Re: Re: Programming style: postfix/prefix vs. functional

*To*: mathgroup at smc.vnet.net*Subject*: [mg70704] Re: [mg70633] Re: [mg70587] Programming style: postfix/prefix vs. functional*From*: Andrzej Kozlowski <akoz at mimuw.edu.pl>*Date*: Mon, 23 Oct 2006 05:45:05 -0400 (EDT)*References*: <200610200921.FAA11092@smc.vnet.net> <200610210914.FAA29189@smc.vnet.net> <2A8E209D-C4D9-45C1-933B-5E3D955D99C5@mimuw.edu.pl> <acbec1a40610210543k3a861eb7tb3bdb777170618b@mail.gmail.com> <2F11E8C9-D5C5-45EC-BA91-7F52E72CCC3B@mimuw.edu.pl> <acbec1a40610220224h4d154c37rd6b0d909820cfd19@mail.gmail.com>

It seems to me you are making to much of this "correspondence". Why does it matter whether something "corresponds" to a "function applied at some particular level" or is "just a shorthand" for some particular expression? In fact, I think this is what "parsing" is about: the "parser" reads your input and converts it (without evaluation) to another form which is semantically equivalent . (There is a subtle difference between this and "formatting", which affects only the visual output). Andrzej Kozlowski On 22 Oct 2006, at 18:24, Chris Chiasson wrote: > On 10/21/06, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote: >> Well, I would say that f@x is just a "shorthand" for f[x] and does >> not "correspond" to any function. It seems to me that same applies to >> @@ and to @@@ ... > > But we know that @@ and @@@ correspond to Apply at level specification > {0} and {1}, respectively. We also know that /@ and //@ correspond to > Map at level specification {1} and {0,Infinity} (or just MapAll). It > seems to me that @ is the odd one out, because it doesn't "correspond > to a particular function". > > On 10/21/06, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote: >> (tm) Pro* >> Well, I would say that f@x is just a "shorthand" for f[x] and does >> not "correspond" to any function. It seems to me that same applies to >> @@ and to @@@ and none of these cases ? will yield any information. >> In fact, ? itself works in a curious way. Sometimes it corresponds to >> the function Information; as in >> >> Information[Sin] >> >> which is the same as ?Sin. But in some cases, notably ?@ you can't >> use Information; this >> Information[@] does not parse correctly (I think this is the right >> way to use "parse" ;-)), in other words, it is not syntactically >> correct. So ? seems actually work in two different ways: as another >> way to input Information but also rather like the symbol ! in front >> of a file name, which displays the contents of the file on the screen >> and does not correspond to any Mathematica function. >> >> Andrzej Kozlowski >> >> >> On 21 Oct 2006, at 21:43, Chris Chiasson wrote: >> >> > Andrzej Kozlowski, >> > >> > Thanks for the wildcard info! >> > >> > So, does @ correspond to Operate? I think Operate is a bit >> different >> > than @, but I am not sure. >> > >> > On 10/21/06, Andrzej Kozlowski <akoz at mimuw.edu.pl> wrote: >> >> (tm) Pro* >> >> >> >> On 21 Oct 2006, at 18:14, Chris Chiasson wrote: >> >> >> >> > One thing I have wondered is, what function corresponds to the >> >> short >> >> > hand "@". I know @ appears in Operate. Also, the ? can sometimes >> >> tell >> >> > what function an operator represents (try ?/@ ) , but ?@ only >> gives >> >> > System`$ (the symbol $ in the context System). >> >> >> >> That's because the symbol @ already has another meaning as a "wild >> >> card": >> >> >> >> @ , one or more characters excluding upperâ??case letters >> >> >> >> (A more general wild card is, of course *). So ?@ returns all the >> >> symbols defined in the contexts of the current session that >> do not >> >> contain capital letters. Evaluate some symbols whose names contain >> >> only small letter in Mathematica and try ?@ again to see this in >> >> action. >> >> >> >> Andrzej Kozlowski >> >> >> >> >> >> > >> >> > >> >> > On 10/20/06, Will Robertson <wspr81 at gmail.com> wrote: >> >> >> Hello, >> >> >> >> >> >> As a newcomer to Mathematica, I'm a little unsure on what "good >> >> >> style" >> >> >> would be in this programming language. I notice that several >> >> >> functions >> >> >> have prefix and postfix notations such as //. for >> >> ReplaceRepeated, /@ >> >> >> for Map, and so on. >> >> >> >> >> >> Clearly using these forms makes the code more compact, but >> >> sacrifices >> >> >> some level of readability. Are there guidelines or suggestions >> >> that >> >> >> have built up over the years of whether these are "good" or >> >> "bad" to >> >> >> use? >> >> >> >> >> >> If it's simply personal preference, what do you like to use? >> >> >> -- >> >> >> Many thanks, >> >> >> Will Robertson >> >> >> >> >> >> >> >> > >> >> > >> >> > -- >> >> > http://chris.chiasson.name/ >> >> > >> >> >> >> >> > >> > >> > -- >> > http://chris.chiasson.name/ >> >> > > > -- > http://chris.chiasson.name/

**References**:**Programming style: postfix/prefix vs. functional***From:*"Will Robertson" <wspr81@gmail.com>

**Re: Programming style: postfix/prefix vs. functional***From:*"Chris Chiasson" <chris@chiasson.name>