Create scoping for variables

[Techcraft7]

Implementation

Create a stack like structure called Scope that has a Stack<Dictionary<string, object>>

When pushing a new scope, add all the contents of the current scope onto the stack so they are available

When popping a scope, set all of the values on the previous scope that exist on the scope to be popped to the value in the scope to be popped

Kind of C# for pushing/popping a scope:

public void PushScope() => stack.Push(stack.Peek());
public Dictionary<string, object> PopScope()
{
    var ret = stack.Pop();
    //get the previous scope
    var modified = stack.Pop();
    foreach (string key in modified.Keys)
    {
        if (!ret.ContainsKey(key))
        {
            continue;
        }
        modified[key] = ret[key];
    }
    //add the scope back to the stack
    stack.Push(modified);
    return ret;
}

Expressions to push scopes on start:

• loop
• if
• while
• function

[Techcraft7]

Done!
Code to verify that this works

write("Outside");
a = 5;
write(a);
if (true) {
	write("Inside");
	x = 3;
	write(a);
	write(x);
}
write("Outside");
write(x);

Should output:

Outside
5
Inside
5
3
Outside
CodingSeb.ExpressionEvaluator.ExpressionEvaluatorSyntaxErrorException: Variable [x] unknown in expression : [x]
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.EvaluateVarOrFunc(String expression, Stack`1 stack, Int32& i)
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.<>c__DisplayClass237_1.<Evaluate>b__0(ParsingMethodDelegate parsingMethod)
   at System.Linq.Enumerable.Any[TSource](IEnumerable`1 source, Func`2 predicate)
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.Evaluate(String expression)
   at System.Collections.Generic.List`1.ConvertAll[TOutput](Converter`2 converter)
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.EvaluateVarOrFunc(String expression, Stack`1 stack, Int32& i)
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.<>c__DisplayClass237_1.<Evaluate>b__0(ParsingMethodDelegate parsingMethod)
   at System.Linq.Enumerable.Any[TSource](IEnumerable`1 source, Func`2 predicate)
   at CodingSeb.ExpressionEvaluator.ExpressionEvaluator.Evaluate(String expression)
   at _7Sharp.Intrerpreter.Interpreter.Evaluate(String expr) in C:\Users\Techcraft7\Source\7Sharp\7Sharp\Intrerpreter\Interpreter.cs:line 456
System.InvalidOperationException: Stack empty.
   at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
   at System.Collections.Generic.Stack`1.Pop()
   at _7Sharp.Intrerpreter.Scope.PopScope() in C:\Users\Techcraft7\Source\7Sharp\7Sharp\Intrerpreter\Scope.cs:line 30
   at _7Sharp.Intrerpreter.Interpreter.InternalRun(String code, Object& returnValue, Boolean reset, KeyValuePair`2[] passedParams) in C:\Users\Techcraft7\Source\7Sharp\7Sharp\Intrerpreter\Interpreter.cs:line 343
   at _7Sharp.Intrerpreter.Interpreter.Run(String code) in C:\Users\Techcraft7\Source\7Sharp\7Sharp\Intrerpreter\Interpreter.cs:line 109