Scenario conditions in dialogs: option if= hides choices, when moved here from stat checks; command schemas

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

locale/schema_en.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = Line
+dialog/schema/builtin/text_desc = A dialog line; the locale key is optional
+dialog/schema/field/text = Text
+dialog/schema/field/locale_key = Locale key
+dialog/schema/builtin/ptext = Narration
+dialog/schema/builtin/ptext_desc = The narrator text, fills ${var}
+dialog/schema/builtin/flag = Story flag
+dialog/schema/builtin/flag_desc = A saved mark that conditions react to
+dialog/schema/field/flag = Flag
+dialog/schema/field/value = Value
+dialog/schema/builtin/switch_scene = Switch scene
+dialog/schema/builtin/switch_scene_desc = A novel scene or a map — a map is a scene too
+dialog/schema/field/scene = Scene
+dialog/schema/builtin/goto = Go to a label
+dialog/schema/builtin/goto_desc = An unconditional jump
+dialog/schema/field/label = Label
+dialog/schema/builtin/end = End the dialog
+dialog/schema/builtin/end_desc = Closes the dialog box
+dialog/schema/checks/when = When — jump
+dialog/schema/checks/when_desc = A conditional jump on the shared condition language: flags, quests, stats, gear
+dialog/schema/checks/arrow_true = When true, go to
+dialog/schema/field/condition = Condition
+dialog/schema/field/else = Else label
+dialog/schema/builtin/select = Choice
+dialog/schema/builtin/select_desc = The question before the answers; option lines follow
+dialog/schema/builtin/option = Answer
+dialog/schema/builtin/option_desc = An answer and the label it leads to; with a condition it is shown only while it holds
+dialog/schema/field/option_if = Show if
+dialog/schema/builtin/option_if_desc = For example archetype(rogue) or "stat(cha) >= 5"; empty — always

locale/schema_es.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = Réplica
+dialog/schema/builtin/text_desc = Una línea de diálogo; la clave de traducción es opcional
+dialog/schema/field/text = Texto
+dialog/schema/field/locale_key = Clave de traducción
+dialog/schema/builtin/ptext = Narración
+dialog/schema/builtin/ptext_desc = El texto del narrador, rellena ${var}
+dialog/schema/builtin/flag = Marca de historia
+dialog/schema/builtin/flag_desc = Una marca guardada a la que reaccionan las condiciones
+dialog/schema/field/flag = Marca
+dialog/schema/field/value = Valor
+dialog/schema/builtin/switch_scene = Cambiar de escena
+dialog/schema/builtin/switch_scene_desc = Una escena de novela o un mapa: un mapa también es una escena
+dialog/schema/field/scene = Escena
+dialog/schema/builtin/goto = Ir a una etiqueta
+dialog/schema/builtin/goto_desc = Un salto incondicional
+dialog/schema/field/label = Etiqueta
+dialog/schema/builtin/end = Fin del diálogo
+dialog/schema/builtin/end_desc = Cierra el cuadro de diálogo
+dialog/schema/checks/when = Si — saltar
+dialog/schema/checks/when_desc = Un salto condicional según el lenguaje común de condiciones: marcas, misiones, estadísticas, equipo
+dialog/schema/checks/arrow_true = Si es cierto, ir a
+dialog/schema/field/condition = Condición
+dialog/schema/field/else = Etiqueta si no
+dialog/schema/builtin/select = Elección
+dialog/schema/builtin/select_desc = La pregunta antes de las respuestas; siguen las líneas option
+dialog/schema/builtin/option = Respuesta
+dialog/schema/builtin/option_desc = Una respuesta y la etiqueta a la que lleva; con condición solo se muestra mientras se cumple
+dialog/schema/field/option_if = Mostrar si
+dialog/schema/builtin/option_if_desc = Por ejemplo archetype(rogue) o "stat(cha) >= 5"; vacío: siempre

locale/schema_ja.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = セリフ
+dialog/schema/builtin/text_desc = 会話の一行。翻訳キーは任意
+dialog/schema/field/text = テキスト
+dialog/schema/field/locale_key = 翻訳キー
+dialog/schema/builtin/ptext = 地の文
+dialog/schema/builtin/ptext_desc = 語りの文。${var} を埋め込む
+dialog/schema/builtin/flag = ストーリーフラグ
+dialog/schema/builtin/flag_desc = 保存される印。条件がそれに反応する
+dialog/schema/field/flag = フラグ
+dialog/schema/field/value = 値
+dialog/schema/builtin/switch_scene = シーン切り替え
+dialog/schema/builtin/switch_scene_desc = ノベルのシーンかマップ——マップもシーン
+dialog/schema/field/scene = シーン
+dialog/schema/builtin/goto = ラベルへ移動
+dialog/schema/builtin/goto_desc = 無条件のジャンプ
+dialog/schema/field/label = ラベル
+dialog/schema/builtin/end = 会話の終わり
+dialog/schema/builtin/end_desc = 会話ウィンドウを閉じる
+dialog/schema/checks/when = もし——ジャンプ
+dialog/schema/checks/when_desc = 共通の条件言語による条件ジャンプ：フラグ、クエスト、ステータス、装備
+dialog/schema/checks/arrow_true = 真のときのラベル
+dialog/schema/field/condition = 条件
+dialog/schema/field/else = それ以外のラベル
+dialog/schema/builtin/select = 選択肢
+dialog/schema/builtin/select_desc = 選択肢の前の問い。続けて option 行
+dialog/schema/builtin/option = 選択肢
+dialog/schema/builtin/option_desc = 答えと行き先のラベル。条件付きなら成り立つ間だけ表示
+dialog/schema/field/option_if = 表示条件
+dialog/schema/builtin/option_if_desc = 例：archetype(rogue) や "stat(cha) >= 5"。空なら常に

locale/schema_ko.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = 대사
+dialog/schema/builtin/text_desc = 대화 한 줄. 번역 키는 선택
+dialog/schema/field/text = 텍스트
+dialog/schema/field/locale_key = 번역 키
+dialog/schema/builtin/ptext = 서술
+dialog/schema/builtin/ptext_desc = 서술자 텍스트. ${var}를 채움
+dialog/schema/builtin/flag = 스토리 플래그
+dialog/schema/builtin/flag_desc = 저장되는 표시. 조건이 반응합니다
+dialog/schema/field/flag = 플래그
+dialog/schema/field/value = 값
+dialog/schema/builtin/switch_scene = 장면 전환
+dialog/schema/builtin/switch_scene_desc = 노벨 장면이나 맵 — 맵도 장면입니다
+dialog/schema/field/scene = 장면
+dialog/schema/builtin/goto = 라벨로 이동
+dialog/schema/builtin/goto_desc = 무조건 이동
+dialog/schema/field/label = 라벨
+dialog/schema/builtin/end = 대화 끝
+dialog/schema/builtin/end_desc = 대화창을 닫음
+dialog/schema/checks/when = 조건 — 이동
+dialog/schema/checks/when_desc = 공통 조건 언어로 하는 조건 이동: 플래그, 퀘스트, 능력치, 장비
+dialog/schema/checks/arrow_true = 참이면 이동
+dialog/schema/field/condition = 조건
+dialog/schema/field/else = 아니면 라벨
+dialog/schema/builtin/select = 선택
+dialog/schema/builtin/select_desc = 답 앞의 질문. 뒤에 option 줄이 옵니다
+dialog/schema/builtin/option = 선택지
+dialog/schema/builtin/option_desc = 답과 이어지는 라벨. 조건이 있으면 참일 때만 보입니다
+dialog/schema/field/option_if = 표시 조건
+dialog/schema/builtin/option_if_desc = 예: archetype(rogue) 또는 "stat(cha) >= 5". 비우면 항상

locale/schema_ru.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = Реплика
+dialog/schema/builtin/text_desc = Строка диалога; ключ перевода — по желанию
+dialog/schema/field/text = Текст
+dialog/schema/field/locale_key = Ключ перевода
+dialog/schema/builtin/ptext = Повествование
+dialog/schema/builtin/ptext_desc = Текст рассказчика, подставляет ${var}
+dialog/schema/builtin/flag = Флаг сюжета
+dialog/schema/builtin/flag_desc = Сохраняемая отметка, по ней срабатывают условия
+dialog/schema/field/flag = Флаг
+dialog/schema/field/value = Значение
+dialog/schema/builtin/switch_scene = Сменить сцену
+dialog/schema/builtin/switch_scene_desc = Сцена новеллы или карта — карта тоже сцена
+dialog/schema/field/scene = Сцена
+dialog/schema/builtin/goto = Перейти к метке
+dialog/schema/builtin/goto_desc = Безусловный переход
+dialog/schema/field/label = Метка
+dialog/schema/builtin/end = Конец диалога
+dialog/schema/builtin/end_desc = Закрывает окно диалога
+dialog/schema/checks/when = Если — переход
+dialog/schema/checks/when_desc = Условный переход по общему языку условий: флаги, квесты, статы, снаряжение
+dialog/schema/checks/arrow_true = Если верно — метка
+dialog/schema/field/condition = Условие
+dialog/schema/field/else = Иначе — метка
+dialog/schema/builtin/select = Выбор
+dialog/schema/builtin/select_desc = Вопрос перед вариантами ответа; дальше идут строки option
+dialog/schema/builtin/option = Вариант ответа
+dialog/schema/builtin/option_desc = Вариант выбора и метка, куда он ведёт; с условием — показывается, только пока оно верно
+dialog/schema/field/option_if = Показывать, если
+dialog/schema/builtin/option_if_desc = Например archetype(rogue) или "stat(cha) >= 5"; пусто — всегда

locale/schema_vi.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = Lời thoại
+dialog/schema/builtin/text_desc = Một dòng hội thoại; khóa dịch tùy chọn
+dialog/schema/field/text = Văn bản
+dialog/schema/field/locale_key = Khóa dịch
+dialog/schema/builtin/ptext = Lời dẫn
+dialog/schema/builtin/ptext_desc = Lời người kể, điền ${var}
+dialog/schema/builtin/flag = Cờ cốt truyện
+dialog/schema/builtin/flag_desc = Một dấu được lưu, điều kiện sẽ phản ứng theo
+dialog/schema/field/flag = Cờ
+dialog/schema/field/value = Giá trị
+dialog/schema/builtin/switch_scene = Chuyển cảnh
+dialog/schema/builtin/switch_scene_desc = Cảnh tiểu thuyết hoặc bản đồ — bản đồ cũng là cảnh
+dialog/schema/field/scene = Cảnh
+dialog/schema/builtin/goto = Đến nhãn
+dialog/schema/builtin/goto_desc = Bước nhảy vô điều kiện
+dialog/schema/field/label = Nhãn
+dialog/schema/builtin/end = Kết thúc hội thoại
+dialog/schema/builtin/end_desc = Đóng hộp hội thoại
+dialog/schema/checks/when = Nếu — nhảy
+dialog/schema/checks/when_desc = Bước nhảy có điều kiện theo ngôn ngữ điều kiện chung: cờ, nhiệm vụ, chỉ số, trang bị
+dialog/schema/checks/arrow_true = Nếu đúng, đến
+dialog/schema/field/condition = Điều kiện
+dialog/schema/field/else = Nhãn nếu không
+dialog/schema/builtin/select = Lựa chọn
+dialog/schema/builtin/select_desc = Câu hỏi trước các đáp án; sau đó là các dòng option
+dialog/schema/builtin/option = Đáp án
+dialog/schema/builtin/option_desc = Một đáp án và nhãn nó dẫn tới; có điều kiện thì chỉ hiện khi điều kiện đúng
+dialog/schema/field/option_if = Hiện nếu
+dialog/schema/builtin/option_if_desc = Ví dụ archetype(rogue) hoặc "stat(cha) >= 5"; để trống — luôn hiện

locale/schema_zh.properties

@@ -0,0 +1,29 @@
+dialog/schema/builtin/text = 台词
+dialog/schema/builtin/text_desc = 一句对白；翻译键可选
+dialog/schema/field/text = 文本
+dialog/schema/field/locale_key = 翻译键
+dialog/schema/builtin/ptext = 旁白
+dialog/schema/builtin/ptext_desc = 旁白文本，会代入 ${var}
+dialog/schema/builtin/flag = 剧情标记
+dialog/schema/builtin/flag_desc = 会被保存的标记，条件据此触发
+dialog/schema/field/flag = 标记
+dialog/schema/field/value = 数值
+dialog/schema/builtin/switch_scene = 切换场景
+dialog/schema/builtin/switch_scene_desc = 小说场景或地图——地图也是场景
+dialog/schema/field/scene = 场景
+dialog/schema/builtin/goto = 跳到标签
+dialog/schema/builtin/goto_desc = 无条件跳转
+dialog/schema/field/label = 标签
+dialog/schema/builtin/end = 结束对话
+dialog/schema/builtin/end_desc = 关闭对话框
+dialog/schema/checks/when = 如果——跳转
+dialog/schema/checks/when_desc = 依据通用条件语言的条件跳转：标记、任务、属性、装备
+dialog/schema/checks/arrow_true = 为真时跳转
+dialog/schema/field/condition = 条件
+dialog/schema/field/else = 否则跳转
+dialog/schema/builtin/select = 选择
+dialog/schema/builtin/select_desc = 回答前的问题；后面跟着 option 行
+dialog/schema/builtin/option = 回答选项
+dialog/schema/builtin/option_desc = 一个回答及其跳转标签；带条件时仅在条件成立时显示
+dialog/schema/field/option_if = 显示条件
+dialog/schema/builtin/option_if_desc = 例如 archetype(rogue) 或 "stat(cha) >= 5"；留空——总是显示

schemas/dialog_base.json

@@ -0,0 +1,164 @@
+{
+  "Commands": [
+    {
+      "Id": "text",
+      "Name": "dialog/schema/builtin/text",
+      "Description": "dialog/schema/builtin/text_desc",
+      "Category": "dialog",
+      "Positional": [
+        {
+          "Key": "text",
+          "Type": "text",
+          "Required": true,
+          "Name": "dialog/schema/field/text"
+        }
+      ],
+      "Params": [
+        {
+          "Key": "key",
+          "Type": "text",
+          "Name": "dialog/schema/field/locale_key"
+        }
+      ]
+    },
+    {
+      "Id": "ptext",
+      "Name": "dialog/schema/builtin/ptext",
+      "Description": "dialog/schema/builtin/ptext_desc",
+      "Category": "dialog",
+      "Positional": [
+        {
+          "Key": "text",
+          "Type": "text",
+          "Required": true,
+          "Name": "dialog/schema/field/text"
+        }
+      ],
+      "Params": [
+        {
+          "Key": "key",
+          "Type": "text",
+          "Name": "dialog/schema/field/locale_key"
+        }
+      ]
+    },
+    {
+      "Id": "flag",
+      "Name": "dialog/schema/builtin/flag",
+      "Description": "dialog/schema/builtin/flag_desc",
+      "Category": "flow",
+      "Positional": [
+        {
+          "Key": "name",
+          "Type": "flag",
+          "Required": true,
+          "Name": "dialog/schema/field/flag"
+        },
+        {
+          "Key": "value",
+          "Type": "text",
+          "Required": true,
+          "Default": "1",
+          "Name": "dialog/schema/field/value"
+        }
+      ]
+    },
+    {
+      "Id": "switch_scene",
+      "Name": "dialog/schema/builtin/switch_scene",
+      "Description": "dialog/schema/builtin/switch_scene_desc",
+      "Category": "flow",
+      "Positional": [
+        {
+          "Key": "scene",
+          "Type": "scene",
+          "Required": true,
+          "Name": "dialog/schema/field/scene"
+        }
+      ]
+    },
+    {
+      "Id": "goto",
+      "Name": "dialog/schema/builtin/goto",
+      "Description": "dialog/schema/builtin/goto_desc",
+      "Category": "flow",
+      "Arrow": "dialog/schema/field/label"
+    },
+    {
+      "Id": "end",
+      "Name": "dialog/schema/builtin/end",
+      "Description": "dialog/schema/builtin/end_desc",
+      "Category": "flow"
+    },
+    {
+      "Id": "when",
+      "Name": "dialog/schema/checks/when",
+      "Description": "dialog/schema/checks/when_desc",
+      "Category": "flow",
+      "Arrow": "dialog/schema/checks/arrow_true",
+      "Positional": [
+        {
+          "Key": "condition",
+          "Type": "condition",
+          "Required": true,
+          "Name": "dialog/schema/field/condition"
+        }
+      ],
+      "Params": [
+        {
+          "Key": "else",
+          "Type": "label",
+          "Name": "dialog/schema/field/else"
+        }
+      ]
+    },
+    {
+      "Id": "select",
+      "Name": "dialog/schema/builtin/select",
+      "Description": "dialog/schema/builtin/select_desc",
+      "Category": "dialog",
+      "Positional": [
+        {
+          "Key": "text",
+          "Type": "text",
+          "Name": "dialog/schema/field/text"
+        }
+      ],
+      "Params": [
+        {
+          "Key": "key",
+          "Type": "text",
+          "Name": "dialog/schema/field/locale_key"
+        }
+      ]
+    },
+    {
+      "Id": "option",
+      "Name": "dialog/schema/builtin/option",
+      "Description": "dialog/schema/builtin/option_desc",
+      "Category": "dialog",
+      "Arrow": "dialog/schema/field/label",
+      "Positional": [
+        {
+          "Key": "text",
+          "Type": "text",
+          "Required": true,
+          "Name": "dialog/schema/field/text"
+        }
+      ],
+      "Params": [
+        {
+          "Key": "key",
+          "Type": "text",
+          "Name": "dialog/schema/field/locale_key"
+        },
+        {
+          "Key": "if",
+          "Type": "condition",
+          "Name": "dialog/schema/field/option_if",
+          "Description": "dialog/schema/builtin/option_if_desc"
+        }
+      ]
+    }
+  ]
+}

src/Scenarios/Impls/WhenCommandStrategy.cs

@@ -0,0 +1,43 @@
+namespace Cthangover.Mods.Dialog.Scenarios
+{
+    using System.Collections.Generic;
+    using Cthangover.Core.Localization;
+    using Cthangover.Core.Scenes;
+    using Cthangover.Mods.Dialog;
+
+    /// <summary>
+    /// A conditional jump in the middle of a dialog:
+    /// <code>when "stat(cha) &gt;= 5 &amp;&amp; door == 'open'" -> :persuaded [else=refused]</code>
+    /// evaluates the shared condition language (flags, quests, stats, equipment, GDScript
+    /// conditions — everything mods registered) at the moment the line runs, and jumps to
+    /// the arrow label when it holds, to <c>else</c> when it does not (or goes on).
+    /// <para/>
+    /// It is the RPG Maker "Conditional Branch" without a new syntax: the condition is the
+    /// same text a scenario header's <c>condition:</c> takes. Several words without quotes
+    /// are joined back with spaces, so short conditions need no quotes.
+    /// </summary>
+    public class WhenCommandStrategy : IScenarioCommandStrategy, IScenarioCommandSpec
+    {
+        /// <inheritdoc />
+        public string Command => "when";
+
+        /// <inheritdoc />
+        public int MinPositional => 1;
+
+        /// <inheritdoc />
+        public IReadOnlyList<string> AllowedNamed => new[] { "else" };
+
+        /// <inheritdoc />
+        public string JumpTargetNamedKey => "else";
+
+        /// <inheritdoc />
+        public void Execute(DialogQueue dlg, List<string> positional, Dictionary<string, string> named, string arrowTarget, ILocalizationProvider locale)
+        {
+            var condition = string.Join(" ", positional);
+            named.TryGetValue("else", out var otherwise);
+            dlg.IfGoTo(() => ScenarioCondition.Evaluate(condition), Label(arrowTarget), Label(otherwise));
+        }
+
+        private static string Label(string target) => string.IsNullOrWhiteSpace(target) ? null : target.Trim().TrimStart(':');
+    }
+}

src/Scenarios/ScenarioParser.cs

@@ -103,7 +103,10 @@ namespace Cthangover.Mods.Dialog.Scenarios
 
                     if (pendingSelect.Variants == null)
                         pendingSelect.Variants = new List<SelectVariant>();
-                    pendingSelect.Variants.Add(SelectVariant.New(optText, goTo));
+                    var variant = SelectVariant.New(optText, goTo);
+                    if (named.TryGetValue("if", out var condition))
+                        variant.Condition = condition;
+                    pendingSelect.Variants.Add(variant);
                     continue;
                 }
 

src/UI/Dialog/Action/Impls/ActionSelect.cs

@@ -1,4 +1,6 @@
 using System.Collections.Generic;
+using System.Linq;
+using Cthangover.Core.Utils;
 using Cthangover.Mods.Dialog.Action;
 using Godot;
 using Cthangover.Core.UI;
@@ -35,16 +37,29 @@ namespace Cthangover.Mods.Dialog.Action.Impls
         public override WaitType WaitType { get; set; } = WaitType.WaitSelect;
 
         /// <summary>Substitutes variables in the variants and context text, then shows the answer box; the runtime stays paused until a variant is picked.</summary>
+        /// <summary>
+        /// Offers the options whose conditions hold now. When none does, the choice is
+        /// skipped and the dialog goes on with the next line, so a choice of only gated
+        /// options never leaves the player stuck.
+        /// </summary>
         public override void DoRun(DialogRuntime runtime)
         {
             var dialogBox = runtime.DialogBox;
             if (dialogBox == null)
                 return;
 
-            foreach (var variant in Variants)
+            var shown = Variants.Where(v => v.IsShown()).ToList();
+            WaitType = shown.Count == 0 ? WaitType.NoWait : WaitType.WaitSelect;
+            if (shown.Count == 0)
+            {
+                GameLogger.Log("DIALOG", "select: no option is shown (all conditions false), going on", LogLevel.Debug);
+                return;
+            }
+
+            foreach (var variant in shown)
                 variant.Text = runtime.ProcessText(variant.Text);
 
-            dialogBox.SetVariants(Variants);
+            dialogBox.SetVariants(shown);
             dialogBox.SetText(runtime.ProcessText(Text));
         }
     }

src/UI/Dialog/Action/Impls/SelectVariant.cs

@@ -23,6 +23,16 @@ namespace Cthangover.Mods.Dialog.Action.Impls
         /// <summary>Target action ID to jump to via <see cref="DialogRuntime.TryGoTo"/> when this variant is selected.</summary>
         public string GoTo { get; set; }
 
+        /// <summary>
+        /// Condition of the shared condition language (<c>option "…" if=… -> :label</c>); the
+        /// option is shown only while it holds. Null = always shown. Evaluated each time the
+        /// choice appears, so a stat, a flag or an item gained a moment ago counts.
+        /// </summary>
+        public string Condition { get; set; }
+
+        /// <summary>Whether the option is offered now.</summary>
+        public bool IsShown() => string.IsNullOrWhiteSpace(Condition) || ScenarioCondition.Evaluate(Condition);
+
         /// <summary>Generates a new unique action ID for use as a GoTo target (e.g. with <see cref="DialogQueue.Point"/>).</summary>
         public static string Point => Guid.NewGuid().ToString();
 

tests/OptionConditionTests.cs

@@ -0,0 +1,59 @@
+namespace Cthangover.Mods.Dialog.Tests
+{
+    using System.Linq;
+    using System.Threading.Tasks;
+    using Cthangover.Core.Mods.Testing;
+    using Cthangover.Mods.Dialog.Action.Impls;
+    using Cthangover.Mods.Dialog.Scenarios;
+
+    /// <summary>
+    /// <c>option … if=…</c>: an option is offered only while its condition holds; a choice whose
+    /// options are all hidden is skipped, so the dialog never waits for an answer nobody can give.
+    /// </summary>
+    public class OptionConditionTests
+    {
+        [ModTest("options/parser_keeps_the_condition")]
+        static void ParserKeepsTheCondition(ModTestContext ctx)
+        {
+            var dlg = ScenarioParser.Parse("select \"?\"\noption \"A\" -> :a\noption \"B\" \"if=door == 'open' && !false\" -> :b\n:a\nend\n:b\nend\n");
+            var select = dlg.Queue.OfType<ActionSelect>().Single();
+            ModAssert.Null(select.Variants[0].Condition, "a plain option has no condition");
+            ModAssert.Equal("door == 'open' && !false", select.Variants[1].Condition, "the quoted pair keeps spaces");
+            ModAssert.Equal("b", select.Variants[1].GoTo, "the jump target stays");
+        }
+
+        [ModTest("options/hidden_options_are_not_offered", TimeoutSeconds = 10)]
+        static async Task HiddenOptionsAreNotOffered(ModTestContext ctx)
+        {
+            var stage = await DialogStage.Create();
+            try
+            {
+                var dlg = ScenarioParser.Parse("select \"?\"\noption \"A\" if=false -> :a\noption \"B\" if=true -> :b\noption \"C\" -> :c\n:a\nend\n:b\nend\n:c\nend\n");
+                ModAssert.True(stage.Box.SetDialogQueueAndRun(dlg, null, 0, null), "dialog starts");
+                ModAssert.True(stage.Box.IsWaitingAnswer, "waits for an answer");
+                ModAssert.Equal(2, stage.Box.AnswerVariantCount, "the false option is hidden");
+            }
+            finally
+            {
+                stage.Free();
+            }
+        }
+
+        [ModTest("options/all_hidden_skips_the_choice", TimeoutSeconds = 10)]
+        static async Task AllHiddenSkipsTheChoice(ModTestContext ctx)
+        {
+            var stage = await DialogStage.Create();
+            try
+            {
+                var dlg = ScenarioParser.Parse("select \"?\"\noption \"A\" if=false -> :a\n\nset outcome skipped\nend\n:a\nset outcome a\nend\n");
+                stage.Box.SetDialogQueueAndRun(dlg, null, 0, null);
+                ModAssert.False(stage.Box.IsWaitingAnswer, "no answer is awaited");
+                ModAssert.Equal("skipped", stage.Box.Runtime.GetVariable("outcome"), "the dialog went on past the choice");
+            }
+            finally
+            {
+                stage.Free();
+            }
+        }
+    }
+}

tests/WhenCommandStrategyTests.cs

@@ -0,0 +1,42 @@
+namespace Cthangover.Mods.Dialog.Tests
+{
+    using Cthangover.Core.Mods.Testing;
+    using Cthangover.Core.Scenes;
+    using Cthangover.Mods.Dialog.Scenarios;
+
+    /// <summary><c>when</c> jumps on the shared condition language, evaluated when the line runs.</summary>
+    public class WhenCommandStrategyTests
+    {
+        private static string Outcome(string scenario)
+        {
+            var dlg = ScenarioParser.Parse(scenario);
+            var runtime = new DialogRuntime();
+            runtime.SetDialogQueueAndRun(null, dlg.Queue, null);
+            runtime.Run();
+            return runtime.GetVariable("outcome");
+        }
+
+        [ModTest("when/true_false_and_else")]
+        static void TrueFalseAndElse(ModTestContext ctx)
+        {
+            ModAssert.Equal("yes", Outcome("when true -> :yes\nset outcome no\nend\n:yes\nset outcome yes\nend\n"), "true jumps");
+            ModAssert.Equal("no", Outcome("when false -> :yes\nset outcome no\nend\n:yes\nset outcome yes\nend\n"), "false falls through");
+            ModAssert.Equal("other", Outcome("when false -> :yes else=other\nset outcome no\nend\n:yes\nset outcome yes\nend\n:other\nset outcome other\nend\n"), "false takes else");
+        }
+
+        [ModTest("when/reads_state_when_the_line_runs")]
+        static void ReadsStateWhenTheLineRuns(ModTestContext ctx)
+        {
+            ScenarioCondition.SetFlag("test_when_flag", "0");
+            try
+            {
+                const string scenario = "flag test_when_flag 2\nwhen \"test_when_flag >= 2 && !false\" -> :yes\nset outcome no\nend\n:yes\nset outcome yes\nend\n";
+                ModAssert.Equal("yes", Outcome(scenario), "a flag set two lines earlier counts");
+            }
+            finally
+            {
+                ScenarioCondition.SetFlag("test_when_flag", "0");
+            }
+        }
+    }
+}