Implicit short title, disabled by default

fixtures/local/magic_ImplicitShortTitle.txt

@@ -0,0 +1,76 @@
+>>===== MODE =====>>
+citation
+<<===== MODE =====<<
+
+>>===== OPTIONS =====>>
+{
+  "implicit_short_title": true
+}
+<<===== OPTIONS =====<<
+
+
+>>===== RESULT =====>>
+My title?
+My title!
+My title
+<<===== RESULT =====<<
+
+
+>>===== CITATION-ITEMS =====>>
+[
+  [
+    {
+      "id": "ITEM-1"
+    }
+  ],
+  [
+    {
+      "id": "ITEM-2"
+    }
+  ],
+  [
+    {
+      "id": "ITEM-3"
+    }
+  ]
+]
+<<===== CITATION-ITEMS =====<<
+
+>>===== CSL =====>>
+<style 
+      xmlns="http://purl.org/net/xbiblio/csl"
+      class="note"
+      version="1.0"
+      default-locale="en-x-translit-ja">
+  <info>
+    <id />
+    <title />
+    <updated>2009-08-10T04:49:00+09:00</updated>
+  </info>
+  <citation>
+    <layout>
+      <text variable="title-short"/>
+    </layout>
+  </citation>
+</style>
+<<===== CSL =====<<
+
+>>===== INPUT =====>>
+[
+    {
+        "id": "ITEM-1", 
+        "type": "article-journal",
+        "title": "My title? yes, with a subtitle"
+    },
+    {
+        "id": "ITEM-2", 
+        "type": "article-journal",
+        "title": "My title! yes, with a subtitle"
+    },
+    {
+        "id": "ITEM-3", 
+        "type": "article-journal",
+        "title": "My title: yes, with a subtitle"
+    }
+]
+<<===== INPUT =====<<

src/build.js

@@ -95,7 +95,7 @@ CSL.Engine = function (sys, style, lang, forceLang) {
         }
 
     }
-    if (this.opt.development_extensions.uppercase_subtitles) {
+    if (this.opt.development_extensions.uppercase_subtitles || this.opt.development_extensions.implicit_short_title) {
         this.opt.development_extensions.main_title_from_short_title = true;
     }
     if (this.opt.development_extensions.csl_reverse_lookup_support) {

src/load.js

@@ -753,6 +753,15 @@ var CSL = {
                             vals[title.main] = splitTitle[0];
                             vals[title.subjoin] = splitTitle[1];
                             vals[title.sub] = splitTitle[2];
+                            if (this.opt.development_extensions.implicit_short_title) {
+                                if (!Item["title-short"]) {
+                                    var punct = vals[title.subjoin].trim();
+                                    if (["?", "!"].indexOf(punct) === -1) {
+                                        punct = "";
+                                    }
+                                    vals[title["short"]] = vals[title.main] + punct;
+                                }
+                            }
                         } else {
                             vals[title.main] = vals[title.title];
                             vals[title.subjoin] = "";
@@ -1183,7 +1192,8 @@ var CSL = {
         "csl_reverse_lookup_support",
         "main_title_from_short_title",
         "uppercase_subtitles",
-        "force_short_title_casing_alignment"
+        "force_short_title_casing_alignment",
+        "implicit_short_title"
     ],
 
     TITLE_SPLIT_REGEXP: (function() {

src/state.js

@@ -165,6 +165,7 @@ CSL.Engine.Opt = function () {
     this.development_extensions.strict_inputs = true;
     this.development_extensions.prioritize_disambiguate_condition = false;
     this.development_extensions.force_short_title_casing_alignment = true;
+    this.development_extensions.implicit_short_title = false;
 };
 
 CSL.Engine.Tmp = function () {