Hash: Wrapper so diagrams can be inserted and repointed from the visual editor: the page name becomes a parameter rather than a parser-function target

2026-09-11T05:09:23Z

Wrapper so diagrams can be inserted and repointed from the visual editor: the page name becomes a parameter rather than a parser-function target

New page

<noinclude>
Embeds a diagram that lives on its own page in one of the five diagram namespaces, so it can be inserted and repointed from the visual editor.

'''Usage:''' <code><nowiki>{{Diagram|page=Mermaid:RE FlowChart Overview}}</nowiki></code>

The <code>page</code> parameter is the full page name of the diagram, ''including'' its namespace prefix — <code>Mermaid:</code>, <code>DOT:</code>, <code>Drawio:</code>, <code>BPMN:</code> or <code>Gantt:</code>. See [[Help:Diagrams]].

This template wraps the <code><nowiki>{{#display_diagram:}}</nowiki></code> parser function. The wrapper exists so the diagram name is a ''parameter'': the visual editor can insert and change parameters, but has no way to edit a parser function's target, so a bare <code><nowiki>{{#display_diagram:}}</nowiki></code> call can only be changed by editing the page source. Bare calls still work and still render — prefer this template for anything new.

The <code><nowiki>{{#if:}}</nowiki></code> guard below is load-bearing: <code>FDDisplayDiagram::run()</code> passes its argument to <code>Title::newFromText()</code> and calls <code>->exists()</code> on the result without a null check, so an empty <code>page</code> would throw a fatal error rather than render nothing.

<templatedata>
{
"description": "Embed a diagram from the Mermaid, DOT, Drawio, BPMN or Gantt namespace.",
"params": {
"page": {
"label": "Diagram page",
"description": "Full page name of the diagram, including the namespace prefix, e.g. Mermaid:RE FlowChart Overview",
"example": "Mermaid:RE FlowChart Overview",
"type": "wiki-page-name",
"required": true,
"suggested": true
}
},
"paramOrder": [
"page"
],
"format": "inline"
}
</templatedata>
</noinclude><includeonly>{{#if:{{{page|}}}|{{#display_diagram:{{{page|}}}}}|}}</includeonly>

Template:Diagram - Revision history

Hash: Wrapper so diagrams can be inserted and repointed from the visual editor: the page name becomes a parameter rather than a parser-function target