"Pattern Matching" When Rendering Views in Rails
What's Pattern Matching?
Pattern matching is a useful feature provided by many programming
languages. It can help because it reduces conditional statements
if in our code and thus make our code more straightforward
and easier to understand.
Here is a quick example of pattern matching in Elixir:
def string_based_on_locale("en") do "Hello, World!" end def string_based_on_locale("zh") do "你好，世界！" end
Usage in Rails View Rendering
Pattern matching is so powerful that I even applied it unconsciously when I worked in a Ruby/Rails app after I've dived into Elixir/Phoenix world for some time.
Here is the case:
- The app support two locales: English and Chinese.
- And there are some UI differences other than translations in these two versions.
An example is navbar dropdown. So I turned dropdown into two partials:
dropdown_en.html.slim. Then render one of them based on current locale:
After I've written this code, I realized this is exactly like a pattern matching. In Elixir, I would write:
def render_dropdown("zh") do end def render_dropdown("en") do end
- Of course, this is a basic case for pattern matching. And
Ruby and Rails still don't more advanced pattern matching. But
it's still useful enough to show some strength:
We don't need
if I18n.locale == "zh" # ... else # ... end
- If we want to add a dropdown for a new locale, we just add a
new template named after that locale, say
Pattern matching is a language feature to achieve certain level of polymorphism. We can still use the same technique in Ruby/Rails even they don't provide such feature at language level. Let me know in the comments below if you know any example like this.