drawExpression package

Hello,

Excellent initiative. That is going to be very interesting too for 
complex stuff like loops and if() statements.

A couple of suggestions:
- In general, I would add corresponding R input and output just beneath 
the "visual" display of what happens, so that readers can try it in R 
and see what happens.

- P. 1, para. 1: ... have a common mode, one of character, logical, and 
numeric (to match the order of visual items).

- P. 3, para. 4: The character mode always wins. Logical always looses.

- P. 5, para. 11: A little sentence explaining nchar() would be useful. 
Something like: "Count the number of characters in each string:"

- P. 6, para. 14.1: again, a little explanation: "Matrices are filled by 
  columns by default :" ... "But you can change it :"

- P. 7, para. 14.2: "Matrices have two dimensions and you must provide 
extractors for each of them. You first extract the rows, then the columns."

- P. 9: you use merge() that creates a list, before introducing what a 
list is... This is confusing.

- P. 11, para. 16.1: you use regular expressions without introducing 
what it is. No R beginner that has not done serious programming knows 
what a "Regexp" is.

(P.S.: Juste apr?s avoir ?crit tout ceci, je me rend compte que tu 
travailles ? l'Universit? de Caen. Je suis pass? par l?: j'ai mis en 
place les nouvelles infrastructures d'?levage d'oursins ? la Station 
Marine de Luc-sur-mer il y a une quinzaine d'ann?es de cela.

Bon week-end,

Philippe Grosjean
..............................................<?}))><........
  ) ) ) ) )
( ( ( ( (    Prof. Philippe Grosjean
  ) ) ) ) )
( ( ( ( (    Numerical Ecology of Aquatic Systems
  ) ) ) ) )   Mons University, Belgium
( ( ( ( (
..............................................................

Hello all,

Following a discussion at the end of december [1] I created a package "drawExpression" on R-Forge. It is still in a very early stage! Here is a draft of a PDF "visual reference card" that show the usage of the code:

https://r-forge.r-project.org/plugins/scmsvn/viewcvs.php/pkg/visualRefCard/visualRefCard.pdf?rev=3&root=drawexpression&view=log

Advices welcome!
Best,
Sylvain

[1] https://stat.ethz.ch/pipermail/r-devel/2009-December/056170.html

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A couple of suggestions:
- In general, I would add corresponding R input and output just beneath the "visual" display of what happens, so that readers can try it in R and see what happens.

Yes, it lacks something like that. Perhaps a first line which copy the concrete code evaluated.

- P. 1, para. 1: ... have a common mode, one of character, logical, and numeric (to match the order of visual items).

- P. 3, para. 4: The character mode always wins. Logical always looses.

- P. 5, para. 11: A little sentence explaining nchar() would be useful. Something like: "Count the number of characters in each string:"

- P. 6, para. 14.1: again, a little explanation: "Matrices are filled by  columns by default :" ... "But you can change it :"

- P. 7, para. 14.2: "Matrices have two dimensions and you must provide extractors for each of them. You first extract the rows, then the columns."

Thanks! I have corrected all that.

- P. 9: you use merge() that creates a list, before introducing what a list is... This is confusing.

Well, it creates a data.frame I think, and data.frame aren't handled yet (they are seen as list)... I need a graphical convention for data.frame and for factor.

I'm wondering also how to represent functions that need a *symbol* as one of the arguments, for instance

- P. 11, para. 16.1: you use regular expressions without introducing what it is. No R beginner that has not done serious programming knows what a "Regexp" is.

Well, this is right, but there is a mix of different logics. At the beginning, it was supposed to include very few text, to stress general principles of the langage, and to be like a reference card for quickly checking the behavior of a method. For instance, which column names are preserved by cbind? The first matrix column names or the second? etc. But the document is becoming rather an introductory text.

(P.S.: Juste apr?s avoir ?crit tout ceci, je me rend compte que tu travailles ? l'Universit? de Caen. Je suis pass? par l?: j'ai mis en place les nouvelles infrastructures d'?levage d'oursins ? la Station Marine de Luc-sur-mer il y a une quinzaine d'ann?es de cela.

J'y fais de la linguistique de corpus, mais pr?cairement !

Regards,
Sylvain

--
Sylvain Loiseau
sylvain.loiseau at unicaen.fr

Universit? de Caen Basse Normandie
Maison de la Recherche en Sciences Humaines
MRSH - SH018
Esplanade de la Paix
Campus 1
14032 Caen Cedex