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ferret/pkg/stdlib/arrays/unshift.go
Tim Voronov 1af8b37a0f
New type system ()
* New type system

* Fixed dot notation for HTML elements
2019-02-13 12:31:18 -05:00

81 lines
1.6 KiB
Go

package arrays
import (
"context"
"github.com/MontFerret/ferret/pkg/runtime/core"
"github.com/MontFerret/ferret/pkg/runtime/values"
"github.com/MontFerret/ferret/pkg/runtime/values/types"
)
// Unshift prepends value to a given array.
// @param array (Array) - Target array.
// @param value (Read) - Target value to prepend.
// @param unique (Boolean, optional) - Optional value indicating whether a value must be unique to be prepended.
// Default is false.
// @returns (Array) - New array with prepended value.
func Unshift(_ context.Context, args ...core.Value) (core.Value, error) {
err := core.ValidateArgs(args, 2, 3)
if err != nil {
return values.None, err
}
err = core.ValidateType(args[0], types.Array)
if err != nil {
return values.None, err
}
arr := args[0].(*values.Array)
value := args[1]
uniq := values.False
if len(args) > 2 {
err = core.ValidateType(args[2], types.Boolean)
if err != nil {
return values.None, err
}
uniq = args[2].(values.Boolean)
}
result := values.NewArray(int(arr.Length() + 1))
if !uniq {
result.Push(value)
arr.ForEach(func(el core.Value, _ int) bool {
result.Push(el)
return true
})
} else {
ok := true
// let's just hope it's unique
// if not, we will terminate the loop and return a copy of an array
result.Push(value)
arr.ForEach(func(el core.Value, idx int) bool {
if el.Compare(value) != 0 {
result.Push(el)
return true
}
// not unique
ok = false
return false
})
if !ok {
// value is not unique, just return a new copy with same elements
return arr.Copy(), nil
}
}
return result, nil
}