#31011: A new template tag for ternary operations?
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Reporter: lapinvert | Owner: nobody
Type: New feature | Status: new
Component: Uncategorized | Version: 2.2
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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I am aware that this issue was already pointed out
[https://code.djangoproject.com/ticket/14333 here], but it was 9 years
ago, so I allowed myself to bring it back again.
HTML easily gets complex and nested, and in many case you don't want to
add to this complexity and you need to add inline logic but you can't do
that in Django without a lot of verbosity.
Django's PHP competitor `Laravel` manages template with something called
`Blade`, in which inserting a one-line condition looks like:
`{{ condition ? var1 : var2 }}`
... which is the exact same syntaxe as many major JavaScript-based
frontend frameworks (Vue / React...).
Rails's templating engine `ERB` also provides a similar syntaxe:
`<%= condition? ? var1 : var2 %>`
I also remember one of my projects in Angular 1, where I was even able to
use a filter on the output of it:
`{{ condition ? date1 : date2 | dateFilter }}`
(and also have space around the filter for better readability, but that's
another topic... `Sparse is better than dense`)
In Django that would translate in:
`{% if condition %}{{ date1|date:'c' }}{% else %}{{ date2|date:'c' }}{%
endif %}`
That is... pretty verbose. Especially if you replace those placeholder
vars with actual (often longer) ones. In an actual project you often find
yourself violating in many ways the Zen of Python (flat vs nested,
readability, etc).
The other tools we have at our disposal is :
- The filter `|default:''` works fine in a lot of cases, but sometimes you
just need to check for a third parameter.
- The filter `|yesno:"yes,no"` however this works only for displaying
strings.
**Possible solution**
Well, the point is not to say that Django should allow the exact same
syntaxe as other languages, but at least I think it should allow some sort
of natively supported ternary operation.
I suggest to keep the pythonic way of writing a ternary operation and
implement it within Django template. Example:
`{% ternary var1 if condition else var2 %}`
Currently:
`{% if condition %}{{ var1 }}{% else %}{{ var2 }}{% endif %}`
Given the arbitrary "ternary" wording, this is `{% ternary if else %}`
vs `{% if %}{{ }}{% else %}{{ }}{% endif %}`. 43 chars -> 25 chars
(about 43% reduction).
**Final thoughts**
If this is to be resolved as `wontfix` again, would it be possible to at
least explain a clear and practical reason as for why we don't want to
include a native ternary operation in Django templates, where virtually
every other languages and frameworks do include one? (`python`,
`JavaScript`, `Rails`, `Laravel` ...)
--
Ticket URL: <https://code.djangoproject.com/ticket/31011>
Django <https://code.djangoproject.com/>
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