Writing An Interpreter In Go🐒

Monkey is a programming language that I wrote based on book Writing An Interpreter In Go

Thx for him for providing the amazing book！！

Overview

Monkey supports six different primitive types, Integer, Boolean, Array, String, Functions and Map.

It can do mathematical calculations, variable bindings, functions and the application of those functions, conditionals, return statements and even advanced concepts like higher-order functions and closures.

I also add five builtin functions.

1. len()
Input Type: Supports String and array
Return Type: int
Usage: Return the length of the String or array
eg: let a = "123";
		len(3)	//  Print 3

2. first
Input Type:	Array
Return Type: All Types
Usage:	Return the first element of the array
eg:	let a = [1, 2, 3]
		first(a)	// Print 1
		
3. last
Input Type:	Array
Return Type: All Types
Usage:	Return the last element of the array
eg:	let a = [1, 2, 3]
		first(a)	// Print 3
		
4. rest
Input Type: Array
Return type: All Types
Usage: Return the array with its first element removed
eg:	let a = [1, 2, 3]
		rest(a)  // Print [2, 3], Notify that it will not modify the original array
		a				 // Print [1, 2, 3]
    
5. puts
Input Type: All Type
Return type: None
Usage: Print All elements in the array
eg:	let a = [1, 2, 3]
		puts(a)  // Print [1, 2, 3]

Error handling

When the input type is wrong, the repl will print clear error Message.

Hello isabella! This is the Monkey Programming Language!
Feel free to type in commands
>>let a = 1;
>>a[1];
ERROR: index operator not supported: INTEGER

When it comes parser Error, a Monkey face will be printed.

Hello isabella! This is the Monkey Programming Language!
Feel free to type in commands
>>a[123
            __,__
   .--.  .-"     "-.  .--.
  / .. \/  .-. .-.  \/ .. \
 | |  '|  /   Y   \  |'  | |
 | \   \  \ 0 | 0 /  /   / |
  \ '- ,\.-"""""""-./, -' /
   ''-' /_   ^ ^   _\ '-''
       |  \._   _./  |
       \   \ '~' /   /
        '._ '-=-' _.'
           '-----'
Woops! We ran into some monkey business here!
 parser errors:
        expected next token to be ], got EOF instead

Environment

Golang (Tested on: go1.13.4 darwin/amd64)

Running the console

go run main.go

Tests