ExDatalog.Validator.Error (ExDatalog v0.2.0)

Structured validation error types for ExDatalog programs.

Every error is a %ExDatalog.Validator.Error{} struct with:

kind — a machine-readable atom identifying the error category.
context — a map with error-specific context (relation, variable, rule index, etc.).
message — a human-readable description.

Error Kinds

Kind	Phase	Description
`:arity_mismatch`	1	Fact or atom term count differs from relation arity
`:undefined_relation`	1	Reference to a relation not declared in the program
`:invalid_term`	1	A term is not a valid `ExDatalog.Term.t()`
`:duplicate_relation`	1	A relation is declared more than once
`:unsafe_variable`	2	A head variable does not appear in any positive body atom
`:range_restriction`	2	A variable in a constraint is not bound by positive body atoms
`:unstratified_negation`	2	A negative edge appears in a dependency cycle
`:unbound_constraint_variable`	2	A constraint references a variable not yet bound
`:invalid_body_literal`	1	A body literal is not `{:positive, atom}` or `{:negative, atom}`

Examples

iex> ExDatalog.Validator.Error.new(:undefined_relation, %{relation: "parent", rule_index: 0}, "rule 0 references undefined relation \"parent\"")
%ExDatalog.Validator.Error{
  kind: :undefined_relation,
  context: %{relation: "parent", rule_index: 0},
  message: "rule 0 references undefined relation \"parent\""
}

Summary

Types

kind()

t()

Functions

new(kind, context, message)

Constructs a new validation error.

Types

kind()

@type kind() ::
  :arity_mismatch
  | :undefined_relation
  | :invalid_term
  | :duplicate_relation
  | :unsafe_variable
  | :range_restriction
  | :unstratified_negation
  | :unbound_constraint_variable
  | :invalid_body_literal
  | :wildcard_in_head

t()

@type t() :: %ExDatalog.Validator.Error{
  context: map(),
  kind: kind(),
  message: String.t()
}

Functions

new(kind, context, message)

@spec new(kind(), map(), String.t()) :: t()

Constructs a new validation error.

Examples

iex> ExDatalog.Validator.Error.new(:arity_mismatch, %{relation: "parent", expected: 2, got: 1}, "arity mismatch")
%ExDatalog.Validator.Error{
  kind: :arity_mismatch,
  context: %{relation: "parent", expected: 2, got: 1},
  message: "arity mismatch"
}