R6RS Errata

R6RS Errata
R6RS Errata
Revised
Report on the Algorithmic Language Scheme
§ 1.13
The description of the example program mentions
procedures
get-bytes-all
and
put-bytes
, which should be
get-bytevector-all
and
put-bytevector
The example code is missing a call to
close-port
, and should be:
#!r6rs
(import (rnrs base)
(rnrs io ports)
(rnrs programs))
(let ((p (standard-output-port)))
(put-bytevector p
(call-with-port
(open-file-input-port
(cadr (command-line)))
get-bytevector-all))
(close-port p))
§ 4
The term "read syntax" mentioned in the introduction of the
chapter should be "datum syntax".
§ 4.1
The sentence:
"Some non-terminal names refer to the Unicode scalar values of the same
name: (U+0009),
(U+000A), (U+000D), tabulation> (U+000B),

(U+000C),
(U+000D), (U+0020),
(U+0085), (U+2028),
and (U+2029)."
contains a duplicate " (U+000D)", which
should be elided.
§ 4.2.1
The rule
-> + .
is redundant.
In the production for ,
the two occurrences of should have a
* after them.
§ 4.2.1, § 4.2.8
The rules for suggest that the lexical syntax
for the external representations of number objects is case-sensitive,
with a number of specific exceptions, while the first
apragraph of § 4.2.8 claims that case is not significant
in external representations of number objects. This should be
resolved by making case generally insignificant in the
external representation of number objects.
§ 4.2.6
The sentence
"Case is significant in #\, and in
#\, but not in #\x#value>." is worded confusingly.
It should be
"Case is significant in #\, and in
#\, but not the in the #value> part of #\x."
§ 4.2.8
The following sentence should be added:
"The
-nan.0
literal also represents a NaN."
§: 5.10
The sentence
"An object fetched from a location, by a variable reference or by
a procedure such as
car
vector-ref
, or
string-ref
, is
equivalent in the sense of
eqv?
(section 11.5)
to the object last stored in the location before the
fetch."
should be amended by:
", except
when that object is a procedure. When the object is a procedure, the
object fetched from the location will also be a procedure that behaves
identically to the procedure last stored in the location, but it is
possible that it is not the same object."
§ 7.3
The
(stack)
example library is missing an
import of
(rnrs mutable-pairs)
§ 11.3
The description of the procedures is out of order and should
be:
"equal, monotonically increasing, monotonically nondecreasing,
monotonically decreasing, or monotonically nonincreasing"
There is an occurrence of the name
fl<
which
should be
fl§ 11.4.5
The first example for
case
is slightly
confusing, as it suggests that 1 is a composite number: It
should be elided from the second branch of the
case
§ 11.5
In the definition of the behavior of
eqv?
on
inexact numbers - both
#t
and
#f
cases - the phrase
" [...] as a finite composition of Scheme's standard arithmetic
procedures."
should be augmented by:
", as long as the evaluation of that application does not
involve NaN."
The following sentence should be elided:
"Furthermore, a constant may be copied at any time by the implementation so
as to exist simultaneously in different sets of locations, as noted in
section 11.4.1."
The following example for
eq?
(eq? car car) => #t
should be replaced by
(eq? car car) =>
unspecified
§ 11.6
In the entry for
list-ref
list-tail
" should be replaced by "
list-ref
".
§ 11.7.4
The two examples for
and
on infinities have extra parentheses.
The examples for
min
and
max
involving infinities should be prefixed by:
"For any real number object
that is not a
NaN
:"
The entries for
inexact
exact
min
, and
max
mention a condition
type
&implementation-violation
, which should
be
&implementation-restriction
The entry for
rationalize
says "returns a the a
number object": the "the" should be elided.
The respectively second templates for
and
should have parameter lists
... respectively.
The example:
(imag-part 1.1+2.2i) => 2.2i ; approximately
should be replaced by:
(imag-part 1.1+2.2i) => 2.2 ; approximately
In the description of the
div
mod
etc., the wording
"In each case,
must be neither infinite nor a NaN,
and
must be nonzero; otherwise, an exception with
condition type
&assertion
is raised."
should be replaced by:
"If
and
are exact,
must be nonzero. In the
cases where the mathematical requirements in section 11.7.3
cannot be satisfied by any number object, either an exception
is raised with condition type
&implementation-restriction
, or unspecified
number objects (one for for
div
mod
div0
and
mod0
, two for
div-and-mod
and
div0-and-mod0
) are
returned."
The example
(expt 0 5+.0000312i) => 0
should be replaced by:
(expt 0 5+.0000312i) => 0.0
The note for
string->number
should be replaced
by:
"If the arguments to
string->number
are a
string and a valid radix as specified, it must produce a
number object or
#f
; it may not raise an
exception."
(I.e.,
string->number
may raise an exception
if the argument is not a string.)
§ 11.9
The
append
procedure can be
called with zero arguments. Thus, in the description of
append
, a template
(append)
should be added.
The sentence at the end of the entry for
append
should be clarified to:
"The return value is made from new pairs for all arguments but the
last; the last is merely placed at the end of the new structure."
§ 11.17
Two of the examples involve calls to
sqrt
for
which Scheme implementations are allowed to return either exact
or inexact results, which makes the examples potentially
confusing.
§ 11.19
The wording for the second bullet for vector patterns says
"F is a vector of
or more elements", but should
say "F is a vector of
elements".
The last example in this section:
p => (15 5)
should be:
p => (15 . 5)
§ D
The example is missing the following line at the end:
(close-output-port (current-output-port))
Standard Libraries
§ 1.2
In the description of
string-titlecase
, the
words "via
char-titlecase
" should be removed.
(I.e.
string-titlecase
should use the full
mapping, not just the scalar-value-to-scalar-value mapping.)
The examples:
(string-titlecase "r6rs") => "R6Rs"
(string-titlecase "R6RS") > "R6Rs"
should be replaced by:
(string-titlecase "r6rs") => "R6rs"
(string-titlecase "R6RS") > "R6rs"
§ 2.4
The sentence
"The length of
bytevector
or,
respectively, of
list
must be divisible by
size
."
should be replaced by
"The length of
bytevector
must be divisible by
size
."
§ 2.6
In the entry for
bytevector-s32-native-set!
the interval for
should be {-2
31
..., 2
31
- 1} instead of {-2
31
, ...,
32
- 1}.
§ 2.7
In the entry for
bytevector-s64-native-set!
the interval for
should be {-2
63
..., 2
63
- 1} instead of {-2
63
, ...,
64
- 1}.
§ 2.9
In the entry for
utf16->string
utf32->string
, the argument
endianness-mandatory
should be spelled
endianness-mandatory?
The sentence in the specification of
utf16->string
Bytevector
is decoded according to UTF-16BE or
UTF-16LE:"
should be replaced by
Bytevector
is decoded according
to UTF-16, UTF-16BE, UTF-16LE, or a fourth encoding scheme that differs from
all three of those as follows:"
The sentence in the specification of
utf32->string
Bytevector
is decoded according to UTF-32BE or
UTF-32LE:"
should be replaced by
Bytevector
is decoded according
to UTF-32, UTF-32BE, UTF-32LE, or a fourth encoding scheme that differs from
all three of those as follows:"
§ 3
The example
(for-all even? '(3 1 4 1 5 9 . 2)) => #f
should be removed, as this call to
for-all
may
raise an exception.
§ 4
The example for the call to
vector-sort!
is
incorrect; it should be:
(define v (vector 3 5 2 1))
(vector-sort! < v) =>
unspecified
v => #(1 2 3 5)
§ 6.1
The sentence
"Each call to a record constructor returns a new record with a fresh
location [...]"
should be replaced by:
"Each call to a record constructor of a mutable record type
returns a new record with a fresh location [...]"
The sentence
If
obj
and
obj
are both records of the same record type, and are the
results of two separate calls to record constructors,
then
eqv
? returns
#f
should be replaced by:
If
obj
and
obj
are both records of the same mutable record type, and are the
results of two separate calls to record constructors,
then
eqv
? returns
#f
§ 6.2
In the
parent-rtd
clause, analogously to
make-record-constructor-descriptor
either or can evaluate to
#f
, according to rules analogous to those for
make-record-constructor-descriptor
§ 6.3
The sentence
"If
rtd
is a base record type and
protocol
is a procedure,
parent-constructor-descriptor
must be
#f
."
should be replaced by:
"If
rtd
is a base record type
parent-constructor-descriptor
must be
#f
."
The sentence:
"If
rtd
is an extension of another record type, and
parent-constructor-descriptor
or the
protocol
of
parent-constructor-descriptor
is
#f
protocol
must lso be
#f
, and a
default constructor descriptor as described above is also
assumed."
should be replaced by:
"If
rtd
is an extension of another record type and
parent-constructor-descriptor
is
#f
parent-constructor-descriptor
is treated as if it were a
constructor descriptor for the parent rtd of
rtd
with a
default protocol."
The examples for calls to
make-point/abs
and an
example for
cpoint-rgb
are
missing trailing parentheses, and should go like this:
(point-x (make-point/abs -1 -2)) => 1
(point-y (make-point/abs -1 -2)) => 2
...
(cpoint-rgb (make-cpoint -1 -3 'red)) => (rgb . red)
§ 7.1
The sentence
"If every
's evaluates to
#f
and there
is no
else
clause, then
raise
is re-invoked on the raised object
[...]"
should be replaced by
"If every
's evaluates to
#f
and there
is no
else
clause, then
raise-continuable
is invoked on the raised object
[...]"
The second example for
raise
is missing a parenthesis
after
make-violation
and should go like this:
(guard (con
((error? con)
(if (message-condition? con)
(display (condition-message con))
(display "an error has occurred"))
'error))
(raise
(condition
(make-violation)
(make-message-condition "I am an error"))))
=> &violation
exception
§ 7.2.1
The examples for
cond1-x
cond2-y
are lacking trailing parentheses and should go like this:
(cond1-x (condition foo bar)) => foo
(cond2-y (condition foo bar)) => bar
§ 8.1
The argument
port
in the template for
make-i/o-port-error
inappropraitely implies
that the argument must be a port, in conflict with the
description. The three occurrences of
port
in the
description should be replaced with
pobj
§ 8.2.4
The occurrences of
port
in the templates for
make-i/o-decoding-error
and
make-i/o-encoding-error
should be replaced
with
pobj
, and the occurrences of
char
in the description of
make-i/o-encoding-error
should be replaced with
cobj
. The description
of
make-i/o-encoding-error
should say that
cobj
should be the character that could not be
encoded.
§ 8.2.7
The following note should be added to the description of
make-custom-textual-input-port
``Even when the
get-position
procedure is supplied, the
port-position
procedure cannot generally return a precise
value for a custom textual input port if data has been
read from the port.''
§ 8.2.10
In the description of
make-custom-binary-output-port
, the sentence
"If
count
is 0, the
write!
procedure
should have the effect of passing an end-of-file object to the
byte sink."
should be deleted (it was left over from an earlier
revision). The corresponding sentence in the description of
make-custom-textual-output-port
should also be
deleted.
§ 8.2.13
The following note should be added to the description of
make-custom-binary-input/output-port
``Unless both
get-position
and
set-position!
procedures are
supplied, a put operation cannot precisely position the port for output
to a custom binary input/output port after data has been read from
the port.''
The following note should be added to the description of
make-custom-textual-input/output-port
``Even when both
get-position
and
set-position!
procedures are
supplied, the
port-position
procedure cannot generally return a
precise value for a custom textual input/output port, and a put operation
cannot precisely position the port for output, after data has
been read from the port.''
§ 11.2
In the entry for
fx-
, the exception mentioned
should have condition type
&implementation-restriction
(as explained in
the introduction of that section), not
&assertion
The specification of
fxcopy-bit-field
should be
clarified to say
"the bits in
fx
from position 0 (inclusive) to position
fx
fx
(exclusive)"
instead of just
"the corresponding bits in
fx
".
The code illustrating the computation performed by
fxcopy-bit-field
should be replaced by the
following:
(let* ((n
fx
(start
fx
(end
fx
(from
fx
(mask1 (fxarithmetic-shift-left -1 start))
(mask2 (fxnot
(fxarithmetic-shift-left -1 end)))
(mask (fxand mask1 mask2))
(mask3 (fxnot (fxarithmetic-shift-left
-1 (- end start)))))
(fxif mask
(fxarithmetic-shift-left (fxand from mask3)
start)
to))
In the code specifying the computation for
fxbit-count
, "
ei
" should be "
fx
".
In the specification of
fxbit-set?
the sentence
Fx
must be non-negative
and less than
(fixnum-width)
."
should be replaced by
Fx
must be non-negative."
Also, the code describing its computation should be changed
to:
(if (fx>=?
fx
(fx- (fixnum-width) 1))
(fxnegative?
fx
(not
(fxzero?
(fxand
fx
(fxarithmetic-shift-left 1
fx
)))))
In the specification of
fxcopy-bit
, the
sentence
Fx
must be non-negative
and less than
(fixnum-width)
."
should be replaced by
Fx
must be non-negative and less
than
- 1."
In the entry for
fxrotate-bit-field
, the
sentence
Fx
must be less than the difference
between
fx
and
fx
."
should be changed to:
Fx
must be less than or equal to the difference
between
fx
and
fx
."
The code used to illustrate the computation performed by
fxrotate-bit-field
should be changed to:
(let* ((n
fx
(start
fx
(end
fx
(count
fx
(width (fx- end start)))
(fxcopy-bit-field n start end
(fxior
(fxarithmetic-shift-left
(fxbit-field n start (fx- end count)) count)
(fxarithmetic-shift-right
(fxbit-field n start end) (fx- width count))))))
§ 11.3
The examples for
fl=?
etc. lack the trailing
in their names.
In the description of
fldiv
etc, the wording:
"For zero divisors, these procedures may return a NaN or
some unspecified flonum."
should be replaced by
"In the cases where the mathematical
requirements in section
11.7.3 cannot be satisfied by any number object, either an
exception is raised with condition type
&implementation-restriction
, or unspecified flonums (one
for for
fldiv
flmod
fldiv0
and
flmod0
, two for
fldiv-and-mod
and
fldiv0-and-mod0
) are
returned."
In the description of
flexpt
, the sentence
"If
fl
is zero, then the result is
zero."
should be replaced by:
"If
fl
and
fl
are both zero, the result is
1.0. If
fl
is zero and
fl
is positive, the result is zero.
If
fl
is zero and
fl
is negative, the result may be a NaN, or may be
some unspecified flonum."
The
make-no-infinities-violation
and
make-no-nans-violation
procedures take no
arguments.
§ 11.4
In the specification of
bitwise-copy-bit
"[...] by the
ei
bit of
ei
should be replaced by
"[...] by
ei
In the specification of
bitwise-copy-bit-field
"... fixnum result of the following computation:"
should be replaced by
"... result of the following computation:"
The specification of
bitwise-copy-bit-field
should be
clarified to say
"the bits in
ei
from position 0 (inclusive) to position
ei
ei
(exclusive)"
instead of just
"the corresponding bits in
ei
".
§ 12.1
The remark "An algebra that defines how marks and substitutions work more
precisely is given in section~2.4 of Oscar Waddell's PhD
thesis." is somewhat misleading and should be qualified as
follows:
"Note, however, that Waddell's
thesis describes slightly different semantics for
bound-identifier=?
- it specifies that for two identifiers to be
equal in the sense of
bound-identifier=?
, they must have the same marks and be equal in
the sense of
free-identifier=?
, whereas this report requires
instead that they must have the same marks and have the same name."
§ 12.4
The last example in this section:
p => (15 5)
should be:
p => (15 . 5)
§ 12.6
The example definition of the
include
macro
uses
(open-file-input-port fn)
to open the file, which would result in a binary input port.
Instead, a textual input port should be opened, for example via:
(open-file-input-port fn (file-options) (buffer-mode block) (native-transcoder))
§ 12.8
The sample definition of
identifier-syntax
is
incorrect and should be as follows:
(define-syntax identifier-syntax
(lambda (x)
(syntax-case x (set!)
[(_ e)
#'(lambda (x)
(syntax-case x ()
[id (identifier? #'id) #'e]
[(_ x (... ...)) #'(e x (... ...))]))]
[(_ (id exp1) ((set! var val) exp2))
(and (identifier? #'id) (identifier? #'var))
#'(make-variable-transformer
(lambda (x)
(syntax-case x (set!)
[(set! var val) #'exp2]
[(id x (... ...)) #'(exp1 x (... ...))]
[id (identifier? #'id) #'exp1])))])))
§ 13.2
The parameter to
hashtable?
should be
obj
instead of
hashtable
hashtable?
can be called with any object.
The description of
hashtable-entries
should
contain an explanatory note saying that the order of the entries
in the result vectors may be different from the example.
§ 14
The word "value" in the description of
enum-set-indexer
should be replaced with "symbol"
to avoid implying that the procedure returned by
enum-set-indexer
accepts arbitrary types of
values.
There's an extra parenthesis at the end of the code example
for
enum-set-projection
§ 16
The examples for
environment
both lack imports
of
(rnrs eval)
§ 16
The requirement that
eval
raise an exception with
condition type
&assertion
if applied to an
expression containing an assignment to one of the variables in
the environment should be replaced with a requirement that it
raise an exception with condition type
&syntax
for consistency with treatement
of similar situations as syntax violations in Section 7.1 of the
base document.