bravo/dbag

This module provides functions to work with DBags

Types

DBag

opaque </>

A duplicate bag etc. Keys may occur multiple times per table, and verbatim copies of an object can be stored.

pub opaque type DBag

Functions

delete

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pub fn delete(dbag: DBag) -> Bool

Deletes a DBag.

Table lifetime is static, and memory is only freed when the owner process is killed! Don’t forget to call this function!

insert

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pub fn insert(dbag: DBag, objects: List(a)) -> Bool

Inserts a list of tuples into a DBag.

Returns a Bool representing if the inserting succeeded.

If True, all objects in the list were inserted.
If False, none of the objects in the list were inserted. This may occur if the size of the tuple is less than the DBag’s size.

If an Object with the same key already exists, then the old Object will be overwritten with the new one.

insert_obj

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pub fn insert_obj(dbag: DBag, objects: List(Object(a))) -> Bool

Inserts a list of Objects into a DBag. It is recommended to use insert instead when possible, as this uses that function under the hood.

Returns a Bool representing if the inserting succeeded.

If True, all objects in the list were inserted.
If False, none of the objects in the list were inserted. This may occur if the size of the tuple is less than the DBag’s size.

If an Object with the same key already exists, then the old Object will be overwritten with the new one.

lookup

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pub fn lookup(dbag: DBag, key: a) -> List(Object(Dynamic))

Gets an Object from a DBag.

Returns an Option containing the object, if it exists.

If Some, then the object was found. ETS tables do not store types, so you must decode a Dynamic inside the Object.
If None, then the DBag did not contain any Object with the specified key.

new

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pub fn new(
  name: String,
  keypos: Int,
  access: Access,
) -> Result(DBag, Option(ErlangError))

Creates a new ETS table configured as a duplicate bag: keys may occur multiple times per table, and verbatim copies of an object can be stored.

name: An atom representing the name of the DBag. There may only be one ETS table associated with an atom. keypos: The index (1-indexed) that represents the key position of the object. This function fails if this is less than 1. access: Determines how visible the table is to other processes.

Public: Any process can read or write to the DBag.
Protected: Any process can read the DBag. Only the owner process can write to it.
Private: Only the parent process can read or write to the DBag.

Returns a result of the created DBag, which can be used by other functions in this module. If this function errors with None, then you likely put in an illegal keypos value. Otherwise, something went wrong in the FFI layer and an error occured in Erlang land.