Wishlist: Sweave: allow line breaks after forward slashes (PR#9444)

On 1/16/2007 5:26 AM, Arne Henningsen wrote:

[...]
Is there any reason for deparse() to add spaces around "+", "-", and "*"
operators but not around "/" operators?
R> deparse(parse( text = "a+b-c*d/e" ))
[1] "expression(a + b - c * d/e)"

I don't know, but it has been like that for the complete history of the
source code in the repository (almost 10 years).  I suppose someone thought

  a + b - c * d /
  e

would look ugly (even though they were happy to put one of the other
operators at the end of the line).  

This makes me quite reluctant to 
change it:  people get upset about changes to the look of their old
scripts, because they trigger spurious check errors.

Duncan Murdoch

The fact that it isn't the one you want doesn't mean it needs
to be listed as an outstanding issue in the bug reporting system.

Okay. Where can I list "minor" wishes?

On your to-do list?

Yes, that's a good idea!
This is my patch of /src/main/names.c:

--- names.c.orig        2007-01-16 11:03:24.000000000 +0100
+++ names.c     2007-01-16 10:30:43.000000000 +0100
@@ -149,7 +149,7 @@
 {"+",   do_arith, PLUSOP, 1, 2, {PP_BINARY,  PREC_SUM,    0}},
 {"-",   do_arith, MINUSOP,1, 2, {PP_BINARY,  PREC_SUM,    0}},
 {"*",   do_arith, TIMESOP,1, 2, {PP_BINARY,  PREC_PROD,   0}},
-{"/",   do_arith, DIVOP,  1, 2, {PP_BINARY2, PREC_PROD,   0}},
+{"/",   do_arith, DIVOP,  1, 2, {PP_BINARY,  PREC_PROD,   0}},
 {"^",   do_arith, POWOP,  1, 2, {PP_BINARY2, PREC_POWER,  1}},
 {"%%",  do_arith, MODOP,  1, 2, {PP_BINARY2, PREC_PERCENT,0}},
 {"%/%", do_arith, IDIVOP, 1, 2, {PP_BINARY2, PREC_PERCENT,0}},

(I have removed some blanks so that each line fits in a single line)

Now I get:
R> deparse(parse( text = "a+b-c*d/e" ))
[1] "expression(a + b - c * d / e)"

Does this patch has any negative side effects?

"make check" fails, but AFAIK this is just because of different positions
of line breaks:
[...]
running code in 'reg-tests-2.R' ... OK
comparing 'reg-tests-2.Rout'
to './reg-tests-2.Rout.save' ...3639,3640c3639,3640
< aov(formula = dep.variable ~ f1 * f2 + Error(subject / (f1 +
<     f2)), data = sample.df)
---

aov(formula = dep.variable ~ f1 * f2 + Error(subject/(f1 + f2)),
    data = sample.df)

3693,3694c3693,3694
< aov(formula = dep.variable ~ f1 * f2 + Error(subject / (f2 +
<     f1)), data = sample.df)
---

aov(formula = dep.variable ~ f1 * f2 + Error(subject/(f2 + f1)),
    data = sample.df)

make[3]: *** [reg-tests-2.Rout] Fehler 1
[...]

Duncan Murdoch

Thank you for all your hints,
Arne