Merge pull request #4060 from dotCooCoo/feat/unknown-command-suggestion

Commands: an unknown command id is answered with the nearest command id

crates/engine/src/cmd/fileio/action_batch.rs

@@ -56,7 +56,13 @@ pub(super) fn action_batch(s: &mut Session, p: &Value) -> Result<Value> {
             return Err(bad(C, "batches cannot nest"));
         }
         if find_command(id).is_none() {
-            return Err(bad(C, format!("commands[{i}]: unknown command `{id}`")));
+            return Err(bad(
+                C,
+                match super::super::params::nearest_command(id) {
+                    Some(near) => format!("commands[{i}]: unknown command `{id}`; did you mean `{near}`?"),
+                    None => format!("commands[{i}]: unknown command `{id}`"),
+                },
+            ));
         }
     }
     let source = str_param(p, "source").unwrap_or("folder");

crates/engine/src/cmd/params.rs

@@ -20,7 +20,7 @@
 
 use serde_json::Value;
 
-use super::{bad, find_command};
+use super::{bad, command_specs, find_command};
 use crate::Result;
 
 /// What a params description says about the keys of the params object.
@@ -208,8 +208,12 @@ fn distance(a: &str, b: &str) -> usize {
 
 /// The key of `keys` a misspelt `key` most likely meant: the nearest one, when it is near.
 fn nearest<'a>(key: &str, keys: &[&'a str]) -> Option<&'a str> {
-    let near = keys.iter().map(|k| (distance(key, k), *k)).min()?;
-    (near.0 <= (key.chars().count() / 3).max(1)).then_some(near.1)
+    let len = key.chars().count();
+    let most = (len / 3).max(1);
+    // A key whose length differs by more than `most` is more than `most` edits away and isn't
+    // measured.
+    let near = keys.iter().filter(|k| k.chars().count().abs_diff(len) <= most).map(|k| (distance(key, k), *k)).min()?;
+    (near.0 <= most).then_some(near.1)
 }
 
 /// `params` has only keys the description `doc` of command `id` names, or the parameter error
@@ -480,6 +484,21 @@ pub fn check_params(id: &str, params: &Value) -> Result<()> {
     Ok(())
 }
 
+/// The command id a misspelled `id`, which names no command, most likely meant: the nearest one,
+/// when it is near (as [`check_keys`] matches a misspelled key).
+pub(crate) fn nearest_command(id: &str) -> Option<&'static str> {
+    let ids: Vec<&'static str> = command_specs().iter().map(|c| c.id).collect();
+    nearest(id, &ids)
+}
+
+/// The error for `id`, which names no command: with the nearest command id, when one is near.
+pub(crate) fn unknown_command(id: &str) -> crate::EngineError {
+    match nearest_command(id) {
+        Some(near) => crate::EngineError::UnknownCommandNear(id.to_string(), near.to_string()),
+        None => crate::EngineError::UnknownCommand(id.to_string()),
+    }
+}
+
 impl crate::Session {
     /// [`check_params`], and [`check_effect_params`] for the effects `effect.setParams` edits in
     /// this session's document (not as a step of a `command.batch`: what it edits is only there

crates/engine/src/lib.rs

@@ -44,6 +44,9 @@ pub use vectorcraft_tools as tools;
 pub enum EngineError {
     #[error("unknown command `{0}`")]
     UnknownCommand(String),
+    /// An unknown command id, with the command id it most likely misspells.
+    #[error("unknown command `{0}`; did you mean `{1}`?")]
+    UnknownCommandNear(String, String),
     #[error("command `{0}` is not available right now: {1}")]
     Disabled(String, String),
     #[error("invalid parameters for `{cmd}`: {msg}")]
@@ -1784,7 +1787,7 @@ impl Session {
 
     /// Execute a command by id. This is THE entry point for every frontend.
     pub fn execute(&mut self, id: &str, params: &Value) -> Result<Value> {
-        let spec = find_command(id).ok_or_else(|| EngineError::UnknownCommand(id.to_string()))?;
+        let spec = find_command(id).ok_or_else(|| cmd::params::unknown_command(id))?;
         // The crate's own tests are the audit of the params descriptions (#1442): a key a test
         // passes that its command's description doesn't name fails the test.
         #[cfg(test)]

crates/engine/src/tests.rs

@@ -90,6 +90,42 @@ fn unknown_and_disabled() {
     assert!(matches!(s.execute("object.group", &json!({})), Err(EngineError::Disabled(..))));
 }
 
+#[test]
+fn unknown_command_names_the_nearest_id() {
+    let mut s = session();
+    for typo in ["select.al", "Select.All", "selcet.all"] {
+        let e = s.execute(typo, &json!({})).unwrap_err();
+        assert!(matches!(&e, EngineError::UnknownCommandNear(id, near) if id == typo && near == "select.all"), "{typo}: {e:?}");
+        assert_eq!(e.to_string(), format!("unknown command `{typo}`; did you mean `select.all`?"));
+    }
+    let e = s.execute("nope", &json!({})).unwrap_err();
+    assert!(matches!(&e, EngineError::UnknownCommand(id) if id == "nope"), "{e:?}");
+    assert_eq!(e.to_string(), "unknown command `nope`");
+    let e = s.execute("command.batch", &json!({"commands": [{"command": "select.al", "params": {}}]})).unwrap_err();
+    assert!(e.to_string().contains("did you mean `select.all`?"), "{e}");
+}
+
+#[test]
+fn a_long_unknown_command_id_is_answered_at_once() {
+    let mut s = session();
+    let long = "x".repeat(200_000);
+    let start = std::time::Instant::now();
+    assert!(matches!(s.execute(&long, &json!({})), Err(EngineError::UnknownCommand(_))));
+    let e = crate::check_params("file.new", &json!({ long.as_str(): 1 })).unwrap_err();
+    assert!(e.to_string().contains("the command takes:"), "{e}");
+    assert!(start.elapsed() < std::time::Duration::from_secs(2), "{:?}", start.elapsed());
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+#[test]
+fn action_batch_names_the_nearest_command_id() {
+    let mut s = session();
+    let e = s.execute("action.batch", &json!({"source": "dataSets", "commands": [{"command": "select.al"}]})).unwrap_err();
+    assert_eq!(e.to_string(), "invalid parameters for `action.batch`: commands[0]: unknown command `select.al`; did you mean `select.all`?");
+    let e = s.execute("action.batch", &json!({"source": "dataSets", "commands": [{"command": "nope"}]})).unwrap_err();
+    assert_eq!(e.to_string(), "invalid parameters for `action.batch`: commands[0]: unknown command `nope`");
+}
+
 #[test]
 fn group_ungroup() {
     let mut s = session();

crates/ui-egui/src/i18n/bg.tsv

@@ -4224,6 +4224,7 @@ axis	Both	И двете
 @msg	tool shortcuts must be a single key (optionally with Shift)	клавишните комбинации за инструменти трябва да са един клавиш (по избор със Shift)
 @msg	truncated	съкратено
 @msg	unknown command `{0}`	непозната команда `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	непозната команда `{0}`; имахте ли предвид `{1}`?
 @msg	unknown effect `{id}`	непознат ефект `{id}`
 @msg	unknown format	непознат формат
 @msg	unknown format `{f}` (Save writes {_1})	непознат формат `{f}` (Запазването записва {_1})

crates/ui-egui/src/i18n/cs.tsv

@@ -4629,6 +4629,7 @@ imageTrace	Outline	Obrys
 @msg	tool shortcuts must be a single key (optionally with Shift)	zkratky nástrojů musí být jediná klávesa (volitelně se Shift)
 @msg	truncated	zkráceno
 @msg	unknown command `{0}`	neznámý příkaz `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	neznámý příkaz `{0}`; mysleli jste `{1}`?
 @msg	unknown effect `{id}`	neznámý efekt `{id}`
 @msg	unknown format	neznámý formát
 @msg	unknown format `{f}` (Save writes {_1})	neznámý formát `{f}` (Uložit zapisuje {_1})

crates/ui-egui/src/i18n/da.tsv

@@ -4324,6 +4324,7 @@ imageTrace	Outline	Kontur
 @msg	tool shortcuts must be a single key (optionally with Shift)	værktøjsgenveje skal være en enkelt tast (eventuelt med Skift)
 @msg	truncated	afkortet
 @msg	unknown command `{0}`	ukendt kommando `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	ukendt kommando `{0}`; mente du `{1}`?
 @msg	unknown effect `{id}`	ukendt effekt `{id}`
 @msg	unknown format	ukendt format
 @msg	unknown format `{f}` (Save writes {_1})	ukendt format `{f}` (Gem skriver {_1})

crates/ui-egui/src/i18n/de.tsv

@@ -4252,6 +4252,7 @@ theme	Appearance	Erscheinungsbild
 @msg	tool shortcuts must be a single key (optionally with Shift)	Tastaturbefehle für Werkzeuge müssen aus einer einzelnen Taste bestehen (optional mit Shift)
 @msg	truncated	abgeschnitten
 @msg	unknown command `{0}`	unbekannter Befehl `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	unbekannter Befehl `{0}`; meinten Sie `{1}`?
 @msg	unknown effect `{id}`	unbekannter Effekt `{id}`
 @msg	unknown format	unbekanntes Format
 @msg	unknown format `{f}` (Save writes {_1})	unbekanntes Format `{f}` („Speichern“ schreibt {_1})

crates/ui-egui/src/i18n/el.tsv

@@ -4300,6 +4300,7 @@ theme	Appearance	Εμφάνιση
 @msg	tool shortcuts must be a single key (optionally with Shift)	οι συντομεύσεις εργαλείων πρέπει να περιλαμβάνουν ένα πλήκτρο (προαιρετικά με Shift)
 @msg	truncated	περικομμένο
 @msg	unknown command `{0}`	άγνωστη εντολή `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	άγνωστη εντολή `{0}`· μήπως εννοείτε `{1}`;
 @msg	unknown effect `{id}`	άγνωστο εφέ `{id}`
 @msg	unknown format	άγνωστη μορφή
 @msg	unknown format `{f}` (Save writes {_1})	άγνωστη μορφή `{f}` (η Αποθήκευση υποστηρίζει {_1})

crates/ui-egui/src/i18n/es.tsv

@@ -4327,6 +4327,7 @@ axis	Both	Ambos
 @msg	tool shortcuts must be a single key (optionally with Shift)	los atajos de herramientas deben ser una sola tecla (opcionalmente con Shift)
 @msg	truncated	truncado
 @msg	unknown command `{0}`	comando desconocido `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	comando desconocido `{0}`; ¿quiso decir `{1}`?
 @msg	unknown effect `{id}`	efecto desconocido `{id}`
 @msg	unknown format	formato desconocido
 @msg	unknown format `{f}` (Save writes {_1})	formato desconocido `{f}` (Guardar escribe {_1})

crates/ui-egui/src/i18n/fi.tsv

@@ -4536,6 +4536,7 @@ imageTrace	Outline	Ääriviiva
 @msg	tool shortcuts must be a single key (optionally with Shift)	työkalujen pikanäppäinten on oltava yksittäinen näppäin (valinnaisesti Vaihto-näppäimen kanssa)
 @msg	truncated	katkaistu
 @msg	unknown command `{0}`	tuntematon komento `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	tuntematon komento `{0}`; tarkoititko `{1}`?
 @msg	unknown effect `{id}`	tuntematon tehoste `{id}`
 @msg	unknown format	tuntematon muoto
 @msg	unknown format `{f}` (Save writes {_1})	tuntematon muoto `{f}` (Tallenna kirjoittaa muotoja {_1})

crates/ui-egui/src/i18n/fr.tsv

@@ -4324,6 +4324,7 @@ axis	Both	Les deux
 @msg	tool shortcuts must be a single key (optionally with Shift)	les raccourcis d’outils doivent être une seule touche (éventuellement avec Maj)
 @msg	truncated	tronqué
 @msg	unknown command `{0}`	commande inconnue `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	commande inconnue `{0}` ; vouliez-vous dire `{1}` ?
 @msg	unknown effect `{id}`	effet inconnu `{id}`
 @msg	unknown format	format inconnu
 @msg	unknown format `{f}` (Save writes {_1})	format inconnu `{f}` (Enregistrer écrit {_1})

crates/ui-egui/src/i18n/hu.tsv

@@ -5075,6 +5075,7 @@ imageTrace	Outline	Körvonal
 @msg	truncated	csonka
 @msg	Unembedded to {_1}	Beágyazás megszüntetve, ide: {_1}
 @msg	unknown command `{0}`	ismeretlen parancs: `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	ismeretlen parancs: `{0}`; erre gondolt: `{1}`?
 @msg	unknown effect `{id}`	ismeretlen effektus: `{id}`
 @msg	unknown format	ismeretlen formátum
 @msg	unknown format `{f}` (Save writes {_1})	ismeretlen formátum: `{f}` (a Mentés ezeket írja: {_1})

crates/ui-egui/src/i18n/id.tsv

@@ -4324,6 +4324,7 @@ imageTrace	Outline	Kontur
 @msg	tool shortcuts must be a single key (optionally with Shift)	pintasan alat harus satu tombol (opsional dengan Shift)
 @msg	truncated	terpotong
 @msg	unknown command `{0}`	perintah `{0}` tidak dikenal
+@msg	unknown command `{0}`; did you mean `{1}`?	perintah `{0}` tidak dikenal; apakah maksud Anda `{1}`?
 @msg	unknown effect `{id}`	efek `{id}` tidak dikenal
 @msg	unknown format	format tidak dikenal
 @msg	unknown format `{f}` (Save writes {_1})	format `{f}` tidak dikenal (Simpan menulis {_1})

crates/ui-egui/src/i18n/it.tsv

@@ -4367,6 +4367,7 @@ axis	Both	Entrambi
 @msg	tool shortcuts must be a single key (optionally with Shift)	le scelte rapide degli strumenti devono essere un singolo tasto (eventualmente con Shift)
 @msg	truncated	troncato
 @msg	unknown command `{0}`	comando sconosciuto `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	comando sconosciuto `{0}`; forse intendevate `{1}`?
 @msg	unknown effect `{id}`	effetto sconosciuto `{id}`
 @msg	unknown format	formato sconosciuto
 @msg	unknown format `{f}` (Save writes {_1})	formato sconosciuto `{f}` (Salva scrive {_1})

crates/ui-egui/src/i18n/ja.tsv

@@ -4190,6 +4190,7 @@ swatch	Bright Violet	ビビッドバイオレット
 @msg	objects can't be nested more than 32 deep	オブジェクトは 32 階層より深く入れ子にできません
 @msg	the SVG's elements are nested more than {0} deep	SVG の要素が {0} 階層より深く入れ子になっています
 @msg	unknown command `{0}`	`{0}` は不明なコマンドです
+@msg	unknown command `{0}`; did you mean `{1}`?	`{0}` は不明なコマンドです。`{1}` のことですか?
 @msg	`{what}` closes nothing	`{what}` に対応する開始部分がありません
 @msg	`{what}` closes something it didn't open	`{what}` が対応しない開始部分を閉じています
 @msg	a path has too many points	ポイントが多すぎるパスがあります

crates/ui-egui/src/i18n/ka.tsv

@@ -4089,6 +4089,7 @@ font-technology	Variable	ცვლადი
 @msg	tool shortcuts must be a single key (optionally with Shift)	ხელსაწყოს მალსახმობი ერთი კლავიში უნდა იყოს (სურვილისამებრ Shift-ით)
 @msg	truncated	შეკვეცილია
 @msg	unknown command `{0}`	უცნობი ბრძანება `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	უცნობი ბრძანება `{0}`; იქნებ `{1}` იგულისხმეთ?
 @msg	unknown effect `{id}`	უცნობი ეფექტი `{id}`
 @msg	unknown format	უცნობი ფორმატი
 @msg	unknown format `{f}` (Save writes {_1})	უცნობი ფორმატი `{f}` (შენახვა წერს: {_1})

crates/ui-egui/src/i18n/ko.tsv

@@ -4122,6 +4122,7 @@ theme	Appearance	외관
 @msg	objects can't be nested more than 32 deep	개체는 32단계보다 깊게 중첩할 수 없습니다
 @msg	the SVG's elements are nested more than {0} deep	SVG 요소가 {0}단계보다 깊게 중첩되어 있습니다
 @msg	unknown command `{0}`	알 수 없는 명령 `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	알 수 없는 명령 `{0}`: `{1}`을(를) 의미하셨습니까?
 @msg	`{what}` closes nothing	`{what}`이(가) 닫는 항목이 없습니다
 @msg	`{what}` closes something it didn't open	`{what}`이(가) 열지 않은 항목을 닫습니다
 @msg	a path has too many points	패스의 점이 너무 많습니다

crates/ui-egui/src/i18n/nl.tsv

@@ -4336,6 +4336,7 @@ imageTrace	Outline	Contour
 @msg	tool shortcuts must be a single key (optionally with Shift)	gereedschapsneltoetsen moeten uit één toets bestaan (eventueel met Shift)
 @msg	truncated	afgekapt
 @msg	unknown command `{0}`	onbekende opdracht `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	onbekende opdracht `{0}`; bedoelde je `{1}`?
 @msg	unknown effect `{id}`	onbekend effect `{id}`
 @msg	unknown format	onbekende indeling
 @msg	unknown format `{f}` (Save writes {_1})	onbekende indeling `{f}` (Opslaan schrijft {_1})

crates/ui-egui/src/i18n/pl.tsv

@@ -4454,6 +4454,7 @@ imageTrace	Outline	Kontur
 @msg	tool shortcuts must be a single key (optionally with Shift)	skróty narzędzi muszą być pojedynczym klawiszem (opcjonalnie z Shift)
 @msg	truncated	obcięty
 @msg	unknown command `{0}`	nieznane polecenie `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	nieznane polecenie `{0}`; czy chodziło o `{1}`?
 @msg	unknown effect `{id}`	nieznany efekt `{id}`
 @msg	unknown format	nieznany format
 @msg	unknown format `{f}` (Save writes {_1})	nieznany format `{f}` (zapis tworzy {_1})

crates/ui-egui/src/i18n/pt-br.tsv

@@ -3900,6 +3900,7 @@ axis	Both	Ambos
 @msg	tool shortcuts must be a single key (optionally with Shift)	os atalhos de ferramenta devem ser uma única tecla (opcionalmente com Shift)
 @msg	truncated	truncado
 @msg	unknown command `{0}`	comando desconhecido `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	comando desconhecido `{0}`; você quis dizer `{1}`?
 @msg	unknown effect `{id}`	efeito desconhecido `{id}`
 @msg	unknown format	formato desconhecido
 @msg	unknown format `{f}` (Save writes {_1})	formato desconhecido `{f}` (Salvar grava {_1})

crates/ui-egui/src/i18n/ru.tsv

@@ -4363,6 +4363,7 @@ axis	Both	Оба
 @msg	tool shortcuts must be a single key (optionally with Shift)	сочетания инструментов должны быть одной клавишей (необязательно с Shift)
 @msg	truncated	усечено
 @msg	unknown command `{0}`	неизвестная команда `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	неизвестная команда `{0}`; возможно, имелась в виду `{1}`?
 @msg	unknown effect `{id}`	неизвестный эффект `{id}`
 @msg	unknown format	неизвестный формат
 @msg	unknown format `{f}` (Save writes {_1})	неизвестный формат `{f}` (сохранение записывает {_1})

crates/ui-egui/src/i18n/sv.tsv

@@ -4236,6 +4236,7 @@ axis	Both	Båda
 @msg	tool shortcuts must be a single key (optionally with Shift)	kortkommandon för verktyg måste vara en enda tangent (eventuellt med Shift)
 @msg	truncated	avkortad
 @msg	unknown command `{0}`	okänt kommando `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	okänt kommando `{0}`; menade du `{1}`?
 @msg	unknown effect `{id}`	okänd effekt `{id}`
 @msg	unknown format	okänt format
 @msg	unknown format `{f}` (Save writes {_1})	okänt format `{f}` (Spara skriver {_1})

crates/ui-egui/src/i18n/tr.tsv

@@ -4090,6 +4090,7 @@ axis	Both	Her İkisi
 @msg	tool shortcuts must be a single key (optionally with Shift)	araç kısayolları tek tuş olmalıdır (isteğe bağlı olarak Shift ile)
 @msg	truncated	kesik
 @msg	unknown command `{0}`	bilinmeyen komut `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	bilinmeyen komut `{0}`; `{1}` mi demek istediniz?
 @msg	unknown effect `{id}`	bilinmeyen etki `{id}`
 @msg	unknown format	bilinmeyen format
 @msg	unknown format `{f}` (Save writes {_1})	bilinmeyen format `{f}` (Kaydet, {_1} yazar)

crates/ui-egui/src/i18n/uk.tsv

@@ -4351,6 +4351,7 @@ axis	Both	Обидві
 @msg	tool shortcuts must be a single key (optionally with Shift)	поєднання інструментів має бути однією клавішею (необов’язково з Shift)
 @msg	truncated	усічено
 @msg	unknown command `{0}`	невідома команда `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	невідома команда `{0}`; можливо, ви мали на увазі `{1}`?
 @msg	unknown effect `{id}`	невідомий ефект `{id}`
 @msg	unknown format	невідомий формат
 @msg	unknown format `{f}` (Save writes {_1})	невідомий формат `{f}` (збереження записує {_1})

crates/ui-egui/src/i18n/vi.tsv

@@ -4730,6 +4730,7 @@ theme	Appearance	Giao diện
 @msg	truncated	bị cắt ngắn
 @msg	Unembedded to {_1}	Đã bỏ nhúng vào {_1}
 @msg	unknown command `{0}`	lệnh không xác định `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	lệnh không xác định `{0}`; ý bạn là `{1}`?
 @msg	unknown effect `{id}`	hiệu ứng không xác định `{id}`
 @msg	unknown format	định dạng không xác định
 @msg	unknown format `{f}` (Save writes {_1})	định dạng không xác định `{f}` (Lưu ghi {_1})

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -3921,6 +3921,7 @@ imageTrace	Outline	轮廓
 @msg	objects can't be nested more than 32 deep	对象的嵌套不能超过 32 层
 @msg	the SVG's elements are nested more than {0} deep	SVG 的元素嵌套超过 {0} 层
 @msg	unknown command `{0}`	未知命令 `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	未知命令 `{0}`；您是否想输入 `{1}`？
 @msg	`{what}` closes nothing	`{what}` 没有可结束的内容
 @msg	`{what}` closes something it didn't open	`{what}` 结束了并非由它开始的内容
 @msg	a path has too many points	某条路径的点过多

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -1901,6 +1901,7 @@ file-filter	Templates	範本
 @msg	objects can't be nested more than 32 deep	物件的巢狀層級不能超過 32 層
 @msg	the SVG's elements are nested more than {0} deep	SVG 的元素巢狀超過 {0} 層
 @msg	unknown command `{0}`	未知的指令 `{0}`
+@msg	unknown command `{0}`; did you mean `{1}`?	未知的指令 `{0}`；您是指 `{1}` 嗎？
 @msg	`{what}` closes nothing	`{what}` 沒有可結束的內容
 @msg	`{what}` closes something it didn't open	`{what}` 結束了並非由它開始的內容
 @msg	a path has too many points	有一條路徑的點過多

docs/mcp.md

@@ -1030,6 +1030,14 @@ of the format they write (one object can carry several formats' options). A comm
 (`document.setup`, `text.areaOptions`) says so the same way. The app's own journal isn't checked: an action or
 journal recorded by an older version replays as it did, except for an effect `color` that the effect can't read.
 
+An unknown command id is matched the same way as an unknown parameter key: the error names the nearest command id when
+one is near, ignoring case. A step of `command.batch` or `action.batch` gets the same suggestion in its step error:
+
+```json
+{"id": "select.al"}
+→ unknown command `select.al`; did you mean `select.all`?
+```
+
 These Object menu commands refuse a string or another value that is not a number with
 `` `scaleH` must be a number, not "50" ``, naming the key, and change nothing: `scaleH`, `scaleV`, `moveH`, `moveV`
 and `rotate` in `object.transformEach`; `ppi` in `object.rasterize`; `width`, `height`, `spacingX` and `spacingY` in