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package stdlib
import (
"fmt"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/function"
"github.com/zclconf/go-cty/cty/gocty"
)
var HasIndexFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "collection",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
},
{
Name: "key",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
},
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
collTy := args[0].Type()
if !(collTy.IsTupleType() || collTy.IsListType() || collTy.IsMapType() || collTy == cty.DynamicPseudoType) {
return cty.NilType, fmt.Errorf("collection must be a list, a map or a tuple")
}
return cty.Bool, nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
return args[0].HasIndex(args[1]), nil
},
})
var IndexFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "collection",
Type: cty.DynamicPseudoType,
},
{
Name: "key",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
},
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
collTy := args[0].Type()
key := args[1]
keyTy := key.Type()
switch {
case collTy.IsTupleType():
if keyTy != cty.Number && keyTy != cty.DynamicPseudoType {
return cty.NilType, fmt.Errorf("key for tuple must be number")
}
if !key.IsKnown() {
return cty.DynamicPseudoType, nil
}
var idx int
err := gocty.FromCtyValue(key, &idx)
if err != nil {
return cty.NilType, fmt.Errorf("invalid key for tuple: %s", err)
}
etys := collTy.TupleElementTypes()
if idx >= len(etys) || idx < 0 {
return cty.NilType, fmt.Errorf("key must be between 0 and %d inclusive", len(etys))
}
return etys[idx], nil
case collTy.IsListType():
if keyTy != cty.Number && keyTy != cty.DynamicPseudoType {
return cty.NilType, fmt.Errorf("key for list must be number")
}
return collTy.ElementType(), nil
case collTy.IsMapType():
if keyTy != cty.String && keyTy != cty.DynamicPseudoType {
return cty.NilType, fmt.Errorf("key for map must be string")
}
return collTy.ElementType(), nil
default:
return cty.NilType, fmt.Errorf("collection must be a list, a map or a tuple")
}
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
has, err := HasIndex(args[0], args[1])
if err != nil {
return cty.NilVal, err
}
if has.False() { // safe because collection and key are guaranteed known here
return cty.NilVal, fmt.Errorf("invalid index")
}
return args[0].Index(args[1]), nil
},
})
var LengthFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "collection",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
},
},
Type: func(args []cty.Value) (ret cty.Type, err error) {
collTy := args[0].Type()
if !(collTy.IsTupleType() || collTy.IsListType() || collTy.IsMapType() || collTy.IsSetType() || collTy == cty.DynamicPseudoType) {
return cty.NilType, fmt.Errorf("collection must be a list, a map or a tuple")
}
return cty.Number, nil
},
Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
return args[0].Length(), nil
},
})
// HasIndex determines whether the given collection can be indexed with the
// given key.
func HasIndex(collection cty.Value, key cty.Value) (cty.Value, error) {
return HasIndexFunc.Call([]cty.Value{collection, key})
}
// Index returns an element from the given collection using the given key,
// or returns an error if there is no element for the given key.
func Index(collection cty.Value, key cty.Value) (cty.Value, error) {
return IndexFunc.Call([]cty.Value{collection, key})
}
// Length returns the number of elements in the given collection.
func Length(collection cty.Value) (cty.Value, error) {
return LengthFunc.Call([]cty.Value{collection})
}
|
