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ferret/pkg/stdlib/arrays/minus.go
2018-10-14 13:06:27 -04:00

63 lines
1.4 KiB
Go

package arrays
import (
"context"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/values"
)
// Minus return the difference of all arrays specified.
// @param arrays (Array, repeated) - An arbitrary number of arrays as multiple arguments (at least 2).
// @returns array (Array) - An array of values that occur in the first array, but not in any of the subsequent arrays.
// The order of the result array is undefined and should not be relied on. Duplicates will be removed.
func Minus(_ context.Context, args ...core.Value) (core.Value, error) {
err := core.ValidateArgs(args, 2, core.MaxArgs)
if err != nil {
return values.None, err
}
intersections := make(map[uint64]core.Value)
capacity := values.NewInt(0)
for idx, i := range args {
err := core.ValidateType(i, core.ArrayType)
if err != nil {
return values.None, err
}
arr := i.(*values.Array)
arr.ForEach(func(value core.Value, _ int) bool {
h := value.Hash()
// first array, fill out the map
if idx == 0 {
capacity = arr.Length()
intersections[h] = value
return true
}
_, exists := intersections[h]
// if it exists in the first array, remove it
if exists {
delete(intersections, h)
}
return true
})
}
result := values.NewArray(int(capacity))
for _, item := range intersections {
result.Push(item)
}
return result, nil
}