Function constantFoldOperator

constantFoldOperator(
    c: TransformationContext,
    operator: string,
    args: Expression[],
    boundVariables?: ReadonlySet<string>,
): Expression
Constant-folds an operator expression whose arguments are (partly) constant.

Only deterministic, side-effect free operators may be folded: rand, uuid, struuid, bnode and now must survive to evaluation, and anything not listed is rebuilt unchanged. Only the folds sound under SPARQL's error handling are applied - notably = folds to true for two identical terms but never to false, comparing unsupported datatypes raising an error, and an error is not false in every context (COALESCE(Error, false, true) == false).
Parameters
- c: TransformationContext
  The transformation context
- operator: string
  The operator to fold
- args: Expression[]
  Its arguments, already substituted into
- boundVariables: ReadonlySet<string> = ...
  The variables known to be bound here, which is the only thing that makes sameTerm(?x, ?x) decidable: it is true of a bound ?x and an error of an unbound one
Returns Expression
the folded expression, or the operator rebuilt over its arguments
- Defined in lib/utils/partialExpressionEvaluation.ts:213