Plush Compiler

Author: Lishun Su fc56375

Introduction

PLush is new a programming language, designed to teach programming. It's goal is to be simple, and modular. The plush_testsuite contains the tests and the examples for the program.

Structure of the project

The project is structured by lexer, parser, type checker and code generator.

Lexer

The lexer uses the lex module from the PLY library. It receives the .pl file, tokenizes it, and passes the tokens to the parser. For more details, see src/tokens.py.

Parser

The parser uses the yacc module from the PLY library. It receives tokens from the lexer, transforms them into an Abstract Syntax Tree (AST), and passes the AST to the type checker. For more details, see src/parseRules.py.

Type Checker

The type checker walks through the AST to verify the correctness of element types, ensure functions have return statements, and perform liquid type checking. For more details, see src/semantic.py .

Code Generator

The code generator uses the llvmlite library. It receives the AST and generates LLVM code. For more details, see src/codegen/codegen.py.

Extra Feature

This project includes a Liquid Type Checker in the type checker. The data types supported for liquid type checking are boolean, integer and the float. You can use the Liquid Type Check like this:

function void main(){
    var a:int (a > 10):=11;
    var b : int (a > 10 && b < 10) := 9;
    
} 

After declaring the type, specify the condition inside parentheses.

Limitations

• This project has no operations for data type char and string if you want do something with those types better create c files and link with it.
• This project has a lot of optimization can be done, like in parser, code gen
• For liquid type check it cant check if the assign value is a paranmeter or an array(eg: var i : int (i > 0):= array[1])
• A function with return type differet void must have return at the end of the function returns inside of while or if is not counted
• Array cant define as global variable
• In a function, you cannot use an array as a parameter

How to excute

** Important : You may got this error -bash: ./plush.sh: /bin/bash^M: bad interpreter: No such file or directory when you excute the bash it is because when I am uploading the bash to git it sofers some changes by git LF will be replaced by CRLF the next time Git touches it (this change) ** How to solve

1. sudo apt-get install dos2unix(if you are using linux)

2. dos2unix plush.sh

3. Excute the command sh setup.sh (it will build the docker image and run a container)

4. Use the command sh plush.sh --tree examples/<filename>.pl, if you want to generate the .ll file and check the generated AST tree in the terminal or sh plush.sh examples/<filename>.pl, if you only want to generate the .ll file.

5. Excute the command sh excute_plush.sh, if you want to get the excutable of the file .ll