databricks-cli/libs/dyn/visit_map.go

90 lines
2.6 KiB
Go
Raw Normal View History

package dyn
import (
"fmt"
"slices"
)
// MapFunc is a function that maps a value to another value.
type MapFunc func(Path, Value) (Value, error)
// Foreach returns a [MapFunc] that applies the specified [MapFunc] to each
// value in a map or sequence and returns the new map or sequence.
// If the input is nil, it returns nil.
func Foreach(fn MapFunc) MapFunc {
return func(p Path, v Value) (Value, error) {
switch v.Kind() {
case KindNil:
return v, nil
case KindMap:
m := v.MustMap().Clone()
for _, pair := range m.Pairs() {
pk := pair.Key
pv := pair.Value
nv, err := fn(append(p, Key(pk.MustString())), pv)
if err != nil {
return InvalidValue, err
}
m.Set(pk, nv)
}
return NewValue(m, v.Locations()), nil
case KindSequence:
s := slices.Clone(v.MustSequence())
for i, value := range s {
var err error
s[i], err = fn(append(p, Index(i)), value)
if err != nil {
return InvalidValue, err
}
}
return NewValue(s, v.Locations()), nil
default:
return InvalidValue, fmt.Errorf("expected a map or sequence, found %s", v.Kind())
}
}
}
// Map applies a function to the value at the given path in the given value.
// It is identical to [MapByPath], except that it takes a string path instead of a [Path].
func Map(v Value, path string, fn MapFunc) (Value, error) {
p, err := NewPathFromString(path)
if err != nil {
return InvalidValue, err
}
return MapByPath(v, p, fn)
}
// MapByPath applies a function to the value at the given path in the given value.
// It is identical to [MapByPattern], except that it takes a [Path] instead of a [Pattern].
// This means it only matches a single value, not a pattern of values.
func MapByPath(v Value, p Path, fn MapFunc) (Value, error) {
return MapByPattern(v, NewPatternFromPath(p), fn)
}
// MapByPattern applies a function to the values whose paths match the given pattern in the given value.
// If successful, it returns the new value with all intermediate values copied and updated.
//
// If the pattern contains a key that doesn't exist, or an index that is out of bounds,
// it returns the original value and no error.
//
// If the pattern is invalid for the given value, it returns InvalidValue and an error.
func MapByPattern(v Value, p Pattern, fn MapFunc) (Value, error) {
nv, err := visit(v, EmptyPath, p, visitOptions{
fn: fn,
})
// Check for success.
if err == nil {
return nv, nil
}
// Return original value if:
// - any map or sequence is a nil, or
// - a key or index is missing
if IsCannotTraverseNilError(err) || IsNoSuchKeyError(err) || IsIndexOutOfBoundsError(err) {
return v, nil
}
return nv, err
}