LACE - Lab47 Accelerated Computing Environment

Lace is a clojure environment forked from https://github.com/candid82/joker and embued with enhanced powers, such as:

• A Bytecode VM to speed up interpretation
• Extensive interact with Go types
• Detailed stacktraces that can alternate between clojure code and Go code

Installation

For now, build it via go install.

Usage

lace - launch REPL

lace <filename> - execute a script. Lace uses .clj filename extension. For example: lace foo.clj. Normally exits after executing the script, unless --exit-to-repl is specified before --file <filename> in which case drops into the REPL after the script is (successfully) executed. (Note use of --file in this case, to ensure <filename> is not treated as a <socket> specification for the repl.)

lace - - execute a script on standard input (os.Stdin).

Project goals

Lace is designed to be a dynamic glue language for Go packages. It leans fully into Greenspun's 10th rule:

Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

In this case, we're picking Clojure rather than Common Lisp because it's the most commonly used lisp today.

The project began by forking Joker and beginning to add extensive reflection capabilities to allow clojure code to interact with Go types and code.

Differences with Clojure

1. Primitive types are different due to a different host language and desire to simplify things. Scripting doesn't normally require all the integer and float types, for example. Here is a list of Lace's primitive types:

Lace type	Corresponding Go type
BigFloat	big.Float
BigInt	big.Int
Boolean	bool
Char	rune
Double	float64
Int	int
Keyword	n/a
Nil	n/a
Ratio	big.Rat
Regex	regexp.Regexp
String	string
Symbol	n/a
Time	time.Time

Note that Nil is a type that has one value nil.

1. The set of persistent data structures is much smaller:

Lace type	Corresponding Clojure type
ArrayMap	PersistentArrayMap
MapSet	PersistentHashSet (or hypothetical PersistentArraySet, depending on which kind of underlying map is used)
HashMap	PersistentHashMap
List	PersistentList
Vector	PersistentVector

1. The following features are not implemented: protocols, records, structmaps, chunked seqs, transients, tagged literals, unchecked arithmetics, primitive arrays, custom data readers, transducers, validators and watch functions for vars and atoms, hierarchies, sorted maps and sets.
2. Unrelated to the features listed above, the following function from clojure.core namespace are not currently implemented but will probably be implemented in some form in the future: subseq, iterator-seq, reduced?, reduced, mix-collection-hash, definline, re-groups, hash-ordered-coll, enumeration-seq, compare-and-set!, rationalize, load-reader, find-keyword, comparator, resultset-seq, file-seq, sorted?, ensure-reduced, rsubseq, pr-on, seque, alter-var-root, hash-unordered-coll, re-matcher, unreduced.
3. Built-in namespaces have lace prefix. The core namespace is called lace.core. Other built-in namespaces include lace.string, lace.json, lace.os, lace.base64 etc. See standard library reference for details.
4. Miscellaneous:

• case is just a syntactic sugar on top of condp and doesn't require options to be constants. It scans all the options sequentially.
• slurp only takes one argument - a filename (string). No options are supported.
• ifn? is called callable?
• Map entry is represented as a two-element vector.
• resolving unbound var returns nil, not the value Unbound. You can still check if the var is bound with bound? function.

Coding Guidelines

• Dashes (-) in namespaces are not converted to underscores (_) by Lace, so (unlike with Clojure) there's no need to name .clj files accordingly.
• Avoid :refer :all and the use function, as that reduces the effectiveness of linting.

License

Copyright (c) Evan PHoenix. All rights reserved.
Copyright (c) Roman Bataev (from Joker). All rights reserved.
The use and distribution terms for this software are covered by the
Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
which can be found in the LICENSE file.

Lace contains parts of Clojure source code (from clojure.core namespace). Clojure is licensed as follows:

Copyright (c) Rich Hickey. All rights reserved.
The use and distribution terms for this software are covered by the
Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
which can be found in the file epl-v10.html at the root of this distribution.
By using this software in any fashion, you are agreeing to be bound by
the terms of this license.
You must not remove this notice, or any other, from this software.