[Libguestfs] [PATCH v2 1/2] mltools: JSON: Implement JSON.Null.

[Richard W.M. Jones]

Implements the ‘null’ value.
---
 common/mltools/JSON.ml  | 2 ++
 common/mltools/JSON.mli | 1 +
 2 files changed, 3 insertions(+)

diff --git a/common/mltools/JSON.ml b/common/mltools/JSON.ml
index 8c2e695e2..7418f1372 100644
--- a/common/mltools/JSON.ml
+++ b/common/mltools/JSON.ml
@@ -20,6 +20,7 @@
 
 type field = string * json_t
 and json_t =
+  | Null
   | String of string
   | Int of int64
   | Float of float
@@ -106,6 +107,7 @@ and output_list fields ~fmt ~indent =
   ^ (print_dict_before_end ~fmt ~indent ~size) ^ (print_indent ~fmt ~indent) ^ "]"
 
 and output_field ~indent ~fmt = function
+  | Null -> "null"
   | String s -> json_quote_string s
   | Int i -> Int64.to_string i
   (* The JSON standard permits either "1" or "1.0" but not "1.".
diff --git a/common/mltools/JSON.mli b/common/mltools/JSON.mli
index c85b786ff..810de6460 100644
--- a/common/mltools/JSON.mli
+++ b/common/mltools/JSON.mli
@@ -20,6 +20,7 @@
 
 type field = string * json_t    (** ["field": "value"] *)
 and json_t =                    (** JSON value. *)
+  | Null                        (** special null value *)
   | String of string            (** string value, eg. ["string"] *)
   | Int of int64                (** int value, eg. [99] *)
   | Float of float              (** floating point value, eg. [9.9] *)
-- 
2.18.0