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Implement finite?' in core and fix R6RS finite?' and `infinite?'

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* libguile/numbers.c (scm_finite_p): Add new predicate `finite?' from
  R6RS to guile core, which returns #t if and only if its argument is
  neither infinite nor a NaN.  Note that this is not the same as (not
  (inf? x)) or (not (infinite? x)), since NaNs are neither finite nor
  infinite.

* test-suite/tests/numbers.test: Add test cases for `finite?'.

* module/rnrs/base.scm: Import `inf?' as `infinite?' instead of
  reimplementing it.  Previously, the R6RS implementation of
  `infinite?' did not detect non-real complex infinities, nor did it
  throw exceptions for non-numbers.  (Note that NaNs _are_ considered
  numbers by scheme, despite their name).

  Import `finite?' instead of reimplementing it.  Previously, the R6RS
  implementation of `finite?' returned #t for both NaNs and non-real
  complex infinities, in violation of R6RS.

* NEWS: Add NEWS entries, and reorganize existing numerics-related
  entries together under one subheading.

* doc/ref/api-data.texi (Real and Rational Numbers): Add docs for
  `finite?' and scm_finite_p.
This commit is contained in:
Mark H Weaver 2011-01-26 09:34:02 -05:00 • committed by Andy Wingo
commit 7112615f73
5 changed files with 89 additions and 13 deletions
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39
NEWS
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@ -10,18 +10,14 @@ latest prerelease, and a full NEWS corresponding to 1.8 -> 2.0.
Changes in 1.9.15 (since the 1.9.14 prerelease):
** Infinities are no longer integers.
** Changes and bugfixes in numerics code
*** Infinities are no longer integers.
Following the R6RS, infinities (+inf.0 and -inf.0) are no longer
considered to be integers.
** New reader option: `hungry-eol-escapes'
Guile's string syntax is more compatible with R6RS when the
`hungry-eol-escapes' option is enabled. See "String Syntax" in the
manual, for more information.
** `expt' and `integer-expt' changes when the base is 0
*** `expt' and `integer-expt' changes when the base is 0
While `(expt 0 0)' is still 1, and `(expt 0 N)' for N > 0 is still
zero, `(expt 0 N)' for N < 0 is now a NaN value, and likewise for
@ -29,6 +25,33 @@ integer-expt. This is more correct, and conforming to R6RS, but seems
to be incompatible with R5RS, which would return 0 for all non-zero
values of N.
*** New procedure: `finite?'
Add scm_finite_p `finite?' from R6RS to guile core, which returns #t
if and only if its argument is neither infinite nor a NaN. Note that
this is not the same as (not (inf? x)) or (not (infinite? x)), since
NaNs are neither finite nor infinite.
*** R6RS base library changes
**** `infinite?' changes
`infinite?' now returns #t for non-real complex infinities, and throws
exceptions for non-numbers. (Note that NaNs _are_ considered numbers
by scheme, despite their name).
**** `finite?' changes
`finite?' now returns #f for NaNs and non-real complex infinities, and
throws exceptions for non-numbers. (Note that NaNs _are_ considered
numbers by scheme, despite their name).
** New reader option: `hungry-eol-escapes'
Guile's string syntax is more compatible with R6RS when the
`hungry-eol-escapes' option is enabled. See "String Syntax" in the
manual, for more information.
** And of course, the usual collection of bugfixes
Interested users should see the ChangeLog for more information.