[elpa] externals/tomelr 7d8d41f15b 19/84: feat: Encode to multi-line TOML string automatically

[ELPA Syncer]

branch: externals/tomelr
commit 7d8d41f15b6d5a2d2325160490482b133c56f845
Author: Kaushal Modi <kaushal.modi@gmail.com>
Commit: Kaushal Modi <kaushal.modi@gmail.com>

    feat: Encode to multi-line TOML string automatically
    
    .. if the string has newlines or quote chars.
---
 README.org      | 20 +++++++++++----
 test/tscalar.el | 16 ++++++++++++
 tomelr.el       | 77 ++++++++++++++++++++++++++++++++++++---------------------
 3 files changed, 80 insertions(+), 33 deletions(-)

diff --git a/README.org b/README.org
index 176979b7ed..6583e6dcca 100644
--- a/README.org
+++ b/README.org
@@ -23,7 +23,7 @@ specification defined below.
   - [X] Boolean
   - [X] Integer
   - [X] Float
-  - [ ] String
+  - [X] String
   - [ ] Date + Time with Offset
   - [ ] Date
   - [ ] Nil
@@ -149,15 +149,24 @@ flt7 = 6.626e-34
 :   "flt6": -0.02,
 :   "flt7": 6.626e-34
 : }
-*** String
+*** DONE String
+CLOSED: [2022-04-28 Thu 22:10]
 https://toml.io/en/v1.0.0#string
 **** S-expression
 #+begin_src emacs-lisp :eval no :noweb-ref scalar-string
-'((str . "Roses are red\nViolets are blue"))
+'((str1 . "Roses are red")
+  (str2 . "Roses are red\nViolets are blue"))
 #+end_src
 **** TOML
+#+begin_src emacs-lisp :noweb yes :exports results :wrap src toml
+(tomelr-encode
+  <<scalar-string>>)
+#+end_src
+
+#+RESULTS:
 #+begin_src toml
-str = """
+str1 = "Roses are red"
+str2 = """
 Roses are red
 Violets are blue"""
 #+end_src
@@ -169,7 +178,8 @@ Violets are blue"""
 
 #+RESULTS:
 : {
-:   "str": "Roses are red\nViolets are blue"
+:   "str1": "Roses are red",
+:   "str2": "Roses are red\nViolets are blue"
 : }
 *** Date + Time with Offset
 https://toml.io/en/v1.0.0#offset-date-time
diff --git a/test/tscalar.el b/test/tscalar.el
index a052eff7db..27fd940d00 100644
--- a/test/tscalar.el
+++ b/test/tscalar.el
@@ -74,5 +74,21 @@
       (push (tomelr-encode el) out))
     (should (equal ref (nreverse out)))))
 
+;;;; Scalar - String
+(ert-deftest test-scalar-string ()
+  (let ((inp '(((string1 . "Roses are red"))
+               ((string2 . "Roses are red\nViolets are blue")) ;Newline in 
string
+               ((string3 . "\"Hello!\"")))) ;Quote in string
+        (ref '("string1 = \"Roses are red\""
+               "string2 = \"\"\"
+Roses are red
+Violets are blue\"\"\""
+               "string3 = \"\"\"
+\"Hello!\"\"\"\""))
+        out)
+    (dolist (el inp)
+      (push (tomelr-encode el) out))
+    (should (equal ref (nreverse out)))))
+
 
 (provide 'tscalar)
diff --git a/tomelr.el b/tomelr.el
index 805dcdb8a9..342ba01a5d 100644
--- a/tomelr.el
+++ b/tomelr.el
@@ -130,35 +130,56 @@ Return nil if KEYWORD is not recognized as a TOML 
keyword."
     (and keyword (insert keyword))))
 
 ;;;; Strings
-(defconst tomelr-special-chars
-  '((?\" . ?\")
-    (?\\ . ?\\)
-    (?b . ?\b)
-    (?f . ?\f)
-    (?n . ?\n)
-    (?r . ?\r)
-    (?t . ?\t))
-  "Characters which are escaped in TOML, with their Elisp counterparts.")
-
-(defun tomelr--print-string (string &optional from)
+(defun tomelr--print-string (string &optional trim-init-chars)
   "Insert a TOML representation of STRING at point.
-FROM is the index of STRING to start from and defaults to 0."
-  ;; (message "[tomelr--print-string DBG] string = %s" string)
-  (insert ?\")
-  (goto-char (prog1 (point) (princ string)))
-  (and from (delete-char from))
-  ;; Escape only quotation mark, backslash, and the control
-  ;; characters U+0000 to U+001F (RFC 4627, ECMA-404).
-  (while (re-search-forward (rx (in ?\" ?\\ cntrl)) nil 'move)
-    (let ((char (preceding-char)))
-      (delete-char -1)
-      (insert ?\\ (or
-                   ;; Special TOML character (\n, \r, etc.).
-                   (car (rassq char tomelr-special-chars))
-                   ;; Fallback: UCS code point in \uNNNN form.
-                   (format "u%04x" char)))))
-  (insert ?\")
-  string)
+
+If TRIM-INIT-CHARS is positive, those many initial characters
+of the STRING are not inserted.
+
+Return the same STRING passed as input."
+  (let ((special-chars '((?b . ?\b)     ;U+0008
+                         (?f . ?\f)     ;U+000C
+                         (?\\ . ?\\)))
+        special-chars-re
+        begin-q end-q)
+    ;; Use multi-line string quotation if the string contains a " char
+    ;; or a newline.
+    (if (string-match-p "\n\\|\"" string)
+        (progn                          ;Triple quotation """STRING"""
+          ;; From https://toml.io/en/v1.0.0#string, Any Unicode
+          ;; character may be used except those that must be escaped:
+          ;; backslash and the control characters other than tab, line
+          ;; feed, and carriage return (U+0000 to U+0008, U+000B,
+          ;; U+000C, U+000E to U+001F, U+007F).
+          (setq special-chars-re (rx (in ?\\
+                                         (?\u0000 . ?\u0008)
+                                         ?\u000B ?\u000C
+                                         (?\u000E . ?\u001F)
+                                         ?\u007F)))
+          (setq begin-q "\"\"\"\n")
+          (setq end-q "\"\"\""))
+      (progn                            ;Basic quotation "STRING"
+        (setq special-chars-re (rx (in ?\" ?\\ cntrl ?\u007F))) ;cntrl is same 
as (?\u0000 . ?\u001F)
+        (push '(?\" . ?\") special-chars)
+        (push '(?t . ?\t) special-chars) ;U+0009
+        (push '(?n . ?\n) special-chars) ;U+000A
+        (push '(?r . ?\r) special-chars) ;U+000D
+        (setq begin-q "\"")
+        (setq end-q begin-q)))
+    ;; (message "[tomelr--print-string DBG] string = `%s'" string)
+    (insert begin-q)
+    (goto-char (prog1 (point) (princ string)))
+    (and trim-init-chars (delete-char trim-init-chars))
+    (while (re-search-forward special-chars-re nil :noerror)
+      (let ((char (preceding-char)))
+        (delete-char -1)
+        (insert ?\\ (or
+                     ;; Escape special characters
+                     (car (rassq char special-chars))
+                     ;; Fallback: UCS code point in \uNNNN form.
+                     (format "u%04x" char)))))
+    (insert end-q)
+    string))
 
 (defun tomelr-encode-string (string)
   "Return a TOML representation of STRING."