[feature] Unfortunate HTML output template placeholder

[kvid]

HTML output templates with placeholders for generated text is a new feature introduced in v0.4. All placeholders are named <!-- %something% -->, except one placeholder called "sheetsize_default" only.

1. Why is it called sheetsize_default and not sheetsize or template_sheetsize? The replacement text is fetched from metadata.template.sheetsize.
2. Why is it not called <!-- %template_sheetsize% --> to be consistent with the other placeholders?
3. I guess the quote characters was needed to include in the search term to avoid false hits, and therefore re-inserted around the fetched value to keep the correct HTML syntax. This seems like a hack for this placeholder only, and would not be needed if using my suggestion in point 2 above. Then <!-- %template_sheetsize% --> could be placed within the quote characters in the template, but the quote characters need not be replaced, and special treatment of this placeholder is no longer needed. The code would be cleaner, and a documentation description would be easier to understand because all placeholders are treated equally.

I suggest replacing https://github.com/wireviz/WireViz/blob/v0.4/src/wireviz/wv_html.py#L104-L106 with a simple entry

        "<!-- %template_sheetsize% -->": metadata.get("template", {}).get("sheetsize", ""),

inserted together with the others at https://github.com/wireviz/WireViz/blob/v0.4/src/wireviz/wv_html.py#L88
and then update the placeholder to <!-- %template_sheetsize% --> in templates/din-6771.html

[martinrieder]

I propose to use the default placeholder pattern that is used in Jinja. It would allow using this as a templating engine that is much more powerful than the simple replacements that we are currently using:
Jinja Template Designer Documentation

Note that Jinja could also be used to generate the GV files from templates, though I would consider that a major change that is to be discussed separately.

[kvid]

@formatc1702 - Is my original issue here trivial, or might there be bad side-effects?

The suggestion by @martinrieder is also valid, but that must be handled later, in a separate issue.

[formatc1702]

TL;DR: it's debug legacy and can be changed.

The initial design of the technical drawing templates happened quite a while ago but I seem to recall the following reason:

Using sheetsize_default without any surrounding special characters allowed viewing the din-6771.html template file itself in the browser with no issues, while working on its layout and design. Placeholders using the HTML comment syntax <!-- --> simply show up as blanks, but using this syntax within the div's class attribute causes issues, thus sheetsize_default was chosen so it would resolve to a valid CSS class.

[kvid]

Closed after releasing v0.4.1.