[O] Add an optional HOLD argument to "n" Org macro (Was: [RFC] The "c" Org macro)

[Kaushal Modi]

I was writing something along the lines of this when I needed to specify the n macro to hold its previous value and not increment at all.

=====

* Week {{{n(wk)}}}: Python Basics

# 1

** {{{n}}}. Introduction to Python

# 1

** {{{n}}}. Core Elements of Programs

# 2

*** {{{n(,,hold)}}}.{{{n(topic,reset)}}}: Bindings

# 2.1

*** {{{n(,,hold)}}}.{{{n(topic)}}}: Strings

# 2.2

*** {{{n(,,hold)}}}.{{{n(topic)}}}: Input/Output

# 2.3

* Week {{{n(wk)}}}: Simple Programs

# 2

** {{{n}}}. Simple Algorithms

# 3

** {{{n}}}. Functions

# 4

* Week {{{n(wk)}}}: Structured Types

# 3

** {{{n}}}. Tuples and Lists

# 5

** {{{n}}}. Dictionaries

# 6

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Below is an informal diff to show how the hold feature was implemented.

diff --git a/lisp/org-macro.el b/lisp/org-macro.el

index 338c98811d..cc74cebd0a 100644

--- a/lisp/org-macro.el

+++ b/lisp/org-macro.el

@@ -40,7 +40,7 @@

 ;;   {{{property(node-property)}}},

 ;;   {{{input-file}}},

 ;;   {{{modification-time(format-string)}}},

-;;   {{{n(counter,reset}}}.

+;;   {{{n(counter,reset,hold}}}.

 

 ;; Upon exporting, "ox.el" will also provide {{{author}}}, {{{date}}},

 ;; {{{email}}} and {{{title}}} macros.

@@ -163,7 +163,7 @@ function installs the following ones: \"property\",

     ;; Initialize and install "n" macro.

     (org-macro--counter-initialize)

     (funcall update-templates

-     (cons "n" "(eval (org-macro--counter-increment \"$1\" \"$2\"))"))

+     (cons "n" "(eval (org-macro--counter-increment \"$1\" \"$2\" \"$3\"))"))

     (setq org-macro-templates templates)))

 

 (defun org-macro-expand (macro templates)

@@ -327,14 +327,20 @@ Return a list of arguments, as strings.  This is the opposite of

   "Initialize `org-macro--counter-table'."

   (setq org-macro--counter-table (make-hash-table :test #'equal)))

 

-(defun org-macro--counter-increment (name &optional reset)

+(defun org-macro--counter-increment (name &optional reset hold)

   "Increment counter NAME.

-NAME is a string identifying the counter.  When non-nil, optional

-argument RESET is a string.  If it represents an integer, set the

-counter to this number.  Any other non-empty string resets the

-counter to 1."

+NAME is a string identifying the counter.

+

+When non-nil, optional argument RESET is a string.  If it represents

+an integer, set the counter to this number.  Any other non-empty

+string resets the counter to 1.

+

+When non-nil, optional argument HOLD is a string.  If it is a

+non-empty string, keep the NAME counter at its previous value."

   (puthash name

-   (cond ((not (org-string-nw-p reset))

+   (cond ((org-string-nw-p hold)

+  (gethash name org-macro--counter-table 0))

+ ((not (org-string-nw-p reset))

   (1+ (gethash name org-macro--counter-table 0)))

  ((string-match-p "\\`[ \t]*[0-9]+[ \t]*\\'" reset)

   (string-to-number reset))

I haven't yet created a proper formatted patch, because I don't know if this is the best implementation. Would it be better to rename the RESET option to something more generic, like ARG? That way,

- If ARG is a "-" string, the counter value will be held and not incremented. 

- If ARG is a number represented as a string, it set the NAME counter to that value (like now).

- Else if ARG is a non-empty string, it resets the NAME counter to 1 (like now).

--

Kaushal Modi