basic-interpreter-in-go

Table of Contents

1. How to install and run the code
2. Conversion from Python to Go
3. Added features from the Python version
4. Language Features

Install and How To Run

Install go

go to https://go.dev/doc/install to get the instructions on how to install go

Run the code

With No Arguments

• no arguments runs the RELP
  • The RELP can be exited by typing exit

go run .

With Arguments

• you can also give it a file to run instead

go run . test.bean

Build the code

go build ./...

Run the Test Code

go test ./...

Conversion from Python

Strongly typed

Go is a strongly typed language so it required that each function have a return type and all variables also be assigned a type Go does have the interface type, which accepts any type, but requires a binding when it needs to be a specific type I also had to create a structure called Token to handle the tokens because arrays must be all the same value in go

Error Handling

Go does not have the same ability to catch errors as python. Instead it uses a testing library to return error values within the parser and tokenizer. Every function returns an error value. It can either be nil or an error. These error messages are passed up the stack until the Evaluate function returns it

Added Features From the Python Version

Print Function

The print function can take multiple values separated by a comma. It delimiter can also be changed with the end= variable

print("The value of 1+2 is: ", 1+2, end = ""); print("");

Output>>The value of 1+2 is: 3

Do While Loops

do whiles are also possible within this implementation of the interpreter.

x = 10;
print("The value of x is: ", end = "");
do{
    print(x, end=" ");
    x = x-1;
}while(x > 0);
print("");

Output>>The value of x is: 10 9 8 7 6 5 4 3 2 1 

String Comparison

Strings can also be compared within the expressions You can use <, <=, >, >=, !=, and ==

x = "hello";
y = "Hello";
print(x == y);

char = "a";
if (char < "b"){
    print("a is less than b");
}
else{
    print("a is greater than b");
}

Output>>false
      >>a is less than b

Language Features

Print Values

print statements must be wrapped in () and can print multiple values separated by a comma. Each print statements ends in a newline by default

print (5);
print("hello");
print (1 < 3);
print ("a" < "b");
print("hello", "world");
print("The value of 1+2 is: ", 1+2);

You can change the delimiter by adding an end= argument to the print function

print("The value of 1+2 is: ", 1+2, end = ""); print("");

Output>>The value of 1+2 is: 3

Variables

You can store numbers and strings. The numbers can be integers or floating points

x = 12;
y = "hello world";
z = 1.34;

True values are considered numbers with a value greater than 1

x = 1; // true
x = 0; // false
x = 3; //true

If Statement

if statements condition must have () and the body must have {}

if (1 < 3){
    print 1;
}

else statements also exist

if (1 < 3){
    print 1;
}
else {
    print 3;
}

since number greater than 1 are true, you can use numbers as the condition

if (5){
    print 5;
}

While Statements

while loops are also allowed. The condition must be in () and be followed by {}

i = 10;
while (i > 0){
    print i;
    i = i - 1;
}

This can be done easier with just using a number

x = 10;
while(x){
    print x;
    x = x - 1;
}

Do While Statements

do while loops are also allowed. Conditions must be within () and the body must be contained by {}

i = 10;
do{
    print i;
    i = i - 1;
} while(i > 0);