Improve document.GetOption: Merge default and buffer local options

Unlike the other BufferSettings, #+OPTIONS: specifies multiple options and we
cannot just look it up in either BufferSettings or DefaultSettings - both have
to be checked

org/document.go

@@ -146,20 +146,27 @@ func (d *Document) Get(key string) string {
 
 // see https://orgmode.org/manual/Export-settings.html
 func (d *Document) GetOption(key string) bool {
-	for _, field := range strings.Fields(d.Get("OPTIONS")) {
+	get := func(settings map[string]string) string {
-		if strings.HasPrefix(field, key) {
+		for _, field := range strings.Fields(settings["OPTIONS"]) {
-			switch field[len(key)+len(":"):] {
+			if strings.HasPrefix(field, key+":") {
-			case "t":
+				return field[len(key)+1:]
-				return true
-			case "nil":
-				return false
-			default:
-				d.Log.Printf("Bad value for export option %s (%s)", key, field)
-				return false
 			}
 		}
+		return ""
+	}
+	value := get(d.BufferSettings)
+	if value == "" {
+		value = get(d.DefaultSettings)
+	}
+	switch value {
+	case "t":
+		return true
+	case "nil":
+		return false
+	default:
+		d.Log.Printf("Bad value for export option %s (%s)", key, value)
+		return false
 	}
-	return false
 }
 
 func (d *Document) parseOne(i int, stop stopFn) (consumed int, node Node) {

org/testdata/options.html

@@ -1,13 +1,15 @@
 <h1 id="headline-1">
-<code class="verbatim">#+OPTIONS:</code> toggles supported by <code class="verbatim">go-org</code>
+<span class="todo">DONE</span>
+<span class="priority">[A]</span>
+<code class="verbatim">#+OPTIONS:</code> toggles supported by <code class="verbatim">go-org</code>&#xa0;&#xa0;&#xa0;<span class="tags"><span>tag1</span>&#xa0;<span>tag2</span></span>
 </h1>
 <p>
-<code class="verbatim">go-org</code> supports multiple export toggles as described in the <a href="https://orgmode.org/manual/Export-settings.html">export settings</a> Org mode manual.
+<code class="verbatim">go-org</code> supports multiple export toggles as described in the <a href="https://orgmode.org/manual/Export-settings.html">export settings</a> section of the Org mode manual.
-By default those toggles are enabled. This files starts with <code class="verbatim">#+OPTIONS:</code> (empty options) and thus
+By default (most of?) those toggles are enabled. This file starts with <code class="verbatim">#+OPTIONS: toc:nil f:nil e:nil</code> and thus
-disables all settings.
+disables the table of contents, footnotes &amp; entities.
 That means, entities like <code class="verbatim">---</code> --- (mdash) will be left untouched, footnotes like <code class="verbatim">[fn:1]</code>  will
 not be exported and there won&#39;t be a table of contents at the top.
-Also, the above headline will be exported without priority, todo status &amp; tags.
+As buffer options are merged with the defaults, the above headline will be exported <strong>with</strong> priority, todo status &amp; tags.
 </p>
 <table>
 <thead>

org/testdata/options.org

@@ -1,12 +1,12 @@
-#+OPTIONS:
+#+OPTIONS: toc:nil f:nil e:nil
 
 * DONE [#A] =#+OPTIONS:= toggles supported by =go-org=                 :tag1:tag2:
-=go-org= supports multiple export toggles as described in the [[https://orgmode.org/manual/Export-settings.html][export settings]] Org mode manual.
+=go-org= supports multiple export toggles as described in the [[https://orgmode.org/manual/Export-settings.html][export settings]] section of the Org mode manual.
-By default those toggles are enabled. This files starts with =#+OPTIONS:= (empty options) and thus
+By default (most of?) those toggles are enabled. This file starts with =#+OPTIONS: toc:nil f:nil e:nil= and thus
-disables all settings.
+disables the table of contents, footnotes & entities.
 That means, entities like =---= --- (mdash) will be left untouched, footnotes like =[fn:1]= [fn:1] will
 not be exported and there won't be a table of contents at the top.
-Also, the above headline will be exported without priority, todo status & tags.
+As buffer options are merged with the defaults, the above headline will be exported *with* priority, todo status & tags.
 
 
 | key  | description                                               |

org/testdata/options.pretty_org

@@ -1,12 +1,12 @@
-#+OPTIONS:
+#+OPTIONS: toc:nil f:nil e:nil
 
 * DONE [#A] =#+OPTIONS:= toggles supported by =go-org=            :tag1:tag2:
-=go-org= supports multiple export toggles as described in the [[https://orgmode.org/manual/Export-settings.html][export settings]] Org mode manual.
+=go-org= supports multiple export toggles as described in the [[https://orgmode.org/manual/Export-settings.html][export settings]] section of the Org mode manual.
-By default those toggles are enabled. This files starts with =#+OPTIONS:= (empty options) and thus
+By default (most of?) those toggles are enabled. This file starts with =#+OPTIONS: toc:nil f:nil e:nil= and thus
-disables all settings.
+disables the table of contents, footnotes & entities.
 That means, entities like =---= --- (mdash) will be left untouched, footnotes like =[fn:1]= [fn:1] will
 not be exported and there won't be a table of contents at the top.
-Also, the above headline will be exported without priority, todo status & tags.
+As buffer options are merged with the defaults, the above headline will be exported *with* priority, todo status & tags.
 
 
 | key  | description                                               |