It is important for the students to understand that there is a difference between "_" and "-" and also that " " can be important.
"_" is put immediately to the left of the number intentionally and the same goes with "." and ":" When the signs are close together and not separated by " " they can have a different meaning. "." is frequently used to change the meaning of another sign standing next to it but it also has a meaning on its own. Same goes with "_". The whole idea of J to use sign combination without " " between them is fundamental so the students must understand the importance of " ". It is good to use ";:" to box the operations and show how they differ. ;:' + ---- ___ 1 -3 ___4' 2007/3/2, Steven Phillips <[EMAIL PROTECTED]>:
The space between _ and 1 was intentional (and actually the source of a problem for one student). For an experienced J person (like yourself) the intended meaning and way to express it are obvious. But to a novice, and particularly one from the "pen and paper" tradition, the significance of whitespace may not be the first thing that draws their attention. It may not even draw their attention at all. This example is not a criticism of the language. (For me, the highly systematic design of the language is one of its main attractions.) Rather, it is a reflection on a source of difficulty students have with learning the language, which I expect applies generally. Steve Björn Helgason wrote: > Possibly a typo > > First is a space between the _ and 1 > *: _1 > _ 1 > > Second *: is square > > *: _1 > 1 > > %: is square root > > %: _1 > 0j1 > > > 2007/3/1, Steven Phillips <[EMAIL PROTECTED]>: >> >> I am teaching J to non-native English speakers (Japanese university >> students) >> as part of an optional Technical English course for engineering >> students. >> The main objective of the course is to gain experience at listening >> to and >> presenting in English. The topic could be anything, but I use J >> because it >> allows you to do computations with little fuss and in >> a radically different way than a procedural approach. >> >> Response to the J part of the course has been mixed, keeping in mind the >> wide range of abilities in both English and programming. On the positive >> side, >> students get an insight-like (aha!) feeling of discovery when they >> can see >> the meaning behind the symbols. However, getting to this point requires >> breaking some long-held assumptions over what the symbols mean >> (e.g., confusing the use of "-" versus "_"; or "_1" versus "_ 1"). It >> may >> seem obvious to an experienced J person and hence hardly worth more >> than a passing remark, but these are the sorts of things that can really >> block progress when attention is drawn to a more complex expression. For >> example, students can get stuck on even the simplest expressions like >> *: _ 1 >> _ 1 >> which looks like a bug - square of negative 1 is negative 1. In trying >> to work out what went wrong, a student may tend to focus of the part >> that is not immediately obvious (*:) and fail to question the more >> basic assumption that _ 1 means negative one. Casual experimentation >> can even reinforce the false assumption that space is not significant: >> -1 >> _1 >> - 1 >> _1 >> _1 >> _1 >> _ 1 >> _ 1 >> >> Steve >> >> ---------------------------------------------------------- >> Steven Phillips, PhD >> Cognitive and Behavioral Sciences Group, >> Neuroscience Research Institute, AIST >> 1-1-1 Umezono, Tsukuba Central 2, Tsukuba, Ibaraki 305-8568 Japan >> Tel: +81 29 861 5165 (PHS: 45165) Fax: +81 29 861 5857 >> WWW: <http://staff.aist.go.jp/steven.phillips> >> ---------------------------------------------------------- >> >> >> >> Steven H. Rogers wrote: >> > I'm doing an informal survey on the use of Array Programming Languages >> > for teaching. If you're using J in this manner I'd like to hear from >> > you. What subject was/is taught, academic level, results, lessons >> > learned, etc. >> > >> > Regards, >> > Steve >> > >> > ---------------------------------------------------------------------- >> > For information about J forums see http://www.jsoftware.com/forums.htm >> > >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > > > > ------------------------------------------------------------------------ > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
-- Björn Helgason, Verkfræðingur Fugl&Fiskur ehf, Þerneyjarsund 23, Box 127 801 Grímsnes ,t-póst: [EMAIL PROTECTED] Skype: gosiminn, gsm: +3546985532 Landslags og skrúðgarðagerð, gröfuþjónusta http://groups.google.com/group/J-Programming Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans góður kennari getur stigið á tær án þess að glansinn fari af skónum /|_ .-----------------------------------. ,' .\ / | Með léttri lund verður | ,--' _,' | Dagurinn í dag | / / | Enn betri en gærdagurinn | ( -. | `-----------------------------------' | ) | (\_ _/) (`-. '--.) (='.'=) `. )----' (")_(")
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