slurp-or-evaluate

A Clojure library that allows you to easily save and restore values to and from file, intended to be used as part of a REPL-based development workflow.

There are two main uses:

• Save time by avoiding repeated re-computation of things that take a long time to compute.
• Save values obtained from online sources, allowing you to use those values when offline.

Usage

Basics

For a Leiningen project, use the following dependency:

[com.nomistech/slurp-or-evaluate "0.1.3"]

Add the following to your ns declaration:

(:require [com.nomistech.slurp-or-evaluate :refer :all])

Use as follows:

(def-expensive foo ...my-expensive-computation...)

This is the same as def, except:

• If def-expensive has a saved value, it will use that instead of evaluating ...my-expensive-computation....
• If def-expensive does not have a saved value, it will save the result of evaluating ...my-expensive-computation... to file for future use.

You can also have a doc string as follows:

(def-expensive foo "my doc string" ...my-expensive-computation...)

Storage Directory

slurp-or-evaluate stores data in the directory _slurp-or-evaluate-store/.

You may wish to exclude that directory from version control (e.g. add it to your .gitignore file).

Var Names

The name of the var being defined must be a valid filename on your system, because slurp-or-evaluate uses the name of the var as the name of the file in which to store the saved value (within the _slurp-or-evaluate-store/ directory).

Removing a Saved Value

To remove slurp-or-evaluate's saved value for a var, you can either remove its file from the _slurp-or-evaluate-store/ directory or you can use def-expensive-replacing to force an update.

A call of def-expensive-replacing would probably only exist temporarily — the idea is that you would change a call of def-expensive to a call of def-expensive-replacing, evaluate it, and then change it back.

Changing the Storage Directory

You can change where slurp-or-evaluate stores data with:

(alter-var-root #'slurp-or-evaluate-store-dir (constantly "my-store-dir"))

License

Copyright © 2016 Simon Katz

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.