Module edit 

CST mutation operations (add, remove, update fields). Edit engine for surgical CST mutations that preserve formatting.

Edits work by producing TextEdits (insertions/deletions at byte offsets) that are collected in an EditBatch and applied atomically to the source string. After applying, the caller re-parses from scratch to get a fresh CST + AST.

The key challenge is list field editing: .cabal files use several different formatting styles for list fields (single-line, leading-comma, trailing-comma, no-comma), and the edit engine must detect and follow the existing style.

Structs

EditBatch

A batch of edits to apply atomically.

TextEdit

A text edit to apply to the source.

Enums

ListStyle

The detected formatting style of a list field.

Functions

add_field_to_root

Add a new top-level metadata field to the root of the file.

add_field_to_section

Add a new field to a section at the end (before any conditionals).

add_list_item

Add an item to a list field (e.g., add a dependency to build-depends).

add_section

Add a new top-level section to the end of the file.

detect_list_style

Detect the list style of a field node.

find_field

Find a field node within a section (or the root) by field name.

find_section

Find a section node by keyword and optional name.

remove_list_item

Remove an item from a list field by prefix match on the item name.

set_field_value

Set a simple scalar field value. Replaces the current value text.