Module editor 

What an editor asks the front end, and the answers, once.

docs/04-compiler-architecture.md §4.6 fixes the rule this module exists to keep: “One binary serves beck build, beck check, beck lsp and beck explain; there is no separate language server implementation to drift.” Until now that was true of the compiler and not of the editor: beck lsp held the indexing, the positions and the word-under-the-caret rule, and anything else wanting them — a playground with a <textarea> in it (docs/98 §98.9) — had to write them a second time.

So the answers live here, where beck-cli and a wasm32-unknown-unknown module can both reach them, and neither renders anything of its own:

Answer	What produces it
tokens — highlighting	beck_syntax::lexer::lex and beck_syntax::lexer::KEYWORDS
Editor::marks — inline diagnostics	the diagnostics the checker pushed
Editor::hover — a signature	crate::iface::render_item, the one beck iface writes
Editor::completions — the names in scope	the checked program’s own definition table
Editor::definition — where a name is declared	the span the checker recorded

Why the whole file, every time

An Editor is one compile. docs/64 §64.6 is why that is defensible today: the worst file in this tree costs 4.7 ms through parse, expand and check, and the median costs 0.75 ms. tokens deliberately does not need one — a file being typed into is usually a file that does not compile, and highlighting that waited for a clean parse would go out whenever it was most wanted.

Structs

Completion

One thing an editor can offer to finish the word being typed.

Editor

One document, analysed: what the front end made of the text the editor last sent.

Hint

One thing the compiler worked out and the source does not say.

Index

The names an analysis found, kept without the analysis.

Mark

One diagnostic, as an editor draws it: a byte range, a code and the text a terminal would print.

Occurrence

One place a name appears in the document.

Symbol

One name an editor can ask about.

Token

One coloured run: a byte range and what it is.

Enums

CompletionKind

HintKind

Refusal

Why a rename will not happen.

SymbolKind

TokenKind

What a run of source is, for the purpose of colouring it.

Functions

byte_of_utf16

The inverse: a UTF-16 offset back to a byte offset.

byte_offset

The inverse of utf16_position: a line and UTF-16 character back to a byte offset.

marks

Diagnostics as an editor draws them, for a caller that has the diagnostics and not an Editor — the playground’s analysis has already compiled the text and is not going to do it twice.

message_of

The message an editor shows, with the notes the terminal renderer would have printed.

tokens

Every coloured run in text, in source order, non-overlapping.

utf16_offset

A byte offset as a UTF-16 offset from the start of the text.

utf16_position

A byte offset as a zero-based line and UTF-16 character offset.

word_at

The identifier the cursor is inside or immediately after.