Parameter

A parameter of the extracted function.

Enums

ExtractionWarning

A warning emitted when the extraction may produce semantically surprising code.

ReturnType

Return type of the extracted function.

Functions

parse_line_range

Parse a "start-end" line-range string (e.g. "10-25") into (start, end). Lines are 1-based inclusive.

plan_extract_function

Build an extract-function plan without touching the filesystem.