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update README to include information on high performance

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Nathan Marz 2015-05-11 15:19:20 -04:00
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README.md
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# Specter # Specter
Deep introspection and transformation of nested data
# About Most of Clojure programming involves creating, manipulating, and transforming immutable values. However, as soon as your values become more complicated than a simple map or list – like a list of maps of maps – transforming these data structures becomes extremely cumbersome.
Specter is a library for concisely querying and updating nested data structures. One way to think of it is "get-in" and "assoc-in" on steroids, though Specter works on any data structure, not just maps. It is similar to the concept of a "lens" in functional programming, though it has some important extensions. Specter is a library for querying and updating nested data structures. One way to think of it is "get-in" and "assoc-in" on steroids, though Specter works on any data structure, not just maps. It is similar to the concept of a "lens" in functional programming, though it has some important extensions.
Specter is a very high performance library. For example – the Specter equivalent to get-in runs 30% faster than get-in, and the Specter equivalent to update-in runs 5x faster than update-in. In each case the Specter code is equally as convenient.
# Latest Version # Latest Version
@ -106,7 +107,7 @@ To make your own selector, implement the `StructurePath` protocol which looks li
Looking at the implementations of the built-in selectors should provide you with the guidance you need to make your own selectors. Looking at the implementations of the built-in selectors should provide you with the guidance you need to make your own selectors.
Finally, you can make `select` and `update` work much faster by precompiling your selectors using the `comp-paths` function. There's about a 10x speed difference between the following two invocations of update: Finally, you can make `select` and `update` work much faster by precompiling your selectors using the `comp-paths` function. There's about a 3x speed difference between the following two invocations of update:
```clojure ```clojure
(def precompiled (comp-paths ALL :a even?)) (def precompiled (comp-paths ALL :a even?))
@ -115,6 +116,8 @@ Finally, you can make `select` and `update` work much faster by precompiling you
(update precompiled inc structure) (update precompiled inc structure)
``` ```
Depending on the details of the selector and the data being transformed, precompiling can sometimes provide more than a 10x speedup.
Some more examples: Some more examples:
Decrement every value in a map: Decrement every value in a map: