Justification for this feature is added in the docs.
Precedent for the precise syntax: Hugo.
Hugo puts this syntax behind a preference named headerIds, and automatic
header ID generation behind a preference named autoHeaderIds, with both
enabled by default. I have not implemented a switch to disable this.
My suggestion for a workaround for the improbable case of desiring a
literal “{#…}” at the end of a header is to replace `}` with `}`.
The algorithm I have used is not identical to [that
which Hugo uses][0], because Hugo’s looks to work at the source level,
whereas here we work at the pulldown-cmark event level, which is
generally more sane, but potentially limiting for extremely esoteric
IDs.
Practical differences in implementation from Hugo (based purely on
reading [blackfriday’s implementation][0], not actually trying it):
- I believe Hugo would treat `# Foo {#*bar*}` as a heading with text
“Foo” and ID `*bar*`, since it is working at the source level; whereas
this code turns it into a heading with HTML `Foo {#<em>bar</em>}`, as
it works at the pulldown-cmark event level and doesn’t go out of its
way to make that work (I’m not familiar with pulldown-cmark, but I get
the impression that you could make it work Hugo’s way on this point).
The difference should be negligible: only *very* esoteric hashes would
include magic Markdown characters.
- Hugo will automatically generate an ID for `{#}`, whereas what I’ve
coded here will yield a blank ID instead (which feels more correct to
me—`None` versus `Some("")`, and all that).
In practice the results should be identical.
Fixes#433.
[0]: a477dd1646/block.go (L218-L234)
This reverts commit 5fd7bf7e61.
Apparently it is not just no longer necessary to use classic
confinement, but actually impossible, i.e. snap emits an error that the
zola snap is not compatible with `--classic`.
