Skip to content
Guides by jbrains

Use Explicit Namespaces

Including library files feels like copy and paste with extra steps. It allows you to move quickly at the beginning, but eventually you start to notice that you struggle to understand where code came from, which means struggling to find things when you look for them. Yes, grep and its cousins help, but it feels better to have an idea what’s what and where it came from. Namespaces help.

From Libraries to Modules

When you include code from library files, you can turn them into modules imported into namespaces with just a dash of extra code. It’s never worth the effort until it very suddenly is.

Terminal window
echo "\"CAD 175.62\"" | jq -L "assets/jq" 'import "parsing" as Parsing; Parsing::parse_monetary_amount'

We have done this:

  • Replaced include with import.
  • Specified the namespace Parsing when we import "parsing".
  • Specified the namespace when we invoke the library function: Parsing::parse_monetary_amount.
  • Specified the library path so that jq can find the parsing module.

That’s enough! Now you can import functions from two libraries with the same name without a naming collision. There is a lot more to modules than this, as the jq manual explains, but frankly I haven’t yet needed to know any more than what you’ve seen here. This is truly enough.