attr: Added IsNull() and IsUnknown() methods to the Value inter…

…face type

Reference: #193

.changelog/pending.txt

@@ -0,0 +1,7 @@
+```release-note:breaking-change
+attr: The `Value` interface type now requires `IsNull() bool` and `IsUnknown() bool` methods for implementations.
+```
+
+```release-note:enhancement
+attr: Added `IsNull()` and `IsUnknown()` methods to the `Value` interface type
+```

attr/value.go

@@ -18,4 +18,10 @@ type Value interface {
 	// Equal must return true if the Value is considered semantically equal
 	// to the Value passed as an argument.
 	Equal(Value) bool
+
+	// IsNull returns true if the Value is null.
+	IsNull() bool
+
+	// IsUnknown returns true if the Value is unknown.
+	IsUnknown() bool
 }

types/bool.go

@@ -74,3 +74,13 @@ func (b Bool) Equal(other attr.Value) bool {
 	}
 	return b.Value == o.Value
 }
+
+// IsNull returns true if the Bool is null.
+func (b Bool) IsNull() bool {
+	return b.Null
+}
+
+// IsUnknown returns true if the Bool is unknown.
+func (b Bool) IsUnknown() bool {
+	return b.Unknown
+}

types/float64.go

@@ -114,6 +114,16 @@ func (f Float64) Equal(other attr.Value) bool {
 	return f.Value == o.Value
 }
 
+// IsNull returns true if the Float64 is null.
+func (f Float64) IsNull() bool {
+	return f.Null
+}
+
+// IsUnknown returns true if the Float64 is unknown.
+func (f Float64) IsUnknown() bool {
+	return f.Unknown
+}
+
 // ToTerraformValue returns the data contained in the Float64 as a float64.
 // If Unknown is true, it returns a tftypes.UnknownValue. If Null is true, it
 // returns nil.

types/int64.go

@@ -127,6 +127,16 @@ func (i Int64) Equal(other attr.Value) bool {
 	return i.Value == o.Value
 }
 
+// IsNull returns true if the Int64 is null.
+func (i Int64) IsNull() bool {
+	return i.Null
+}
+
+// IsUnknown returns true if the Int64 is unknown.
+func (i Int64) IsUnknown() bool {
+	return i.Unknown
+}
+
 // ToTerraformValue returns the data contained in the Int64 as a int64.
 // If Unknown is true, it returns a tftypes.UnknownValue. If Null is true, it
 // returns nil.

types/list.go

@@ -211,3 +211,13 @@ func (l List) Equal(o attr.Value) bool {
 	}
 	return true
 }
+
+// IsNull returns true if the List is null.
+func (l List) IsNull() bool {
+	return l.Null
+}
+
+// IsUnknown returns true if the List is unknown.
+func (l List) IsUnknown() bool {
+	return l.Unknown
+}

types/map.go

@@ -224,3 +224,13 @@ func (m Map) Equal(o attr.Value) bool {
 	}
 	return true
 }
+
+// IsNull returns true if the Map is null.
+func (m Map) IsNull() bool {
+	return m.Null
+}
+
+// IsUnknown returns true if the Map is unknown.
+func (m Map) IsUnknown() bool {
+	return m.Unknown
+}

types/number.go

@@ -78,3 +78,13 @@ func (n Number) Equal(other attr.Value) bool {
 	}
 	return n.Value.Cmp(o.Value) == 0
 }
+
+// IsNull returns true if the Number is null.
+func (n Number) IsNull() bool {
+	return n.Null
+}
+
+// IsUnknown returns true if the Number is unknown.
+func (n Number) IsUnknown() bool {
+	return n.Unknown
+}

types/object.go

@@ -271,3 +271,13 @@ func (o Object) Equal(c attr.Value) bool {
 
 	return true
 }
+
+// IsNull returns true if the Object is null.
+func (o Object) IsNull() bool {
+	return o.Null
+}
+
+// IsUnknown returns true if the Object is unknown.
+func (o Object) IsUnknown() bool {
+	return o.Unknown
+}

types/set.go

@@ -268,6 +268,16 @@ func (s Set) Equal(o attr.Value) bool {
 	return true
 }
 
+// IsNull returns true if the Set is null.
+func (s Set) IsNull() bool {
+	return s.Null
+}
+
+// IsUnknown returns true if the Set is unknown.
+func (s Set) IsUnknown() bool {
+	return s.Unknown
+}
+
 func (s Set) contains(v attr.Value) bool {
 	for _, elem := range s.Elems {
 		if elem.Equal(v) {

types/string.go

@@ -70,3 +70,13 @@ func (s String) Equal(other attr.Value) bool {
 	}
 	return s.Value == o.Value
 }
+
+// IsNull returns true if the String is null.
+func (s String) IsNull() bool {
+	return s.Null
+}
+
+// IsUnknown returns true if the String is unknown.
+func (s String) IsUnknown() bool {
+	return s.Unknown
+}