The templates gallery

The starters live in crates/vike-script/src/templates.rs, and its header says what they are for: starter Rhai strategies for the Studio, each parameterised via param() so they drop straight into the sweep grid. templates() returns three (name, source) pairs, and every_template_compiles_and_is_parameterized compiles every one and checks that it exposes at least one param(), so a starter that will not build or cannot be swept cannot ship.

The three

• SMA cross — fast (default 5) and slow (20); long when the fast average is above the slow one, short below, reaching the target through market(...) by the delta from position(). The Studio's default editor script is the same idea with hard-coded constants; this is the sweepable form.
• RSI reversion — len (14), lo (30), hi (70); buys one unit below lo when not already long, sells one above hi when not already short.
• Donchian breakout — len (20); a symmetric proxy over sma, and the template says so in its own comment: donchian is not bound to scripts because it is multi-output (upper/mid/lower) and the bridge binds single-output indicators only, so donchian(len) would be a function-not-found at the first call rather than a silent upper-band read. Long when high() breaks above the average, short when low() breaks below.

Every template guards its warm-up with is_nan() before acting — the pattern a script over any indicator needs. Writing a strategy covers the language and the order vocabulary the verbs.

Two ways to load one

Both live in the Sweep & Validate tool. The Template dropdown plus its Load button loads blind: the selected template's full source replaces the editor buffer. Below it, the Browse templates header opens the gallery — crates/vike-studio/src/templates_gallery.rs, whose header states the difference: richer than the one-line dropdown, because you see the script before loading it. Each card shows the template's name, the first eight lines of its code in monospace with a trailing … when the script is longer (template_preview, which is pure and tested), and a Load button hugging the right edge so every card's action lines up.

Either route overwrites the editor buffer with the full template code and re-baselines the editor's unsaved-changes tracking, so a freshly loaded template is not marked dirty. gallery_ui returns true the frame Load is clicked for exactly that purpose, mirroring the indicators pane's bool-return convention.

The empty results panel offers the same thing as a getting-started action: beside ▶ Run backtest it shows "Load a template", which loads whichever template the dropdown currently selects.

Into the sweep grid

Because each starter declares its knobs with param(), "Seed from params" in the same pane fills the parameter grid from the script's declarations through vike_script::discover_params — one row per parameter, its default as the initial candidate — and ▶ Run Sweep backtests every combination of the values you type (results covers the ranked table). A discovery failure, such as a script that does not compile, clears the grid rather than raising an error; Run and Sweep report the compile error when the script is actually executed.