feat: Skip converting keys whose values are nil

README.org

@@ -18,15 +18,15 @@ the Emacs core library [[https://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/j
 
 It will then be gradually refactored so that it meets the
 specification defined below.
-* Library Completion Status [1/7]
+* Library Completion Status [2/7]
 - [X] Scalar
   - [X] Boolean
   - [X] Integer
   - [X] Float
   - [X] String
   - [X] Date
   - [X] Date + Time with Offset
-- [ ] Nil
+- [X] Nil
 - [ ] Arrays
 - [ ] Array of Arrays
 - [ ] Tables
@@ -241,6 +241,43 @@ odt3 = 1979-05-27T00:32:00.999999-07:00
 :   "odt2": "1979-05-27T00:32:00-07:00",
 :   "odt3": "1979-05-27T00:32:00.999999-07:00"
 : }
+** DONE Nil
+CLOSED: [2022-04-29 Fri 00:11]
+**** S-expression
+#+begin_src emacs-lisp :eval no :noweb-ref nil-value
+'((key1 . 123)
+  (key2 . nil)
+  (key3 . "abc")
+  (key4 . :false)
+  (key5 . t))
+#+end_src
+**** TOML
+#+begin_src emacs-lisp :noweb yes :exports results :wrap src toml
+(tomelr-encode
+  <<nil-value>>)
+#+end_src
+
+#+RESULTS:
+#+begin_src toml
+key1 = 123
+key3 = "abc"
+key4 = false
+key5 = true
+#+end_src
+**** JSON Reference
+#+begin_src emacs-lisp :noweb yes :exports results
+(json-encode-pretty
+  <<nil-value>>)
+#+end_src
+
+#+RESULTS:
+: {
+:   "key1": 123,
+:   "key2": null,
+:   "key3": "abc",
+:   "key4": false,
+:   "key5": true
+: }
 ** TOML Arrays: Lists
 https://toml.io/en/v1.0.0#array
 *** Lists
@@ -827,36 +864,6 @@ booleans = [true, false]
   ]
 }
 #+end_example
-** Nil
-**** S-expression
-#+begin_src emacs-lisp :eval no :noweb-ref nil-value
-'((key1 . 123)
-  (key2 . nil)
-  (key3 . "abc")
-  (key4 . :false)
-  (key5 . t))
-#+end_src
-**** TOML
-#+begin_src toml
-key1 = 123
-key3 = "abc"
-key4 = false
-key5 = true
-#+end_src
-**** JSON Reference
-#+begin_src emacs-lisp :noweb yes :exports results
-(json-encode-pretty
-  <<nil-value>>)
-#+end_src
-
-#+RESULTS:
-: {
-:   "key1": 123,
-:   "key2": null,
-:   "key3": "abc",
-:   "key4": false,
-:   "key5": true
-: }
 ** P-lists
 **** S-expression
 #+begin_src emacs-lisp :eval no :noweb-ref p-list

test/all-tests.el

@@ -22,3 +22,4 @@
 (setq load-prefer-newer t)
 
 (require 'tscalar)
+(require 'tnil)

test/tnil.el

@@ -0,0 +1,48 @@
+;; -*- lexical-binding: t; -*-
+
+;; Authors: Kaushal Modi <kaushal.modi@gmail.com>
+
+;; This file is not part of GNU Emacs.
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Test removal of keys with nil value.
+
+;;; Code:
+(require 'tomelr)
+
+;;;; Key with nil value
+(ert-deftest test-nil ()
+  (let ((inp '(((nil_key . nil))
+               ((bool1 . t)
+                (int . +99)
+                (nil_key1 . nil)
+                (bool2 . :false)
+                (nil_key2 . nil)
+                (bool3 . "false"))
+               ))
+        (ref '(""
+               "bool1 = true
+int = 99
+bool2 = false
+bool3 = false"))
+        out)
+    (dolist (el inp)
+      (push (tomelr-encode el) out))
+    (should (equal ref (nreverse out)))))
+
+
+(provide 'tnil)

tomelr.el

@@ -225,10 +225,12 @@ Signal `tomelr-key-format' if it cannot be encoded as a string."
 ;;;; Objects
 (defun tomelr--print-pair (key val)
   "Insert TOML representation of KEY-VAL pair at point."
-  (tomelr--print-indentation) ;Newline before each key in a key-value pair
-  (tomelr--print-key key)
-  (insert tomelr--print-keyval-separator)
-  (tomelr--print val))
+  ;; (message "[tomelr--print-pair DBG] key = %S, val = %S" key val)
+  (when val                     ;Don't print the key if val is nil
+    (tomelr--print-indentation) ;Newline before each key in a key-value pair
+    (tomelr--print-key key)
+    (insert tomelr--print-keyval-separator)
+    (tomelr--print val)))
 
 (defun tomelr--print-map (map)
   "Insert TOML object representation of MAP at point.
@@ -311,6 +313,7 @@ ARRAY can also be a list."
         ((hash-table-p object)  (tomelr--print-unordered-map object))
         ((signal 'tomelr-error (list object)))))
 
+
 
 ;;; User API
 (defun tomelr-encode (object)