Niko can be started in several modes: repl, test or eval.
If you run niko -h then you will see help with quick overview:
niko ecc731b Release (2024-05-25T18:35:35Z) http://github.com/mikea/niko
USAGE:
bin/niko [FLAGS] [OPTIONS]
FLAGS:
-z Do not load the prelude
-v Verbose test execution
-h Print help information
OPTIONS:
-e <expr> Evaluate niko expression
-t <test.md> Run markdown test
Enters the repl if no options are specified (using rlwrap is recommended).
Niko tests are ordinary markdown files. To execute the test run niko -t <test_file.md>.
Inside the file system looks for markdown code markers ```nk and ```nkt.
The code withing nk block is evaluated as is.
The output (if any) will be sent to stdout.
The code within nkt block has the input-and-response structure,
where interpreter input is on lines starting with > (like repl), and everything else is the output. The system checks the output against the expected one and fails if there's any mismatch.
test.md:
# Simple Test
This `nk` block will be executed verbatim:
```nk
: add_2 2 + ;
```
This `nkt` block has input/response structure
and looks like repl:
```nkt
> 1 add_2 .
3
```
See example_test.md for more deliberate test example. s
Niko program consists of a sequence of words separated by whitespaces.
Whitepsaces consist of space, tab and new line character.
Words are evaluated left to right.
Comments are encolsed by (): ( this is niko comment ).
Array is the only value in the language. Everything is represented as an array.
Following element types are supported:
- char
- i64
- f64
Characters are 8-bit. Arrays of characters are called strings and are entered using quotes:
> "abc" .
"abc"
Integers are signed, 64-bit wide and do not contain dot symbol:
> 0 1024 -42 . . .
-42
1024
0
Floats are 64-bit wide. Float literal must contain . or e symbols:
0., 1e-16, -3.1415.
To create an array literal use [ ] words to enter them (remember the spaces):
> [ 1 2 3 ] .
[ 1 2 3 ]
> [ [ 1. 2. 3. ] [ 4. 5. 6. ] ] .
[ [ 1. 2. 3. ] [ 4. 5. 6. ] ]