T
TypeDB•21h ago
rajivranganath

Understanding behavior of recursive functions

I am trying to see if I can get a better understanding of this example 
fun transitive_places($place: place) -> { place }:
  match
    {
      locating (located: $place, location: $parent);
    } or {
      locating (located: $place, location: $middle);
      let $parent in transitive_places($middle);
    };
  return { $parent };
fun transitive_places($place: place) -> { place }:
  match
    {
      locating (located: $place, location: $parent);
    } or {
      locating (located: $place, location: $middle);
      let $parent in transitive_places($middle);
    };
  return { $parent };
In the statement let $parent in transitive_places($middle);, is the variable $parent scoped only to its branch of the disjunction or the entire disjunction?
1 Reply
krishnan
krishnan•21h ago
Entire disjunction. I've tried to explain the variable naming rules here: https://typedb.com/docs/core-concepts/typeql/query-variables-patterns#_disjunctions The tl;dr is variable names are scoped to the pipeline - in this case the whole body of the function. (Select, delete, and (I think) reduce stages free up variable names to be re-used in subsequent stages)

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