INXS

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Macros that make using interceptors easier without sacrificing callability.

📝 Table of Contents

• What is it?
• Why does it exist?
• What does it cost?
• How do I use it?
• Are there examples?
• Is it finished?
• How can I help?
• Did you show gratitude?

What is it?

It provides a few public functions.

• ixfn creates named functions from interceptors and interceptors from anonymous fns.
• ls-ixfn lists all interceptor fns on the classpath.
• exec runs a chain by first finding and hydrating the interceptors that are referenced by keywords.

Why does it exist?

Speed and ease for the user. It's a low-cost high-leverage change. It allows you to write interceptor fns as well construct chains and calls to chains without having to think about the system as a whole. Here are the benefits;

1. Interceptors and their non interceptor couterparts are one in the same. IXFNs are prefixed ixfn-your-symbol while plain fns are simply your-symbol. You use your-symbol like any other fn.
2. Interceptor namespaces do not need to be required to be used, they simply need to be present on the classpath.
3. Chains can be dynamically constructed via keywords and not symbols. This makes constructing chains programmatically at runtime dead simple.
4. Using the supplied exec fn an extra argument can be provided to control the return value. This extra argument is also simply a keyword to extract or a collection of keywords to use with select keys. This adds to the runtime dynamism of using INXS.

What does it cost?

This ease and speed doesn't come free. Here are the negatives;

1. ixfn is a macro.
2. CLJS does not have all-ns which makes crossplatform usage difficult since virtually all calls require an extra argument (all the namespaces to search for ixfns). Because it just became awkward writing/reading/using it this way, I eventually dropped CLJS support. This was a painful decision for me, but I'd rather enjoy developing on one platform than not enjoy two. I'm debating just using the macro in CLJS and not making the chain fn available, but for now in my personal use, I just don't have a reason to use interceptors in the browser.
3. Searching through all namespaces can be expensive in terms of time.

How do I use it?

Are there examples?

Is it finished?

Yes.

How can I help?

Use it, dream of a better future, and complain. This library does little and won't ever do much so...

Did you show gratitude?

Exoscale Interceptor - It's the simplest interceptor library out there. It does little, asks for little, and reliably does what it says.

Lambda Island Episode #32 - This was the first time it hit me that I could store the var itself in the metadata attached to a var. I've learned painfully not to overuse it, but it's still a powerfully simple way to do cool stuff.