Giter Club home page Giter Club logo

generalbasic-lang's Introduction

GeneralBasic

A stack-based systems language that supports structures, functions, expressions, and user-defined operator behaviour. Currently compiles to URCL with plans to add additional formats in the future.

Why Python?

The initial implementation of this compiler is written in Python. This allowed for flexibility during development and guaranteed portability across major platforms. This compiler may be ported to other languages in the future should the need arise.

Invoking the Compiler

python gb.py -o MyProgram.urcl MyProgram.gb
Argument Description
gb.py This is the main compiler script.
-o This is the output flag, which indicates the argument that should be used for the name of the output file.
MyProgram.urcl The name of the output file.
MyProgram.gb The name of an input source file. Multiple source files can be included.

GeneralBasic Syntax

Structures

Structures are a data type that can store multiple pieces of information, called fields.

Structure Ball
	Dim X As Integer
	Dim Y As Integer
End Structure

Pointers

Pointers are declared by adding an asterisk (*) to the end of the referenced type name.

Dim ballAddress As Ball*

A pointer can be dereferenced by using the ValueOf operator.

Dim ballAddress As Ball*

...

Dim ball As Ball
ball = ValueOf(ballAddress)

A pointer to a variable can be obtained using the AddressOf operator.

Dim ball As Ball

...

Dim ballAddress As Ball*
ballAddress = AddressOf(ball)

Type Casting

Type casting can be performed with the As operator.

Dim ballAddress As Ball*
ballAddress = 0x100 As Ball*

Functions and Subroutines

Functions can be declared with pass-by-value parameters and a return value.

Function AddNumbers(a As Integer, b As Integer) As Integer
	Return a + b
End Function

If a return value is not required, a subroutine can be used instead.

Sub PrintNumbers(a As Integer, b As Integer)
	Print(a)
	Print(b)
End Sub

Parameters can be made to pass-by-reference by adding ByRef before the parameter name.

Sub Bounce(ByRef this As Ball)
	this.Y = this.Y * -1
End Sub

Inline Assembly

Inline assembly allows for custom operations not supported by the compiler to be implemented on the target platform. Each command is prefixed with the Asm keyword followed by one of three command names: Load, Save, or Exec.

Load accepts one variable as an argument and pushes it onto the local stack.

Save accepts one variable as an argument and pops a value from the local stack into it.

Exec accepts one or more arguments and emits them as a raw instruction.

Sub AddOne(ByRef value As Integer)
	Asm Load value
	Asm Exec pop R1
	Asm Exec inc R1 R1
	Asm Exec psh R1
	Asm Save value
End Sub

Inline assembly statements are not exempt from emitter-level optimization and may be simplified or modified in cases such as extraneous stack operations or unused registers. Care should be taken to not modify the program's base pointer, as doing so could lead to unexpected or unsafe behaviour.

generalbasic-lang's People

Contributors

lucidadragon avatar

Recommend Projects

  • React photo React

    A declarative, efficient, and flexible JavaScript library for building user interfaces.

  • Vue.js photo Vue.js

    ๐Ÿ–– Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.

  • Typescript photo Typescript

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

  • TensorFlow photo TensorFlow

    An Open Source Machine Learning Framework for Everyone

  • Django photo Django

    The Web framework for perfectionists with deadlines.

  • D3 photo D3

    Bring data to life with SVG, Canvas and HTML. ๐Ÿ“Š๐Ÿ“ˆ๐ŸŽ‰

Recommend Topics

  • javascript

    JavaScript (JS) is a lightweight interpreted programming language with first-class functions.

  • web

    Some thing interesting about web. New door for the world.

  • server

    A server is a program made to process requests and deliver data to clients.

  • Machine learning

    Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.

  • Game

    Some thing interesting about game, make everyone happy.

Recommend Org

  • Facebook photo Facebook

    We are working to build community through open source technology. NB: members must have two-factor auth.

  • Microsoft photo Microsoft

    Open source projects and samples from Microsoft.

  • Google photo Google

    Google โค๏ธ Open Source for everyone.

  • D3 photo D3

    Data-Driven Documents codes.