73 lines
2.5 KiB
Go
73 lines
2.5 KiB
Go
// Mgmt
|
|
// Copyright (C) James Shubin and the project contributors
|
|
// Written by James Shubin <james@shubin.ca> and the project contributors
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
//
|
|
// Additional permission under GNU GPL version 3 section 7
|
|
//
|
|
// If you modify this program, or any covered work, by linking or combining it
|
|
// with embedded mcl code and modules (and that the embedded mcl code and
|
|
// modules which link with this program, contain a copy of their source code in
|
|
// the authoritative form) containing parts covered by the terms of any other
|
|
// license, the licensors of this program grant you additional permission to
|
|
// convey the resulting work. Furthermore, the licensors of this program grant
|
|
// the original author, James Shubin, additional permission to update this
|
|
// additional permission if he deems it necessary to achieve the goals of this
|
|
// additional permission.
|
|
|
|
package core
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"math"
|
|
|
|
"github.com/purpleidea/mgmt/lang/funcs/simple"
|
|
"github.com/purpleidea/mgmt/lang/types"
|
|
)
|
|
|
|
const (
|
|
// ListLookupFuncName is the name this function is registered as.
|
|
ListLookupFuncName = "list_lookup"
|
|
)
|
|
|
|
func init() {
|
|
simple.Register(ListLookupFuncName, &simple.Scaffold{
|
|
T: types.NewType("func(list []?1, index int) ?1"),
|
|
F: ListLookup,
|
|
})
|
|
}
|
|
|
|
// ListLookup returns the value corresponding to the input index in the list.
|
|
func ListLookup(ctx context.Context, input []types.Value) (types.Value, error) {
|
|
l := input[0].(*types.ListValue)
|
|
index := input[1].Int()
|
|
zero := l.Type().Val.New() // the zero value
|
|
|
|
// TODO: should we handle overflow by returning zero?
|
|
if index > math.MaxInt { // max int size varies by arch
|
|
return nil, fmt.Errorf("list index overflow, got: %d, max is: %d", index, math.MaxInt)
|
|
}
|
|
if index < 0 { // lists can't have negative indexes (for now)
|
|
return nil, fmt.Errorf("list index negative, got: %d", index)
|
|
}
|
|
|
|
val, exists := l.Lookup(int(index))
|
|
if !exists {
|
|
return zero, nil
|
|
}
|
|
return val, nil
|
|
}
|