The main motivation behind this is simplicity and correctnes, but the new small config library is also faster:
```
BenchmarkDefaultConfigProvider/Viper-16 252418 4546 ns/op 2720 B/op 30 allocs/op
BenchmarkDefaultConfigProvider/Custom-16 450756 2651 ns/op 1008 B/op 6 allocs/op
```
Fixes#8633Fixes#8618Fixes#8630
Updates #8591Closes#6680Closes#5192
This commit adds support for theme composition and inheritance in Hugo.
With this, it helps thinking about a theme as a set of ordered components:
```toml
theme = ["my-shortcodes", "base-theme", "hyde"]
```
The theme definition example above in `config.toml` creates a theme with the 3 components with presedence from left to right.
So, Hugo will, for any given file, data entry etc., look first in the project, and then in `my-shortcode`, `base-theme` and lastly `hyde`.
Hugo uses two different algorithms to merge the filesystems, depending on the file type:
* For `i18n` and `data` files, Hugo merges deeply using the translation id and data key inside the files.
* For `static`, `layouts` (templates) and `archetypes` files, these are merged on file level. So the left-most file will be chosen.
The name used in the `theme` definition above must match a folder in `/your-site/themes`, e.g. `/your-site/themes/my-shortcodes`. There are plans to improve on this and get a URL scheme so this can be resolved automatically.
Also note that a component that is part of a theme can have its own configuration file, e.g. `config.toml`. There are currently some restrictions to what a theme component can configure:
* `params` (global and per language)
* `menu` (global and per language)
* `outputformats` and `mediatypes`
The same rules apply here: The left-most param/menu etc. with the same ID will win. There are some hidden and experimental namespace support in the above, which we will work to improve in the future, but theme authors are encouraged to create their own namespaces to avoid naming conflicts.
A final note: Themes/components can also have a `theme` definition in their `config.toml` and similar, which is the "inheritance" part of this commit's title. This is currently not supported by the Hugo theme site. We will have to wait for some "auto dependency" feature to be implemented for that to happen, but this can be a powerful feature if you want to create your own theme-variant based on others.
Fixes#4460Fixes#4450
This means that you can do something ala:
```html
{{ if ge .Hugo.Version "0.36" }}Reasonable new Hugo version!{{ end }}
```
The intented use is feature toggling, but please note that it will take some time and Hugo versions until this can be trusted. It does not work in older Hugo versions.
Fixes#4443
This closes#98, even if this commit does not do full content text search.
We may revisit that problem in the future, but that deserves its own issue.
Fixes#98
All config variables starts with low-case and uses camelCase.
If there is abbreviation at the beginning of the name, the whole
abbreviation will be written in low-case.
If there is abbreviation at the end of the name, the
whole abbreviation will be written in upper-case.
For example, rssURI.
The gain, given the "real sites benchmark" below, is obvious:
```
benchmark old ns/op new ns/op delta
BenchmarkHugo-4 14497594101 13084156335 -9.75%
benchmark old allocs new allocs delta
BenchmarkHugo-4 57404335 48282002 -15.89%
benchmark old bytes new bytes delta
BenchmarkHugo-4 9933505624 9721984424 -2.13%
```
Fixes#2495
Put version handling into the helpers package so it can be used by many,
and split version and suffix to make it possible to calculate the next Hugo version.
Bjørn Erik Pedersen