Yet another literate programming application

Yet another literate programming application

[Alan Schmitt]

Or rather, I should say a literate algebra and calculating application:
http://calca.io/

I'd really like to be able to call such an engine from org-mode. (And
I'm secretly hoping something will say that $some_programming_language
already does it and is fully integrating with org.)

Alan

Re: Yet another literate programming application

[Eric Schulte]

Alan Schmitt <alan.schmitt@polytechnique.org> writes:

> Or rather, I should say a literate algebra and calculating application:
> http://calca.io/
>

If this is appealing, it may be worth checking out the "Embedded Mode"
of Emacs calc [1].  From what I can tell on the calc.io website, Emacs
calc provides the same functionality, but Emacs calc has the benefits of
(1) it is open source meaning you can confirm calculations and your
answers (in my opinion a must for any peer reviewed publication), and
(2) it may be embedded in *any* type of file.

>
> I'd really like to be able to call such an engine from org-mode. (And
> I'm secretly hoping something will say that $some_programming_language
> already does it and is fully integrating with org.)
>

Yes, you can use calc embedded mode in Org-mode files as well.

>
> Alan
>

Cheers,

Footnotes: 
[1]  (info "(calc)Embedded Mode")

-- 
Eric Schulte
http://cs.unm.edu/~eschulte

Re: Yet another literate programming application

[Alan Schmitt]

schulte.eric@gmail.com writes:

> Alan Schmitt <alan.schmitt@polytechnique.org> writes:
>
>> Or rather, I should say a literate algebra and calculating application:
>> http://calca.io/
>>
>
> If this is appealing, it may be worth checking out the "Embedded Mode"
> of Emacs calc [1].  From what I can tell on the calc.io website, Emacs
> calc provides the same functionality, but Emacs calc has the benefits of
> (1) it is open source meaning you can confirm calculations and your
> answers (in my opinion a must for any peer reviewed publication), and
> (2) it may be embedded in *any* type of file.

Embedded calc mode is amazing, thanks for the link! It does not seem as
intuitive to work with equations (I've tried doing the Functions and
Solving Equations examples in calc), and there are funny results with
spaces in names. If someone knows how to do the even/odd example in
calc, please let me know. Here is what I got so far:

* Variables

#+BEGIN_SRC calc

m := 42

b := 1000

m x + b => 42 x + 1000

mass of earth := 5.972e24 kg

mass of moon := 7.34767309e22 kg

mass of earth / (mass of moon) => earth / moon

#+END_SRC

* Functions

#+BEGIN_SRC calc

eq := f = 1.8 c + 32

ceq := solve(eq, c) => c = f / 1.8 - 17.7777777778

subst(eq, c, 20) => f = 68.

subst(ceq, f, 100) => c = 37.7777777778

even(n) := n = 0 ? true : odd(n - 1)

odd(n) := n = 1 ? true : even(n - 1)

#+END_SRC

Thanks again for pointing me to how great calc can be,

Alan

Re: Yet another literate programming application

[Eric Schulte]

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Alan Schmitt <alan.schmitt@polytechnique.org> writes:

> schulte.eric@gmail.com writes:
>
>> Alan Schmitt <alan.schmitt@polytechnique.org> writes:
>>
>>> Or rather, I should say a literate algebra and calculating application:
>>> http://calca.io/
>>>
>>
>> If this is appealing, it may be worth checking out the "Embedded Mode"
>> of Emacs calc [1].  From what I can tell on the calc.io website, Emacs
>> calc provides the same functionality, but Emacs calc has the benefits of
>> (1) it is open source meaning you can confirm calculations and your
>> answers (in my opinion a must for any peer reviewed publication), and
>> (2) it may be embedded in *any* type of file.
>
> Embedded calc mode is amazing, thanks for the link! It does not seem as
> intuitive to work with equations (I've tried doing the Functions and
> Solving Equations examples in calc),

Very cool, thanks for sharing.  I would note, that one nice thing about
embedded mode is that there is no need for the #+begin/end_src calc
blocks, rather the formulas may be placed directly in the Org-mode file.
So to re-write a small portion of your previous example...


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
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#+Title: Emacs Calc Embedded Mode Examples

* Temperature Conversion (solving equations)
Conversion from Celsius to Fahrenheit involves multiplication by 1.8
and the addition of 32 as shown below.

eq := f = 1.8 c + 32

Solving for Celsius from Fahrenheit is then.

ceq := solve(eq, c) =>

So, if we know that water boils at 100\deg Celsius, we can find the
boiling point of water in Fahrenheit.

subst(eq, c, 100) =>

Or if we know that paper burns at 451\deg Fahrenheit, we can find the
burning point of paper in Celsius.

subst(ceq, f, 451) =>

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Using embedded mode is still fairly awkward for me.  I would benefit
greatly from some sort of quick reference card explaining the key
bindings and maybe an easier way to switch to/from embedded mode.

> and there are funny results with spaces in names. If someone knows how
> to do the even/odd example in calc, please let me know. Here is what I
> got so far:
>

I'm not clear on how the even/odd example works in calc, could you share
a link to the specific manual page you're referencing?  I've long felt
that calc would be a *very* powerful tool, if only I could climb the
learning curve.

Thanks,

-- 
Eric Schulte
http://cs.unm.edu/~eschulte

Re: Yet another literate programming application

[Alan Schmitt]

schulte.eric@gmail.com writes:

> Very cool, thanks for sharing.  I would note, that one nice thing about
> embedded mode is that there is no need for the #+begin/end_src calc
> blocks, rather the formulas may be placed directly in the Org-mode
> file.

Yes, but I was thinking of exporting the result to something nice, so I
wanted to tell org I was in calc mode. In fact, I'm not sure to like how
calc deals with delimiters: it's not liking the "#+..." if there is no
blank line. I know it's configurable, though.

> Using embedded mode is still fairly awkward for me.  I would benefit
> greatly from some sort of quick reference card explaining the key
> bindings and maybe an easier way to switch to/from embedded mode.

Yes, I basically read through the info page. The useful shortcuts I
picked were:

- C-x * u: update the formula (it's almost C-x * e C-x * e, except it
  will still work if another formula is currently in embedded mode)
- C-x * d: duplicate the formula and enter embedded calc mode
- s = in calc mode: add the nice => thingy

> I'm not clear on how the even/odd example works in calc, could you share
> a link to the specific manual page you're referencing?  I've long felt
> that calc would be a *very* powerful tool, if only I could climb the
> learning curve.

Well, it does not work as such. I don't know how to define mutually
recursive functions in calc, and that was basically my question. (But
then one may then use a real programming language at that point.) The
manual never really defines functions, and it seems that what I want to
do is rewrite things, but I cannot find a way to do it correctly.

Alan