On 04/05/2022 08:28, Rasmus Villemoes wrote:
On 27/04/2022 19.21, Bernhard Voelker wrote:
On 4/27/22 16:14, Pádraig Brady wrote:
On 27/04/2022 11:07, Rasmus Villemoes wrote:
Though for interactive use, the new option is a benefit.
Given the interactive benefit and a previous request to add this functionality¹
I'm tentatively leaning towards adding this.
Re. the patch:
the implementation is quite clean in 2 places - the LONGINT_OK and the MPZ case
- and
doesn't seem to get into the way of any future extensions (null-separated
output, whatever).
Therefore, I'm also 70:30 for adding it.
Of course, we'd also need a long option and texinfo documentation.
Thanks. I don't care much about what the short option is, but it's quite
important for my use case that it does have a short form. Given the
NetBSD precedent [1], I think -h is fine. We can make the long option
--human-readable or --exponents, I don't have any opinion on that.
Should I respin with -h instead of -e?
I'll apply the attached later.
thanks again,
Pádraig
From f83b1e7b1c6d2a2c0211cc1097dc165a1918d8f3 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <rasmus.villem...@prevas.dk>
Date: Wed, 27 Apr 2022 12:07:20 +0200
Subject: [PATCH] factor: --exponents: new option for printing in x^y format
When factoring numbers that have a large 2^n factor, it can be hard to
eyeball just how many 2's there are. Add an option to print each prime
power factor in the x^y format (omitting the exponent when it is 1).
* src/factor.c: Add --exponents option for printing in x^y format.
* doc/coreutils.texi (factor invocation): Document the new option.
* tests/factor/create-test.sh: Add logic for passing options to factor.
* tests/factor/create-test.sh: Add test case for `factor -h`.
* tests/factor/run.sh: Honour options passed from the test case.
* tests/local.mk (factor_tests): Add tf37.sh.
* THANKS.in: Add previous suggester
(https://lists.gnu.org/r/coreutils/2017-11/msg00015.html)
Suggested-by: Emanuel Landeholm <emanuel.landeh...@gmail.com>
Signed-off-by: Rasmus Villemoes <rasmus.villem...@prevas.dk>
---
NEWS | 5 +++++
THANKS.in | 1 +
doc/coreutils.texi | 13 ++++++++++---
src/factor.c | 30 ++++++++++++++++++++++++++----
tests/factor/create-test.sh | 2 ++
tests/factor/run.sh | 3 ++-
tests/local.mk | 2 +-
7 files changed, 47 insertions(+), 9 deletions(-)
diff --git a/NEWS b/NEWS
index 3a9148637..16984003c 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,11 @@ GNU coreutils NEWS -*- outline -*-
long been documented to be platform-dependent.
[bug introduced 1999-05-02 and only partly fixed in coreutils-8.14]
+** New Features
+
+ factor now accepts the --exponents (-h) option to print factors
+ in the form p^e, rather than repeating the prime p, e times.
+
* Noteworthy changes in release 9.1 (2022-04-15) [stable]
diff --git a/THANKS.in b/THANKS.in
index 311196a04..c67a64b88 100644
--- a/THANKS.in
+++ b/THANKS.in
@@ -188,6 +188,7 @@ Eivind eivi...@multinet.no
Elbert Pol elbert....@gmail.com
Eldon Stegall el...@eldondev.com
Eli Zaretskii e...@is.elta.co.il
+Emanuel Landeholm emanuel.landeh...@gmail.com
Emile LeBlanc lebl...@math.toronto.edu
Emmanuel Lacour elac...@home-dn.net
Eric Backus er...@lsid.hp.com
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index b1ec7c61c..586ae7b34 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -18622,16 +18622,23 @@ These programs do numerically-related operations.
@command{factor} prints prime factors. Synopses:
@example
-factor [@var{number}]@dots{}
-factor @var{option}
+factor [@var{option}]@dots{} [@var{number}]@dots{}
@end example
If no @var{number} is specified on the command line, @command{factor} reads
numbers from standard input, delimited by newlines, tabs, or spaces.
-The @command{factor} command supports only a small number of options:
+The @command{factor} command supports supports the following options:
@table @samp
+@item -h
+@itemx --exponents
+@opindex -h
+@opindex --exponents
+print factors in the form @math{p^e}, rather than repeating
+the prime @samp{p}, @samp{e} times. If the exponent @samp{e} is 1,
+then it is omitted.
+
@item --help
Print a short help on standard output, then exit without further
processing.
diff --git a/src/factor.c b/src/factor.c
index 66ce28b84..83eda47d9 100644
--- a/src/factor.c
+++ b/src/factor.c
@@ -226,12 +226,16 @@ enum
static struct option const long_options[] =
{
+ {"exponents", no_argument, NULL, 'h'},
{"-debug", no_argument, NULL, DEV_DEBUG_OPTION},
{GETOPT_HELP_OPTION_DECL},
{GETOPT_VERSION_OPTION_DECL},
{NULL, 0, NULL, 0}
};
+/* If true, use p^e output format. */
+static bool print_exponents;
+
struct factors
{
uintmax_t plarge[2]; /* Can have a single large factor */
@@ -2457,6 +2461,12 @@ print_factors_single (uintmax_t t1, uintmax_t t0)
{
lbuf_putc (' ');
print_uintmaxes (0, factors.p[j]);
+ if (print_exponents && factors.e[j] > 1)
+ {
+ lbuf_putc ('^');
+ lbuf_putint (factors.e[j], 0);
+ break;
+ }
}
if (factors.plarge[1])
@@ -2525,6 +2535,11 @@ print_factors (char const *input)
{
putchar (' ');
mpz_out_str (stdout, 10, factors.p[j]);
+ if (print_exponents && factors.e[j] > 1)
+ {
+ printf ("^%lu", factors.e[j]);
+ break;
+ }
}
mp_factor_clear (&factors);
@@ -2542,15 +2557,18 @@ usage (int status)
else
{
printf (_("\
-Usage: %s [NUMBER]...\n\
- or: %s OPTION\n\
+Usage: %s [OPTION] [NUMBER]...\n\
"),
- program_name, program_name);
+ program_name);
fputs (_("\
Print the prime factors of each specified integer NUMBER. If none\n\
are specified on the command line, read them from standard input.\n\
\n\
"), stdout);
+ fputs ("\
+ -h, --exponents print factors in the form p^e\n\
+ rather than repeating the prime p, e times.\n\
+", stdout);
fputs (HELP_OPTION_DESCRIPTION, stdout);
fputs (VERSION_OPTION_DESCRIPTION, stdout);
emit_ancillary_info (PROGRAM_NAME);
@@ -2593,10 +2611,14 @@ main (int argc, char **argv)
atexit (lbuf_flush);
int c;
- while ((c = getopt_long (argc, argv, "", long_options, NULL)) != -1)
+ while ((c = getopt_long (argc, argv, "h", long_options, NULL)) != -1)
{
switch (c)
{
+ case 'h': /* NetBSD used -h for this functionality first. */
+ print_exponents = true;
+ break;
+
case DEV_DEBUG_OPTION:
dev_debug = true;
break;
diff --git a/tests/factor/create-test.sh b/tests/factor/create-test.sh
index be8248792..9c7d20422 100755
--- a/tests/factor/create-test.sh
+++ b/tests/factor/create-test.sh
@@ -66,6 +66,7 @@ case $t in
t34) set ${q}956336 ${q}958335 d1ae6bc712d994f35edf55c785d71ddf31f16535 ;;
t35) set ${q}958336 ${q}960335 2374919a89196e1fce93adfe779cb4664556d4b6 ;;
t36) set ${q}960336 ${q}962335 569e4363e8d9e8830a187d9ab27365eef08abde1 ;;
+ t37) set -- 0 10000000 8c4d3f021ac89fa0f7ce21857e16474549f83417 -h ;;
*)
echo "$0: error: unknown test: '$test_name' -> '$t'" >&2
exit 1
@@ -80,4 +81,5 @@ exec sed \
-e "s/__START__/$1/" \
-e "s/__END__/$2/" \
-e "s/__CKSUM__/$3/" \
+ -e "s/__OPTS__/$4/" \
-e "s!__TEMPLATE__!$TEMPLATE!" "$template"
diff --git a/tests/factor/run.sh b/tests/factor/run.sh
index 4a1dbb01b..a95e9b6d3 100755
--- a/tests/factor/run.sh
+++ b/tests/factor/run.sh
@@ -23,12 +23,13 @@ print_ver_ factor seq sha1sum
START=__START__
END=__END__
CKSUM=__CKSUM__
+ OPTS=__OPTS__
test "$START" = '__ST''ART__' && skip_ 'ignoring factor test template'
echo "$CKSUM -" > exp
f=1
-seq $START $END | factor | sha1sum -c --status exp && f=0
+seq $START $END | factor $OPTS | sha1sum -c --status exp && f=0
Exit $f
diff --git a/tests/local.mk b/tests/local.mk
index 0f7778619..ff919bfc5 100644
--- a/tests/local.mk
+++ b/tests/local.mk
@@ -739,7 +739,7 @@ factor_tests = \
$(tf)/t20.sh $(tf)/t21.sh $(tf)/t22.sh $(tf)/t23.sh $(tf)/t24.sh \
$(tf)/t25.sh $(tf)/t26.sh $(tf)/t27.sh $(tf)/t28.sh $(tf)/t29.sh \
$(tf)/t30.sh $(tf)/t31.sh $(tf)/t32.sh $(tf)/t33.sh $(tf)/t34.sh \
- $(tf)/t35.sh $(tf)/t36.sh
+ $(tf)/t35.sh $(tf)/t36.sh $(tf)/t37.sh
$(factor_tests): $(tf)/run.sh $(tf)/create-test.sh
$(AM_V_GEN)$(MKDIR_P) $(tf)
--
2.26.2
