/
functions_conversions.go
96 lines (89 loc) · 3.14 KB
/
functions_conversions.go
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package hclfuncs
import (
"reflect"
"strconv"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
"github.com/zclconf/go-cty/cty/function"
)
var TypeType = cty.Capsule("type", reflect.TypeOf(cty.Type{}))
func MakeToFunc(wantTy cty.Type) function.Function {
return function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "v",
Type: cty.DynamicPseudoType,
AllowNull: true,
AllowMarked: true,
AllowDynamicType: true,
},
},
Type: func(args []cty.Value) (cty.Type, error) {
gotTy := args[0].Type()
if gotTy.Equals(wantTy) {
return wantTy, nil
}
conv := convert.GetConversionUnsafe(args[0].Type(), wantTy)
if conv == nil {
switch {
case gotTy.IsTupleType() && wantTy.IsTupleType():
return cty.NilType, function.NewArgErrorf(0, "incompatible tuple type for conversion: %s", convert.MismatchMessage(gotTy, wantTy))
case gotTy.IsObjectType() && wantTy.IsObjectType():
return cty.NilType, function.NewArgErrorf(0, "incompatible object type for conversion: %s", convert.MismatchMessage(gotTy, wantTy))
default:
return cty.NilType, function.NewArgErrorf(0, "cannot convert %s to %s", gotTy.FriendlyName(), wantTy.FriendlyNameForConstraint())
}
}
// If a conversion is available then everything is fine.
return wantTy, nil
},
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
// We didn't set "AllowUnknown" on our argument, so it is guaranteed
// to be known here but may still be null.
ret, err := convert.Convert(args[0], retType)
if err != nil {
val, _ := args[0].UnmarkDeep()
gotTy := val.Type()
switch {
case gotTy == cty.String && wantTy == cty.Bool:
what := "string"
if !val.IsNull() {
what = strconv.Quote(val.AsString())
}
return cty.NilVal, function.NewArgErrorf(0, `cannot convert %s to bool; only the strings "true" or "false" are allowed`, what)
case gotTy == cty.String && wantTy == cty.Number:
what := "string"
if !val.IsNull() {
what = strconv.Quote(val.AsString())
}
return cty.NilVal, function.NewArgErrorf(0, `cannot convert %s to number; given string must be a decimal representation of a number`, what)
default:
return cty.NilVal, function.NewArgErrorf(0, "cannot convert %s to %s", gotTy.FriendlyName(), wantTy.FriendlyNameForConstraint())
}
}
return ret, nil
},
})
}
// TypeFunc returns an encapsulated value containing its argument's type. This
// value is marked to allow us to limit the use of this function at the moment
// to only a few supported use cases.
var TypeFunc = function.New(&function.Spec{
Params: []function.Parameter{
{
Name: "value",
Type: cty.DynamicPseudoType,
AllowDynamicType: true,
AllowUnknown: true,
AllowNull: true,
},
},
Type: function.StaticReturnType(TypeType),
Impl: func(args []cty.Value, retType cty.Type) (cty.Value, error) {
givenType := args[0].Type()
return cty.CapsuleVal(TypeType, &givenType).Mark(TypeType), nil
},
})
func Type(input []cty.Value) (cty.Value, error) {
return TypeFunc.Call(input)
}