#+TITLE: Ypot's
#+NICK: Ypot
#+AVATAR: https://github.com/Ypot.png
#+LINK: https://github.com/Ypot/
#+FOLLOW: Omar https://www.matem.unam.mx/~omar/social.org
#+FOLLOW: Andros https://host.org-social.org/andros/social.org

* Posts
** 2026-06-27T00:15:51+0200
:PROPERTIES:
:CLIENT: org-social.el
:LANG: en
:TAGS: emacs calc calc-embedded emacs-carnival
:END:
*** How to read this post
- You could open it in Emacs (interactive): =M-x eww RET https://raw.githubusercontent.com/Ypot/social/refs/heads/main/org-social.org=. Optionally, you can do =M-x org-mode= (strongly recommended).
- Want to read this in Org Social? You can follow me: =#+FOLLOW: Ypot https://ypot.github.io/social/org-social.org=, and activate org-mode: =M-x org-mode= when reading the post (strongly recommended).
- Just want it rendered in a browser? https://github.com/Ypot/social/blob/main/org-social.org (not interactive, not recommended).

*** Intro
*Calc Embedded* operates inside any ordinary buffer. There is no calc buffer in sight, there is no major, nor minor mode: *Each formula is its own little calculator.*

If you are reading this in an Emacs buffer, try it without leaving this spot: put point on the formula between =$= signs and press =C-x * u=:
$80 km/h * 2h$

Maybe you will need this first:
#+begin_src emacs-lisp
(setq calc-multiplication-has-precedence nil)
#+end_src

Try again:
$80 km/h * 2h$

*** Evaluates-to formulas
Add ~=>~ and it evaluates-to the right side, keeping both sides. Either way the units ride along and cancel where they can. Put point again on the formula between =$= signs and press =C-x * u=:
$(1000 kg/m^3) * (2 m^3) => $

*** Assignment formulas
Add ~:=~ and it assigns a value to a variable that the rest of the buffer can reuse.

=M-1 C-x * a= detects and re-activates every "assignment-formula" in the buffer (the =M-1= forces a clean rebuild). Then, you just have to put the point on the last "evaluates-to formula" and press =C-x * u=:
$rate := 45 EUR/h$
$hours := 32 h$
$rate * hours => $

*** Units
Units handling is brilliant in Calc, and we can leverage it in Calc Embedded:
$leg1 := 3 m$
$leg2 := 40 cm$
$hyp := sqrt(leg1^2 + leg2^2) => $

The bare version keeps =m= and =cm= apart — it returns =sqrt(9 m^2 + 1600 cm^2)=, unconverted. Wrap it in =usimplify= and Calc reconciles the scales into one clean length:
$hyp := usimplify(sqrt(leg1^2 + leg2^2)) => $

$mass := 2 kg$
$v := 3 m/s$
$E_c := (1/2) mass * v^2 => $

Out comes =9 kg m^2 / s^2=

*** Equations
It can also solve equations! Press =C-x * u= on the next formula:
$solve(22 x + 33 = 65, x) => $

*** Batch
With several formulas at once you do not poke them one by one; =M-1 C-x * u= should compute them all [fn:1893e64a74b69123].

$rate := 45 EUR/h$
$hours := 32 h$
$material := 180 EUR$
$rate * hours => $

$subtotal := rate * hours + material => $
Total w/VAT:  $subtotal * 1.21 => $

*** Finale: make it big
Embedded mode can also draw formulas in two dimensions — stacked fractions, raised exponents, roots — with the Big language. A global-mode line sets the display for the whole buffer; Calc scans for it from the top of the buffer, so where you place it does not matter:
[calc-global-mode: language: nil]
Change that =nil= to =big=, re-scan with =C-x * a=, then recompute with =M-1 C-x * u=: every formula in the post redraws stacked. A 2-D formula spans several lines, so it will break.

*** Bonus: base conversion
[calc-mode: radix: 2]

16#A3

[calc-mode: radix: 6]

16#A3

[calc-mode: radix: 10]

16#A3

*** Footnotes
[fn:1893e64a74b69123] Thanks to Eli Zaretskii for solving it for Emacs 31 ([[https://debbugs.gnu.org/cgi/bugreport.cgi?bug=80901][Emacs bug#80901]]). On Emacs 30.x and earlier you may need this workaround:
#+begin_src emacs-lisp
(defun calc-embedded-update-all-formulas ()
  "Update all Calc embedded formulas in the current buffer.
Processes in dependency order: := assignments, then => evaluations,
then bare expressions (variable references like $var$).
Workaround for a bug where the prefix-arg path of
`calc-embedded-update-formula' silently drops formulas during
cascade recomputation (Emacs bug#80901)."
  (interactive)
  (let (assignments evaltos expressions (count 0))
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward "\\$\\([^$\n]+\\)\\$" nil t)
        (let ((text (match-string 1))
              (pos (copy-marker (1+ (match-beginning 0)))))
          (cond
           ((and (string-match ":=" text) (not (string-match "=>" text)))
            (push pos assignments))
           ((string-match "=>" text)
            (push pos evaltos))
           (t
            (push pos expressions))))))
    (setq assignments (nreverse assignments)
          evaltos (nreverse evaltos)
          expressions (nreverse expressions))
    (save-excursion
      (dolist (pos (append assignments evaltos expressions))
        (goto-char pos)
        (condition-case nil
            (progn (calc-embedded-update-formula nil)
                   (cl-incf count))
          (error nil))
        (set-marker pos nil)))
    (message "Updated %d formulas" count)))

(advice-add 'calc-embedded-update-formula :around
            (lambda (orig arg)
              "Redirect prefix-arg path to the workaround for bug#80901."
              (if arg
                  (calc-embedded-update-all-formulas)
                (funcall orig arg))))
#+end_src

** 2026-07-07T21:09:51+0200
:PROPERTIES:
:ID: 2026-07-07T21:10:29+0200
:LANG: en
:CLIENT: org-social.el
:TAGS: pmp projectmanagement android beta
:MOOD: 🛠️
:END:
Been building a little tycoon game on the side (you run a project company, take on jobs, and try to keep the budget and the deadlines under control).
Built for the 2026 PMP exam if you're chasing the cert; just an attempt at a fun sim if you're not.

Why it might be your kind of thing:
- *A real management sim* — not a quiz wearing a game costume.
- *No ads, no tracking, no phone-home.* Your data never leaves the device.
- One-person, nights-and-weekends project.

It's in a closed beta on Google Play. If you are willing to try it for a couple of weeks (Google's beta rules) you'd really help me out — and as a thank-you, everyone who tests during the beta keeps the full version free, for good.    

To try it: first join the group: https://groups.google.com/g/pm-tycoon-testers
Then install: https://play.google.com/store/apps/details?id=app.pmtycoon

One Google account, start to finish. The beta is tied to the Google account your phone uses for the Play Store (check it: Play Store → your profile picture). Join the group and install with that same account.
If the group opens the wrong account (common with several accounts), open the link in a private/incognito window and sign in with the right one — clean session, no mix-ups.
Still stuck? Email me and I'll add you directly.