OSCLAN

Compiler for OSCLAN (Old-SChool LANguage), a business-oriented toy language that compiles to AArch64 Assembly.

Context

I have been wanting to build a compiler for some time, however the main challenge has been the code generation part. The original plan was to build a compiler for Apple Silicon chips, however it might turn out that it would be easier to target something like MSIL first.

If you have any thoughts, feel free to share them by opening up a pull request or an issue. My main focus at this point is on getting things working, so the code will definitely not be as clean as it should be. There is no real plan involved here; I'm just making everything up as I go along.

Usage

1. Open a terminal
2. $ ./build.sh
3. ./osclanc -i simple.osc to compile Examples/simple.osc (the directory is currently hardcoded)

Language specifications

Types

Name	Size	Description
string(n)	n bytes	Field containing ASCII characters.
int(n)	n bytes	Signed integer value.
uint(n)	n bytes	Unsigned integer value.
struct	-	Implicit struct, only allowed in certain contexts.

A struct can be turned into an array by appending (n), where n denotes the number of occurrences, e.g., struct(10) for a list of ten items. Build-in type names are case-insensitive, hence string is equivalent to STRING.

Keywords

The language has the following (case-insensitive) keywords:

Keyword	Description
declare	Used for declaring variables, structures procedures.
public	Modifier used to make a procedure/struct visible outside the current file.
private	Modifier used to make a procedure/struct invisible outside the current file.
struct	Denotes a data structure.
begin	Start of a block.
end	End of a block.
init	Initializes a struct/type, e.g., init string(10) to initialize a string of 10 characters.
anon	Used in combination with declare, used when initializing an implicit struct.
ret	Returns from the procedure.
print	Prints the arguments to stdout.
if	Denotes a block of code that is only executed when the expression holds true.
else	Denotes a block of code that is only executed if the preceding if statement is not executed.
then	Start of the block of code that is executed in an if-else construction.
space	Shorthand that denotes an arbitrary number of spaces.
zero	Shorthand that denotes an arbitrary number of zeros.
ok	Alias of zero, only used in combination with ret.
for	While-loop.
increment	Increments a scalar value by 1
decrement	Decrements a scalar value by 1

Directives

Directive	Possible values	Description
import	any string	Imports a module.
mangler	enable, disable	Enables/disables the identifier mangler.
module	any string	Sets the name of the current module.

Todo

• Code generation (AArch64 assembly)
• Finish parser
  • Increment/decrement
  • Expressions
  • If-else statements
  • Loops
• Clean up pointer mess in parser
• Refactoring
• Semantic analyzer
• Optimizer
• Imports and modules
• Statistics (e.g., number of tokens per token type)
• Syntax highlighting in VS Code
• Unit tests (once tokenizer and parser are done)
• Assembly code blocks

Note: optimizer and more advanced analyzer will be added after a basic code generator.

Technical Documentation

To build the docs, ensure that you have docfx installed. Then, in a terminal, run the build-docs.sh script. In order to view the docs, open the Docs/_site/index.html file in a web browser.