Named Custom For Expansion

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There can be multiple ways to iterate a data structure that do not fit into the narrow descriptions of the basic For_Flags enums such as reverse iteration or by pointer. For example, someone might want to make a Tree struct with a breath-first search and a depth-first search iteration of a Tree. This can be accomplished by writing a breath first search macro and a depth first search macro with the following parameter arguments:

macro :: (o: *Object, body: Code, flag: For_Flags) #expand;

Writing a macro with that function signature allows the macro to be used to label a for loop expansion. In the following example below, we create a bfs and dfs for expansion macro that allows the for loop to traverse either in breath first search or depth first search respectively.

tree: Tree;
for :bfs node: tree {
  // breath first search the tree
  print("%\n", node);
}

for :dfs node: tree {
  // depth first search the tree
  print("%\n", node);
}


Tree :: struct {
  data: int;
  left: *Tree;
  right: *Tree;
}

bfs :: (t: *Tree, body: Code, flags: For_Flags) #expand {
  // define breath first search here..
}

dfs :: (t: *Tree, body: Code, flags: For_Flags) #expand {
  // define depth first search here..
}