Module code_view 

Read-only code, with line numbers and marked lines.

No grammar, and no new dependency

Deciding that a word is a keyword needs a grammar, which is the same kind of fact the calendar is: answered correctly only by the library the application already depends on. docs/coverage.md records syntax highlighting as out of scope, and this view keeps that line — it takes pre-classified spans from the caller, exactly as Markdown colours a fenced block.

What the caller owes, per line:

1. the line’s own text, with no newline in it;
2. CodeSpan ranges in byte offsets into that line’s text, not into the whole document, on character boundaries;
3. ranges sorted ascending and not overlapping.

A span that breaks any of those is skipped rather than drawn wrongly: the line stays readable without its colour, and colour that landed in the wrong place would be a lie about the code. This is the same boundary crate::display::highlight states for search hits, and it is deliberately the same one.

Long lines scroll, they do not wrap

In prose a wrap is invisible; in code a column carries meaning. Indentation is structure, an aligned comment is a column, and a diagnostic that says “column 34” is pointing at a place a wrapped line no longer has. Wrapping also breaks the one thing the gutter claims — that line 41 is one row — so a marked line would stop lining up with its mark. So a long line runs off the edge and the view scrolls to it.

Size, and what virtualization costs here

With no CodeView::visible_lines every line is laid out inside a ScrollArea that scrolls both ways, which is the mode that keeps the horizontal scroll above.

With visible_lines the body becomes the virtualized List, which draws only the rows the viewport holds — and then the horizontal scroll goes, for the reason DataGrid already states: uniform_list owns its own scroll offset and lays every row out at the width it is given. A long line is clipped at the frame in that mode. The two are named rather than blended, because a view that silently dropped the right-hand half of a line would be worse than one that says which mode it is in.

Copying

GPUI offers no text-selection primitive, which docs/coverage.md records as a library-wide gap; nothing rendered here can be selected with a pointer. So the view carries a control that copies the whole text, the way a Markdown code block does, and does not pretend a caret exists.

Structs

CodeLine

One line of code, identified by its number.

CodeView

Read-only code with a gutter.

Enums

LineMark

What a line is being called out for.