Welcome to berry’s documentation!

Berry is a ultra-lightweight dynamically typed embedded scripting language. It is designed for lower-performance embedded devices. The Berry interpreter-core’s code size is less than 40KiB and can run on less than 4KiB heap (on ARM Cortex M4 CPU, Thumb ISA and ARMCC compiler).

The interpreter of Berry include a one-pass compiler and register-based VM, all the code is written in ANSI C99. In Berry not every type is a class 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 the same meaning as above.

Berry has the following advantages:

  • Lightweight: A well-optimized interpreter with very little resources. Ideal for use in microprocessors.

  • Fast: optimized one-pass bytecode compiler and register-based virtual machine.

  • Powerful: supports imperative programming, object-oriented programming, functional programming.

  • Flexible: Berry is a dynamic type script, and it’s intended for embedding in applications. It can provide good dynamic scalability for the host system.

  • Simple: simple and natural syntax, support garbage collection, and easy to use FFI (foreign function interface).

  • RAM saving: With compile-time object construction, most of the constant objects are stored in read-only code data segments, so the RAM usage of the interpreter is very low when it starts.

Features

Base Type

  • Nil: nil

  • Boolean: true and false

  • Numerical: Integer (int) and Real (real)

  • String: Single quotation-mark string and double quotation-mark string

  • Class: Instance template, read only

  • Instance: Object constructed by class

  • Module: Read-write key-value pair table

  • List: Ordered container, like [1, 2, 3]

  • Map: Hash Map container, 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: +, -, *, /, %

  • Bitwise operator: &, |, ~, ^, <<, >>

  • Field operator: .

  • Subscript operator: []

  • Connect string operator: +

  • Conditional operator: ? :

  • Brackets: ()

Control Structure

  • Conditional statement: if-else

  • Iteration statement: while and for

  • Jump statement: break and continue

Function

  • Local variable and block scope

  • Return statement

  • Nested functions definition

  • Closure based on Upvalue

  • Anonymous function

  • Lambda expression

Class

  • Inheritance (only public single inheritance)

  • Method and Operator Overload

  • Constructor method

  • Destructive method

Module Management

  • Built-in module that takes almost no RAM

  • Extension module support: script module, bytecode file module and shared library (like *.so, *.dll) module

GC (Garbage collection)

  • Mark-Sweep GC

Exceptional Handling

  • Throw any exception value using the raise statement

  • Multiple catch mode

Bytecode file support

  • Export function to bytecode file

  • Load the bytecode file and execute