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atomic_list_concat/2

Module​

Built-in predicate.

Description​

Unifies Atom with the concatenation of the atomic textual representation of each element in List.

where:

  • List is a proper list of ground terms. Each element is converted using term_to_atom/2, so atoms, numbers, double-quoted strings, lists and compounds are supported;
  • Atom is an atom representing the concatenation of the textual representation of each element in List.

Throws:

  • error(instantiation_error, atomic_list_concat/2) when List is insufficiently instantiated;
  • error(type_error(list, List), atomic_list_concat/2) when List is not a proper list.

Signature​

atomic_list_concat(+List, ?Atom) is det

Examples​

Concatenate atomic values into a single atom​

This scenario demonstrates how atomic_list_concat/2 concatenates the textual representation of several atomic values.

Here are the steps of the scenario:

  • Given the program:
  • Given the query:
atomic_list_concat([hello, '-', 42, '-', world], Atom).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 6660
answer:
  has_more: false
  variables: ["Atom"]
  results:
  - substitutions:
    - variable: Atom
      expression: "'hello-42-world'"