60 lines
1.9 KiB
Go
60 lines
1.9 KiB
Go
package function
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import (
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"errors"
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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/function/stdlib"
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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: "value",
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Type: cty.DynamicPseudoType,
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AllowDynamicType: true,
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AllowUnknown: true,
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},
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},
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Type: func(args []cty.Value) (cty.Type, error) {
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collTy := args[0].Type()
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switch {
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case collTy == cty.String || collTy.IsTupleType() || collTy.IsObjectType() || collTy.IsListType() || collTy.IsMapType() || collTy.IsSetType() || collTy == cty.DynamicPseudoType:
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return cty.Number, nil
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default:
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return cty.Number, errors.New("argument must be a string, a collection type, or a structural type")
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}
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},
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Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
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coll := args[0]
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collTy := args[0].Type()
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switch {
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case collTy == cty.DynamicPseudoType:
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return cty.UnknownVal(cty.Number), nil
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case collTy.IsTupleType():
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l := len(collTy.TupleElementTypes())
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return cty.NumberIntVal(int64(l)), nil
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case collTy.IsObjectType():
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l := len(collTy.AttributeTypes())
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return cty.NumberIntVal(int64(l)), nil
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case collTy == cty.String:
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// We'll delegate to the cty stdlib strlen function here, because
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// it deals with all of the complexities of tokenizing unicode
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// grapheme clusters.
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return stdlib.Strlen(coll)
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case collTy.IsListType() || collTy.IsSetType() || collTy.IsMapType():
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return coll.Length(), nil
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default:
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// Should never happen, because of the checks in our Type func above
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return cty.UnknownVal(cty.Number), errors.New("impossible value type for length(...)")
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}
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},
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})
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// Length returns the number of elements in the given collection or number of
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// Unicode characters in the given string.
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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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