## ~subsetpark/ec

ref: e85c9853e2f2332e47aaa381a543d0f78de5cd4e ec/README.md -rw-r--r-- 2.0 KiB
e85c9853 — Zach Smith test-arity helper 10 months ago

An RPN calculator with array operations and quotations.

``````<> \$ 4 5 +
<9> \$ p
9
<> \$ [3 4 5] 6 x
<[18 24 30]> \$ 0 swap
<[18 24 30]> \$ (+) /
<72> \$ p
72
<>
``````

## #Usage

``````   ec <expression>: evaluate <expression> as a sequence of
ec commands and print the resulting stack.
ec             : enter interactive (repl) mode.
``````

ec operates as a RPN desk calculator with quotation and vector math functions. Ordinarily, tokens are evaluated from left to right as they're pushed onto the stack. eg.,

``````   3 4 +
``````

will push 3, then 4, then apply the operation +, which will pop two elements from the stack, add them, and push their sum.

To quote a sequence of tokens, wrap it in parentheses. eg.,

``````   (3 4 +)
``````

will push a single quotation containing just those three tokens, which can be applied by subsequent commands.

To create a vector, enclose a sequence of numbers or other vectors in square brackets. eg.,

``````   [3 4]
``````

will create a 1-dimensional vector and push it on the stack.

Vectors can be added to other vectors or individual numbers. eg.,

``````   [3 4] 2 +
``````

will add 2 to each element of [3 4], resulting in [5 6].

``````   [3 4] [2 1] +
``````

will add matching elements of vectors, resulting in [5 5].

Vectors can be of arbitrary dimension, but must contain homogeneous data. eg.,

``````   [[2 1] [0 0]]
``````

is a valid vector (of shape [2 2]), but

``````   [[2] [0 0]]
``````

is not.

For a full dictionary listing, enter the special command:

``````   ??
``````

To get a description of any word, quote it and use the special command. eg.,

``````   (!) ?
``````

Will print a description of the `apply` adverb.

## #Installation

On Arch Linux, install `ec` via AUR:

`yay -S ec`

On other systems, install the Janet language, clone this repository and build using `jpm`:

``````\$ mkdir janet_modules