Section Explorer

scm-js/plugin-section-explorer, installed from Plugins ▸ Browse Plugins…, is the worked example for api.document.sections and api.names: Tools ▸ Section Explorer… (Ctrl+Shift+H) is a hex editor that knows the map file. The left pane is sections.list() with badges for what the registry and the buffer say (raw, unknown, unsaved, edited, repeated, wrong size, cut short); the middle is a hex view of sections.bytes(index) drawn only for the rows on screen, coloured by the field each byte belongs to; the right is the inspector — the section's description, find and go-to, the field under the cursor with its path, value, meaning and an editing control, the raw readings in every width, and a structure tree that pages long arrays and follows the cursor.

layout.ts there is the node model: a schema (a struct of fields, an array of records, a primitive) is instantiated at an offset into a Node tree whose children are built on demand, so a terrain section of 32,768 tiles costs nothing until a row of it is looked at; pathAt / leafAt descend by arithmetic through fixed-stride arrays, leavesIn walks a byte range for the hex view's colours, and a leaf's Semantic says how its value is shown (describe, with the record's sibling values, so an action's target reads as a location, an amount or an AI script depending on the type byte) and edited (a number, a drop-down from api.names, flag ticks, text). layouts.ts is every section: the record shapes of UNIT / THG2 / DD2 / MRGN / TRIG / MBRF with one-line summaries, the fixed tables (VCOD, the settings and restriction tables per revision, PUNI, FORC, CRGB, …), the per-cell terrain and fog sections, and the string table, whose layout is read off its own offsets (one leaf per distinct blob, however many indices share it). A section longer than its layout gets a trailing-bytes leaf; a name with no layout is shown as plain bytes. buffer.ts is the edit buffer — overwrite, insert, remove, resize, with its own undo that merges a run of typing into one step — and Apply writes every changed buffer through sections.write, which is what makes the editor parse the file again. Both pure modules have tests in that repository.