uc-clojure is my interpretation of Tom Stuart's "Understanding Computation" code, translated to Clojure.
In your REPL-integrated editor of choice, run any of the expressions in small_step_fiddle.clj.
Alternatively, open up a REPL and require uc-clojure.small-step:
$ clj user=> (require '[uc-clojure.small-step :refer :all])
Get a vector of the small steps of a machine as it performs a reduction on its expression or statement. Each step is a 2-item vector consisting of the string representation of an expression/statement and the current environment as a map:
user=> (run machine-1)
[["1 * 2 + 3 * 4" {}] ["2 + 3 * 4" {}] ["2 + 12" {}] ["14" {}]]
Pretty-print the derivation/reduction of a machine:
user=> (run-print machine-1)
1 * 2 + 3 * 4, {}
2 + 3 * 4, {}
2 + 12, {}
14, {}
Get the return value (last step) of a machine:
user=> (get-ret machine-1)
["14" {}]
Copyright © 2019 Joel Dunham
This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at http://www.eclipse.org/legal/epl-2.0.
This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.