Class: LD::Patch::Algebra::Cut

Inherits:
SPARQL::Algebra::Operator::Unary show all
Includes:
SPARQL::Algebra::Evaluatable, SPARQL::Algebra::Update
Defined in:
vendor/bundler/ruby/3.0.0/bundler/gems/ld-patch-1e120ae2cd50/lib/ld/patch/algebra/cut.rb

Overview

The LD Patch cut operator.

The Cut operation is recursively remove triples from some starting node.

Examples:

(cut ?a)

Constant Summary collapse

NAME =
:cut

Constants inherited from SPARQL::Algebra::Operator::Unary

SPARQL::Algebra::Operator::Unary::ARITY

Constants inherited from SPARQL::Algebra::Operator

SPARQL::Algebra::Operator::ARITY, SPARQL::Algebra::Operator::IsURI, SPARQL::Algebra::Operator::URI

Instance Attribute Summary

Attributes inherited from SPARQL::Algebra::Operator

#operands

Instance Method Summary collapse

Methods included from SPARQL::Algebra::Evaluatable

#apply, #evaluate, #memoize, #replace_aggregate!, #replace_vars!

Methods included from SPARQL::Algebra::Update

#graph_name=, #unshift, #variables

Methods inherited from SPARQL::Algebra::Operator::Unary

#initialize

Methods inherited from SPARQL::Algebra::Operator

#aggregate?, arity, base_uri, #base_uri, base_uri=, #bind, #boolean, #constant?, #deep_dup, #each_descendant, #eql?, #evaluatable?, evaluate, #executable?, #first_ancestor, for, #formulae, #initialize, #inspect, #ndvars, #node?, #operand, #optimize, #optimize!, #parent, #parent=, #prefixes, prefixes, prefixes=, #rewrite, #to_binary, #to_sxp, #to_sxp_bin, #validate!, #variable?, #vars

Methods included from SPARQL::Algebra::Expression

cast, #constant?, #evaluate, extension, extensions, for, #invalid?, new, #node?, open, #optimize, #optimize!, parse, register_extension, #to_sxp_bin, #valid?, #validate!, #variable?

Constructor Details

This class inherits a constructor from SPARQL::Algebra::Operator::Unary

Instance Method Details

#execute(queryable, options = {}) ⇒ RDF::Query::Solutions

Executes this upate on the given writable graph or repository.

Parameters:

Returns:

  • (RDF::Query::Solutions)

    A single solution including passed bindings with var bound to the solution.

Raises:

  • (IOError)

    If no triples are identified, or the operand is an unbound variable or the operand is an unbound variable.

See Also:



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# File 'vendor/bundler/ruby/3.0.0/bundler/gems/ld-patch-1e120ae2cd50/lib/ld/patch/algebra/cut.rb', line 28

def execute(queryable, options = {})
  debug(options) {"Cut"}
  bindings = options.fetch(:bindings)
  solution = bindings.first
  var = operand(0)

  # Bind variable
  raise LD::Patch::Error.new("Operand uses unbound variable #{var.inspect}", code: 400) unless solution.bound?(var)
  var = solution[var]

  cut_count = 0
  # Get triples to delete using consice bounded description
  queryable.concise_bounded_description(var) do |statement|
    queryable.delete(statement)
    cut_count += 1
  end

  # Also delete triples having var in the object position
  queryable.query({object: var}).each do |statement|
    queryable.delete(statement)
    cut_count += 1
  end

  raise LD::Patch::Error, "Cut removed no triples" unless cut_count > 0

  bindings
end