Add support for switch-case in mani

[ankitshubham97]

---

name: Switch-case about: I have added the feature of switch-case to the language.

Is your PR related to a feature request or Bug report? If applicable, please list feature request number or bug report ID.

It is related to an improvement feature #79.

Describe your PR A clear and concise description of what your pull request is changing or adding.

It is adding the feature of switch statements.

Describe intended use A clear and concise description of the intended use of the feature. Along with example code.

From #79: The addition of switch statements would make this language just that little bit better. It would remove the need for mass amounts of if statements. Sample code:

let a = 1;
switch (a) {
case 1 :
say "a";
case 2 :
say "b";
case 3 :
say "c";
}

How did you fix the bug? If applicable, how did you fix the bug? Please use code snippets too.

N/A

Is it in the form of a library

• No

If applicable what is the library called?

N/A

Does your PR replace an existing system If applicable, please describe how this PR changes the use of a related item.

No.

Additional comments Limitations:

• Does not support "default" keyword for now, added a TODO.
• Does not support multiple statements within a case, only one statement per case works for now. So, something like following does not work:

  switch (a) {
  case 1 :
  say "1";
  say "2";
  }

[crazywolf132]

Great work. I am just going to hold off merging until it supports more than one line per case.

I will add a WIP tag to the title.

[ankitshubham97]

@crazywolf132 Commit 1625e28 now takes care of supporting more than one line per case.

[ankitshubham97]

@crazywolf132 I have a query. In src/com/mani/lang/core/Interpreter.java,:

  @Override
  public Void visitBreakStmt(Stmt.Break stmt) {
    throw new Return();
  }

Why are we throwing a RuntimeException for 'break' statements? Is it because it is still unimplemented?

[crazywolf132]

@ankitshubham97 That was just how i chose to take care of break statements. If you believe there is a better way, by all means. Feel free to change it.

If you think this is good to go, please create a test case for it. Then we can merge.

[crazywolf132]

@Kalekdan Anything to add?

[ankitshubham97]

@crazywolf132 Added test in c098248.

[crazywolf132]

Great work

[ankitshubham97]

Thanks! #79 can be closed now.