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
<>
```

```
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.

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
$ JANET_PATH=janet_modules/ jpm load-lockfile
$ JANET_PATH=janet_modules/ jpm build
$ cp build/ec <somewhere on your path>
```