Berry

Introduction

Berry is a ultra-lightweight dynamically typed embedded scripting language. Berry's design goals include running on very small memory devices, and so, Berry must be very streamlined. Its core language only supports a few types, but we still provide class and closure support.

The implementation of Berry include a one pass compiler and register-based VM, all the codes are written in ANSI C. Berry is not everything is object. Some simple value types, such as int, real, boolean and string are not class object, but list, map and range are class object. This is a consideration about performance. Register-based VM is also based on this consideration.

Documents

https://gztss.github.io/berry

Features

Base Type
- Numerical value: Integer (int) and Real (real)
- Boolean: true and false
- String: Single quotation-mark string and double quotation-mark string
- List: Continuous memory list, like [1, 2, 3]
- Map: Hash Map, like { 'a': 1, 2: 3, 'map': {} }
- Range: include a lower and a upper integer value, like 0..5
Operator and Expression
- Assign operator: =
- Relational operator: <, <=, ==, !=, >, >=
- Logic operator: &&, ||, !
- Arithmetic operator: +, -, *, /, %
- Field operator: .
- Index operator: []
- Connect string operator: +
- Brackets: ()
Control Structure
- Conditional statement: if-else
- Iteration statement: while and for
- Jump statement: break
Function
- Local variable and block scope
- Return statement
- Nested functions definition
- Closure based on Upvalue
Class
- Inheritance (only public single inheritance)
- Method and Operator Overload
- Constructor method
Module Management
- Statically allocated memory: no RAM used before import.
- Module nesting.

Build

install the readline library (Linux or MacOS)

sudo apt install libreadline-dev # Ubuntu
brew install readline            # MacOS

Build:

make

Run:

./berry # Bash
berry   # Windows CMD

Editor pulgins

Visual Studio Code pulgin are in this directory: ./tools/pulgins/vscode.

Examples

After compiling successfully, use the berry command with no parameters to enter the REPL environment:

Berry 0.0.1 (build in Dec 24 2018, 18:12:49)
[GCC 8.2.0] on Linux (default)
>

Now enter this code:

print("Hello world!")

You will see this output:

Hello world!

You can copy this code to the REPL:

def list_iter(list)
    index = 0
    def it()
        value = list[index]
        index = index + 1
        return value
    end
    return it
end
l = [0, 1, 2, 3, 4, 5]
lout = []
it = list_iter(l)
v = it()
while (v != nil)
    lout.append(v)
    v = it()
end
print(lout)

This examples is a simple list iterator. Let's look at the output:

[0, 1, 2, 3, 4, 5]

You can save the above code to a file (eg test.be) and run:

./berry test.be

This will also get the correct output.