Exemple #1
0
func (this *InitialProject) processItem(item value.AnnotatedValue, context *Context) bool {
	terms := this.plan.Terms()
	n := len(terms)

	if n > 1 {
		return this.processTerms(item, context)
	}

	if n == 0 {
		return this.sendItem(item)
	}

	// n == 1

	result := terms[0].Result()
	expr := result.Expression()

	if result.Star() && (expr == expression.SELF || expr == nil) {
		// Unprefixed star
		if item.Type() == value.OBJECT {
			return this.sendItem(item)
		} else {
			return this.sendItem(_EMPTY_ANNOTATED_VALUE)
		}
	} else if this.plan.Projection().Raw() {
		// Raw projection of an expression
		v, err := expr.Evaluate(item, context)
		if err != nil {
			context.Error(errors.NewEvaluationError(err, "projection"))
			return false
		}

		if result.As() == "" {
			return this.sendItem(value.NewAnnotatedValue(v))
		}

		sv := value.NewScopeValue(make(map[string]interface{}, 1), item)
		sv.SetField(result.As(), v)
		av := value.NewAnnotatedValue(sv)
		av.SetAttachment("projection", v)
		return this.sendItem(av)
	} else {
		// Any other projection
		return this.processTerms(item, context)
	}
}