formulas.recentlyUsed scanned the session journal for cell.set inputs.
It missed formulas entered by range.* commands, lost them when the
journal dropped its oldest entries (a large file open or a long script
is enough), and started empty in every session. The Function Library's
Recently Used menu and the Insert Function dialog list what it returns.
- Prefs::recent_functions (a new engine module, recent.rs) holds the
ten functions most recently entered in a formula, newest first.
Session::execute updates it for every cell.* and range.* command it
journals, from any source (the interface, the control channel, MCP or
a script). It reads at most 2,000 of the formulas a command enters,
starting from the last one; formulas longer than Excel's limit are
skipped. formulas.recentlyUsed
returns it. It never reads the journal back, so the journal's caps do
not affect it.
- The list is kept with the other engine preferences (prefs.json, the
browser's storage on the web), so it survives a restart as Excel's
does. It is read leniently: a malformed value loses only this list. A
fresh install starts from common functions.
The Insert Function dialog is titled "Insert Function", as in Excel (it
said "Formula Builder"), and gains a working category list: Most
Recently Used, All, then each category in Excel's order. A category may
be given by label or by engine id, so a Function Library menu or the
control channel (ui.dialog.set) opens it on one, and a new search
switches to All. The dialog keeps its translated labels and its search
in the interface language. Each row shows the function's name and its
category in two columns; the category column starts after the widest
name shown, so a long name in any font or formula language stays clear
of it. A function counts as recently used once its formula is entered,
not when OK is pressed. The unused "Formula Builder" translations are
removed.
Tests: engine unit tests for reading functions from formulas (strings,
unknown names, over-long and malformed formulas), the formulas a
command enters (newest first, within the budget), the ten-name list
and the lenient read of prefs.json; tests/it/recently_used.rs for
cell.set and range.setValues from the session, a failed command, a
cleared journal and a save and reload of the preferences. UI tests for
the menu's order and the dialog's title, categories, engine-id
category, search and OK, and for the category column with a wide font.
