/
func_arr.go
311 lines (255 loc) · 6.24 KB
/
func_arr.go
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package expr
import (
"fmt"
"reflect"
"sort"
"strings"
"github.com/PaesslerAG/gval"
)
func ArrayFunctions() []gval.Language {
return []gval.Language{
gval.Function("push", push),
gval.Function("pop", pop),
gval.Function("shift", shift),
gval.Function("count", count),
gval.Function("has", Has),
gval.Function("hasAll", hasAll),
gval.Function("find", find),
gval.Function("sort", sortSlice),
gval.Function("splice", splice),
}
}
// push adds a value to the end of slice, returns copy
func push(arr interface{}, nn ...interface{}) (out interface{}, err error) {
if arr == nil {
// If base is empty, return pushed items directly
return nn, nil
} else if i, is := arr.([]interface{}); is {
// Simple append if we're dealing with []interface{} base
return append(i, nn...), nil
} else if arr, err = toSlice(arr); err != nil {
return
}
if stv, is := arr.([]TypedValue); is {
// slice of typed values, this will make things easier
for _, n := range nn {
if tv, is := n.(TypedValue); is {
stv = append(stv, tv)
} else {
// wrap unknown types...
stv = append(stv, Must(Typify(n)))
}
}
return stv, nil
}
var (
c = reflect.ValueOf(arr)
nval = reflect.MakeSlice(c.Type(), c.Len()+len(nn), c.Cap()+len(nn))
)
reflect.Copy(nval, c)
for i, n := range nn {
nt := reflect.ValueOf(n).Type()
it := nval.Index(c.Len() + i).Type()
if nt != it {
return nil, fmt.Errorf("can not push %v to %v slice", nt, it)
}
nval.Index(c.Len() + i).Set(reflect.ValueOf(n))
}
return nval.Interface(), nil
}
// pop takes the last value in slice, does not modify original
func pop(arr interface{}) (out interface{}, err error) {
if arr, err = toSlice(arr); err != nil {
return
}
c := reflect.ValueOf(arr)
if c.Len() == 0 {
return nil, nil
}
return c.Index(c.Len() - 1).Interface(), nil
}
// shifts takes the first value in slice, does not modify original
func shift(arr interface{}) (out interface{}, err error) {
if arr, err = toSlice(arr); err != nil {
return
}
c := reflect.ValueOf(arr)
if c.Len() == 0 {
return nil, nil
}
return c.Index(0).Interface(), nil
}
// count gets the count of occurrences in the first params(can be string, slice)
// If given only one parameter then it returns length as count
func count(arr interface{}, v ...interface{}) (count int, err error) {
typeErr := fmt.Errorf("unexpected type: %T, expecting slice", arr)
arr = UntypedValue(arr)
if stv, is := arr.([]TypedValue); is {
if len(v) == 0 {
return len(stv), nil
}
for _, vv := range v {
if occ, err := find(stv, vv); err != nil {
return 0, err
} else if occ != -1 {
count++
}
}
return count, nil
}
var (
occ int
c = reflect.ValueOf(arr)
)
switch c.Kind() {
case reflect.String:
if len(v) == 0 {
return len(c.String()), nil
}
for _, ww := range v {
count += strings.Count(c.String(), reflect.ValueOf(ww).String())
}
return
case reflect.Slice:
if len(v) == 0 {
return c.Len(), nil
}
for _, vv := range v {
if occ, err = find(arr, vv); err != nil {
return 0, err
} else if occ != -1 {
count++
}
}
default:
return 0, typeErr
}
return
}
// has finds any occurrence of the values in slice or key in a map
func Has(arr interface{}, vv ...interface{}) (b bool, err error) {
arr = UntypedValue(arr)
if isMap(arr) {
for _, v := range vv {
if reflect.ValueOf(arr).MapIndex(reflect.ValueOf(v)).IsValid() {
return true, nil
}
}
return
}
var c int
if c, err = count(arr, vv...); err != nil {
return
}
return c > 0, nil
}
// hasAll finds all the occurrences in the slice
func hasAll(arr interface{}, v ...interface{}) (b bool, err error) {
if arr, err = toSlice(arr); err != nil {
return
}
var c int
if c, err = count(arr, v...); err != nil {
return
}
return c == len(v), nil
}
// find takes a value and gets the position in slice
// if no results, returns -1
func find(arr interface{}, v interface{}) (p int, err error) {
if arr, err = toSlice(arr); err != nil {
return
}
for p = 0; p < reflect.ValueOf(arr).Len(); p++ {
c := reflect.ValueOf(arr)
if UntypedValue(c.Index(p).Interface()) == v {
return
}
}
return -1, nil
}
// splice slices slice
func splice(arr interface{}, s, e float64) interface{} {
var (
err error
start = int(s)
end = int(e)
)
if arr, err = toSlice(arr); err != nil {
return nil
}
v := reflect.ValueOf(arr)
if start >= v.Len() {
return v.Interface()
}
if end == -1 || end > v.Len() {
end = v.Len()
}
return v.Slice(start, end).Interface()
}
// sortSlice sorts slice
func sortSlice(arr interface{}, desc bool) (out interface{}, err error) {
if arr, err = toSlice(arr); err != nil {
return
}
// sort slice of native type values
var (
c = reflect.ValueOf(arr)
v = reflect.MakeSlice(c.Type(), c.Len(), c.Cap())
vi = v.Interface()
)
reflect.Copy(v, c)
// sortStable sorts the slice x using the provided less
// function, keeping equal elements in their original order
//
// sort the array if error is nil;
// we trap the error(s) in the outer scope from the less function,
// and returning the last error at a time since all error will the same in almost every scenario.
sort.SliceStable(vi, func(i, j int) bool {
if err != nil {
return false
}
var (
nVal = v.Index(i)
mVal = v.Index(j)
)
if desc {
nVal = v.Index(j)
mVal = v.Index(i)
}
switch getKind(vi) {
case reflect.String:
return nVal.String() < mVal.String()
case reflect.Int, reflect.Int32, reflect.Int64:
return nVal.Int() < mVal.Int()
case reflect.Float32, reflect.Float64:
return nVal.Float() < mVal.Float()
default:
// sort slice of typed values
if stv, is := vi.([]TypedValue); is {
if casted, ok := stv[i].(Comparable); ok {
var cmp int
cmp, err = casted.Compare(stv[j])
if err != nil {
return false
}
if desc {
return cmp > 0
} else {
return cmp < 0
}
} else {
err = fmt.Errorf("cannot compare %s and %s: unknown state", stv[i].Type(), stv[j].Type())
return false
}
}
err = fmt.Errorf("cannot compare %s and %s: unknown state", getKind(nVal), getKind(mVal))
return false
}
})
// returns error from less function
if err != nil {
return arr, err
}
return vi, nil
}