Statement

Let’s move forward to the minimum statement support, The Stmt is defined as an abstract class to hold Expr, with derived PrintStmt and ExprStmt. The PrintStmt would print the value to communicate with the external world.

The statement parsing is pretty much the same:

std::unique_ptr<Stmt> Parser::statement() {
  if (match({TOKEN_PRINT}))
    return print_stmt();
  return expr_stmt();
}

We also extract the tokenize from parse, so we could keep the unit tests on parsing expressions. The logic of the parse is quite straightforward:

void Parser::parse() {
  while (!ends()) {
    program.push_back(statement());
  }
}

In the PR #7, we are able to parse the statements. In the next chapter, we will integrate the LLVM backend for code generation.