Mini Lisp

Introduction

This 400+ lines lisp interpreter heavily utilizes STL and C++/17 trait to implement. You can access the original Python implementation here. Aside from pure C++ implementation, the tokenize and parser implemented by Lex and Bison(yacc) is included in this branch.

The Spec file, Grammar

No.	Name	Description	Complete
1.	Syntax Validation	Print “syntax error” when parsing invalid syntax	✅
2.	Print	Implement print-num statement	✅
3.	Numerical Operations	Implement all numerical operations	✅
4.	Logical Operations	Implement all logical operations	✅
5.	if Expression	Implement if expression	✅
6.	Variable Definition	Able to define a variable	✅
7.	Function	Able to declare and call an anonymous function	✅
8.	Named Function	Able to declare and call a named function	✅
9.	Recursion	Support recursive function call	✅
10.	Type Checking	Print error messages for type errors	✅
11.	Nested Function	Nested function (static scope)	✅
12.	First-class Function	Able to pass functions, support closure	✅

Getting Start

make && ./mini_lisp -r

Testing Environment

• OS: macOS 11.5.2 (Darwin Kernel Version 20.6.0)
• Device: MacBookPro14,1
• Compiler: clang 13.0.0
• Compile flags: -Wno-register -O0 -g -Wall -std=c++20

Problems Encountered

What is the best way of preventing memory leaks in a yacc-based parser?

• https://stackoverflow.com/questions/40227135/why-yacc-have-memory-leak-at-exit

Are GCC and Clang parsers really handwritten?

• https://stackoverflow.com/questions/6319086/are-gcc-and-clang-parsers-really-handwritten

C++ using declaration recursive

• https://vittorioromeo.info/index/blog/variants_lambdas_part_2.html

variant

• https://zhuanlan.zhihu.com/p/366537214
• https://kheresy.wordpress.com/2017/10/16/cpp17-variant/

Bison variant

• https://stackoverflow.com/questions/50776052/flex-bison-cannot-use-semantic-type