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