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revert r5rs changes

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* doc/r5rs/r5rs.texi: Reverts the recent changes to r5rs.texi.
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Andy Wingo 2012-02-02 23:38:01 +01:00
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doc/r5rs/r5rs.texi
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@ -2155,7 +2155,7 @@ and @r{<body>} should be a sequence of
one or more expressions. one or more expressions.
@emph{Semantics:} @emph{Semantics:}
@samp{let*} is similar to @samp{let}, but the bindings are performed @samp{Let*} is similar to @samp{let}, but the bindings are performed
sequentially from left to right, and the region of a binding indicated sequentially from left to right, and the region of a binding indicated
@cindex @w{region} @cindex @w{region}
by @samp{(@r{<variable>} @r{<init>})} is that part of the @samp{let*} by @samp{(@r{<variable>} @r{<init>})} is that part of the @samp{let*}
@ -2271,12 +2271,12 @@ output.
@deffn {library syntax} do ((@r{<variable1>} @r{<init1>} @r{<step1>}) @dots{}) (@r{<test>} @r{<expression>} @dots{}) @r{<command>} @dots{} @deffn {library syntax} do ((@r{<variable1>} @r{<init1>} @r{<step1>}) @dots{}) (@r{<test>} @r{<expression>} @dots{}) @r{<command>} @dots{}
@cindex @w{do} @cindex @w{do}
@samp{do} is an iteration construct. It specifies a set of variables to @samp{Do} is an iteration construct. It specifies a set of variables to
be bound, how they are to be initialized at the start, and how they are be bound, how they are to be initialized at the start, and how they are
to be updated on each iteration. When a termination condition is met, to be updated on each iteration. When a termination condition is met,
the loop exits after evaluating the @r{<expression>}s. the loop exits after evaluating the @r{<expression>}s.
@samp{do} expressions are evaluated as follows: @samp{Do} expressions are evaluated as follows:
The @r{<init>} expressions are evaluated (in some unspecified order), The @r{<init>} expressions are evaluated (in some unspecified order),
the @r{<variable>}s are bound to fresh locations, the results of the the @r{<variable>}s are bound to fresh locations, the results of the
@r{<init>} expressions are stored in the bindings of the @r{<init>} expressions are stored in the bindings of the
@ -2595,7 +2595,7 @@ bindings that may surround the use of the macro.
@samp{let-syntax} and @samp{letrec-syntax} are @samp{Let-syntax} and @samp{letrec-syntax} are
analogous to @samp{let} and @samp{letrec}, but they bind analogous to @samp{let} and @samp{letrec}, but they bind
syntactic keywords to macro transformers instead of binding variables syntactic keywords to macro transformers instead of binding variables
to locations that contain values. Syntactic keywords may also be to locations that contain values. Syntactic keywords may also be
@ -3254,7 +3254,7 @@ value (@t{#t} or @t{#f}). An @dfn{equivalence predicate} is
the computational analogue of a mathematical equivalence relation (it is the computational analogue of a mathematical equivalence relation (it is
symmetric, reflexive, and transitive). Of the equivalence predicates symmetric, reflexive, and transitive). Of the equivalence predicates
described in this section, @samp{eq?} is the finest or most described in this section, @samp{eq?} is the finest or most
discriminating, and @samp{equal?} is the coarsest. @samp{eqv?} is discriminating, and @samp{equal?} is the coarsest. @samp{Eqv?} is
slightly less discriminating than @samp{eq?}. slightly less discriminating than @samp{eq?}.
@ignore todo @ignore todo
Pitman doesn't like Pitman doesn't like
@ -3419,9 +3419,9 @@ boolean.
The next set of examples shows the use of @samp{eqv?} with procedures The next set of examples shows the use of @samp{eqv?} with procedures
that have local state. @samp{gen-counter} must return a distinct that have local state. @samp{Gen-counter} must return a distinct
procedure every time, since each procedure has its own internal counter. procedure every time, since each procedure has its own internal counter.
@samp{gen-loser}, however, returns equivalent procedures each time, since @samp{Gen-loser}, however, returns equivalent procedures each time, since
the local state does not affect the value or side effects of the the local state does not affect the value or side effects of the
procedures. procedures.
@ -3500,17 +3500,17 @@ bit pattern to represent both.
@deffn {procedure} eq? obj1 obj2 @deffn {procedure} eq? obj1 obj2
@samp{eq?} is similar to @samp{eqv?} except that in some cases it is @samp{Eq?} is similar to @samp{eqv?} except that in some cases it is
capable of discerning distinctions finer than those detectable by capable of discerning distinctions finer than those detectable by
@samp{eqv?}. @samp{eqv?}.
@samp{eq?} and @samp{eqv?} are guaranteed to have the same @samp{Eq?} and @samp{eqv?} are guaranteed to have the same
behavior on symbols, booleans, the empty list, pairs, procedures, behavior on symbols, booleans, the empty list, pairs, procedures,
and non-empty and non-empty
strings and vectors. @samp{eq?}'s behavior on numbers and characters is strings and vectors. @samp{Eq?}'s behavior on numbers and characters is
implementation-dependent, but it will always return either true or implementation-dependent, but it will always return either true or
false, and will return true only when @samp{eqv?} would also return false, and will return true only when @samp{eqv?} would also return
true. @samp{eq?} may also behave differently from @samp{eqv?} on empty true. @samp{Eq?} may also behave differently from @samp{eqv?} on empty
vectors and empty strings. vectors and empty strings.
@ -3549,7 +3549,7 @@ more efficiently than @samp{eqv?}, for example, as a simple pointer
comparison instead of as some more complicated operation. One reason is comparison instead of as some more complicated operation. One reason is
that it may not be possible to compute @samp{eqv?} of two numbers in that it may not be possible to compute @samp{eqv?} of two numbers in
constant time, whereas @samp{eq?} implemented as pointer comparison will constant time, whereas @samp{eq?} implemented as pointer comparison will
always finish in constant time. @samp{eq?} may be used like @samp{eqv?} always finish in constant time. @samp{Eq?} may be used like @samp{eqv?}
in applications using procedures to implement objects with state since in applications using procedures to implement objects with state since
it obeys the same constraints as @samp{eqv?}. it obeys the same constraints as @samp{eqv?}.
@end quotation @end quotation
@ -3561,10 +3561,10 @@ it obeys the same constraints as @samp{eqv?}.
@deffn {library procedure} equal? obj1 obj2 @deffn {library procedure} equal? obj1 obj2
@samp{equal?} recursively compares the contents of pairs, vectors, and @samp{Equal?} recursively compares the contents of pairs, vectors, and
strings, applying @samp{eqv?} on other objects such as numbers and symbols. strings, applying @samp{eqv?} on other objects such as numbers and symbols.
A rule of thumb is that objects are generally @samp{equal?} if they print A rule of thumb is that objects are generally @samp{equal?} if they print
the same. @samp{equal?} may fail to terminate if its arguments are the same. @samp{Equal?} may fail to terminate if its arguments are
circular data structures. circular data structures.
@ -4211,7 +4211,7 @@ however, they return the additive or multiplicative inverse of their argument.
@deffn {library procedure} abs x @deffn {library procedure} abs x
@samp{abs} returns the absolute value of its argument. @samp{Abs} returns the absolute value of its argument.
@c - {\cf Abs} is exactness preserving when its argument is real. @c - {\cf Abs} is exactness preserving when its argument is real.
@format @format
@ -4344,17 +4344,17 @@ More description and examples needed.
These procedures return integers. These procedures return integers.
@samp{floor} returns the largest integer not larger than @var{x}. @samp{Floor} returns the largest integer not larger than @var{x}.
@samp{ceiling} returns the smallest integer not smaller than @var{x}. @samp{Ceiling} returns the smallest integer not smaller than @var{x}.
@samp{truncate} returns the integer closest to @var{x} whose absolute @samp{Truncate} returns the integer closest to @var{x} whose absolute
value is not larger than the absolute value of @var{x}. @samp{tound} returns the value is not larger than the absolute value of @var{x}. @samp{Round} returns the
closest integer to @var{x}, rounding to even when @var{x} is halfway between two closest integer to @var{x}, rounding to even when @var{x} is halfway between two
integers. integers.
@quotation @quotation
@emph{Rationale:} @emph{Rationale:}
@samp{round} rounds to even for consistency with the default rounding @samp{Round} rounds to even for consistency with the default rounding
mode specified by the IEEE floating point standard. mode specified by the IEEE floating point standard.
@end quotation @end quotation
@ -4393,7 +4393,7 @@ result should be passed to the @samp{inexact->exact} procedure.
@c - \proto{rationalize}{ x}{procedure} @c - \proto{rationalize}{ x}{procedure}
@samp{rationalize} returns the @emph{simplest} rational number @samp{Rationalize} returns the @emph{simplest} rational number
differing from @var{x} by no more than @var{y}. A rational number r_1 is differing from @var{x} by no more than @var{y}. A rational number r_1 is
@emph{simpler} than another rational number @emph{simpler} than another rational number
@cindex @w{simplest rational} @cindex @w{simplest rational}
@ -4556,7 +4556,7 @@ for some integer n.
@quotation @quotation
@emph{Rationale:} @emph{Rationale:}
@samp{magnitude} is the same as @code{abs} for a real argument, @samp{Magnitude} is the same as @code{abs} for a real argument,
@vindex @w{abs} @vindex @w{abs}
but @samp{abs} must be present in all implementations, whereas but @samp{abs} must be present in all implementations, whereas
@samp{magnitude} need only be present in implementations that support @samp{magnitude} need only be present in implementations that support
@ -4571,7 +4571,7 @@ general complex numbers.
@deffn {procedure} exact->inexact @var{z} @deffn {procedure} exact->inexact @var{z}
@deffnx {procedure} inexact->exact @var{z} @deffnx {procedure} inexact->exact @var{z}
@samp{exact->inexact} returns an @r{inexact} representation of @var{z}. @samp{Exact->inexact} returns an @r{inexact} representation of @var{z}.
The value returned is the The value returned is the
@r{inexact} number that is numerically closest to the argument. @r{inexact} number that is numerically closest to the argument.
@c %R4%%For @c %R4%%For
@ -4580,7 +4580,7 @@ The value returned is the
If an @r{exact} argument has no reasonably close @r{inexact} equivalent, If an @r{exact} argument has no reasonably close @r{inexact} equivalent,
then a violation of an implementation restriction may be reported. then a violation of an implementation restriction may be reported.
@samp{inexact->exact} returns an @r{exact} representation of @samp{Inexact->exact} returns an @r{exact} representation of
@var{z}. The value returned is the @r{exact} number that is numerically @var{z}. The value returned is the @r{exact} number that is numerically
closest to the argument. closest to the argument.
@c %R4%% For \tupe{inexact} arguments which have no @c %R4%% For \tupe{inexact} arguments which have no
@ -4615,7 +4615,7 @@ implementation-dependent range. See section @ref{Implementation restrictions}.
@deffn {procedure} number->string z @deffn {procedure} number->string z
@deffnx {procedure} number->string z radix @deffnx {procedure} number->string z radix
@var{radix} must be an exact integer, either 2, 8, 10, or 16. If omitted, @var{Radix} must be an exact integer, either 2, 8, 10, or 16. If omitted,
@var{radix} defaults to 10. @var{radix} defaults to 10.
The procedure @samp{number->string} takes a The procedure @samp{number->string} takes a
number and a radix and returns as a string an external representation of number and a radix and returns as a string an external representation of
@ -4674,7 +4674,7 @@ allows for infinities, NaNs, and non-flonum representations.
@c for the third argument. @c for the third argument.
Returns a number of the maximally precise representation expressed by the Returns a number of the maximally precise representation expressed by the
given @var{string}. @var{radix} must be an exact integer, either 2, 8, 10, given @var{string}. @var{Radix} must be an exact integer, either 2, 8, 10,
or 16. If supplied, @var{radix} is a default radix that may be overridden or 16. If supplied, @var{radix} is a default radix that may be overridden
by an explicit radix prefix in @var{string} (e.g. @t{"#o177"}). If @var{radix} by an explicit radix prefix in @var{string} (e.g. @t{"#o177"}). If @var{radix}
is not supplied, then the default radix is 10. If @var{string} is not is not supplied, then the default radix is 10. If @var{string} is not
@ -4695,7 +4695,7 @@ returns @t{#f}.
@quotation @quotation
@emph{Note:} @emph{Note:}
The domain of @samp{string->number} may be restricted by implementations The domain of @samp{string->number} may be restricted by implementations
in the following ways. @samp{string->number} is permitted to return in the following ways. @samp{String->number} is permitted to return
@t{#f} whenever @var{string} contains an explicit radix prefix. @t{#f} whenever @var{string} contains an explicit radix prefix.
If all numbers supported by an implementation are real, then If all numbers supported by an implementation are real, then
@samp{string->number} is permitted to return @t{#f} whenever @samp{string->number} is permitted to return @t{#f} whenever
@ -4802,7 +4802,7 @@ in programs.
@deffn {library procedure} not obj @deffn {library procedure} not obj
@samp{not} returns @t{#t} if @var{obj} is false, and returns @samp{Not} returns @t{#t} if @var{obj} is false, and returns
@t{#f} otherwise. @t{#f} otherwise.
@ -4824,7 +4824,7 @@ in programs.
@deffn {library procedure} boolean? obj @deffn {library procedure} boolean? obj
@samp{boolean?} returns @t{#t} if @var{obj} is either @t{#t} or @samp{Boolean?} returns @t{#t} if @var{obj} is either @t{#t} or
@t{#f} and returns @t{#f} otherwise. @t{#f} and returns @t{#f} otherwise.
@ -5011,7 +5011,7 @@ parse Scheme programs. See section @ref{External representations}.
@deffn {procedure} pair? obj @deffn {procedure} pair? obj
@samp{pair?} returns @t{#t} if @var{obj} is a pair, and otherwise @samp{Pair?} returns @t{#t} if @var{obj} is a pair, and otherwise
returns @t{#f}. returns @t{#f}.
@ -5295,7 +5295,7 @@ in reverse order.
Returns the sublist of @var{list} obtained by omitting the first @var{k} Returns the sublist of @var{list} obtained by omitting the first @var{k}
elements. It is an error if @var{list} has fewer than @var{k} elements. elements. It is an error if @var{list} has fewer than @var{k} elements.
@samp{list-tail} could be defined by @samp{List-tail} could be defined by
@format @format
@ -5356,7 +5356,7 @@ These procedures return the first sublist of @var{list} whose car is
returned by @t{(list-tail @var{list} @var{k})} for @var{k} less returned by @t{(list-tail @var{list} @var{k})} for @var{k} less
than the length of @var{list}. If than the length of @var{list}. If
@var{obj} does not occur in @var{list}, then @t{#f} (not the empty list) is @var{obj} does not occur in @var{list}, then @t{#f} (not the empty list) is
returned. @samp{memq} uses @samp{eq?} to compare @var{obj} with the elements of returned. @samp{Memq} uses @samp{eq?} to compare @var{obj} with the elements of
@var{list}, while @samp{memv} uses @samp{eqv?} and @samp{member} uses @samp{equal?}. @var{list}, while @samp{memv} uses @samp{eqv?} and @samp{member} uses @samp{equal?}.
@ -5381,10 +5381,10 @@ returned. @samp{memq} uses @samp{eq?} to compare @var{obj} with the elements of
@deffnx {library procedure} assv obj alist @deffnx {library procedure} assv obj alist
@deffnx {library procedure} assoc obj alist @deffnx {library procedure} assoc obj alist
@var{alist} (for ``association list'') must be a list of @var{Alist} (for ``association list'') must be a list of
pairs. These procedures find the first pair in @var{alist} whose car field is @var{obj}, pairs. These procedures find the first pair in @var{alist} whose car field is @var{obj},
and returns that pair. If no pair in @var{alist} has @var{obj} as its and returns that pair. If no pair in @var{alist} has @var{obj} as its
car, then @t{#f} (not the empty list) is returned. @samp{assq} uses car, then @t{#f} (not the empty list) is returned. @samp{Assq} uses
@samp{eq?} to compare @var{obj} with the car fields of the pairs in @var{alist}, @samp{eq?} to compare @var{obj} with the car fields of the pairs in @var{alist},
while @samp{assv} uses @samp{eqv?} and @samp{assoc} uses @samp{equal?}. while @samp{assv} uses @samp{eqv?} and @samp{assoc} uses @samp{equal?}.
@ -5830,9 +5830,10 @@ Returns @t{#t} if @var{obj} is a string, otherwise returns @t{#f}.
@c \domain{\vr{k} must be a non-negative integer, and \var{char} must be @c \domain{\vr{k} must be a non-negative integer, and \var{char} must be
@c a character.} @c a character.}
@samp{make-string} returns a newly allocated string of length @var{k}. @samp{Make-string} returns a newly allocated string of
If @var{char} is given, then all elements of the string are initialized length @var{k}. If @var{char} is given, then all elements of the string
to @var{char}, otherwise the contents of the string are unspecified. are initialized to @var{char}, otherwise the contents of the
@var{string} are unspecified.
@end deffn @end deffn
@ -5854,7 +5855,7 @@ Returns the number of characters in the given @var{string}.
@deffn {procedure} string-ref string @var{k} @deffn {procedure} string-ref string @var{k}
@var{k} must be a valid index of @var{string}. @var{k} must be a valid index of @var{string}.
@samp{string-ref} returns character @var{k} of @var{string} using zero-origin indexing. @samp{String-ref} returns character @var{k} of @var{string} using zero-origin indexing.
@end deffn @end deffn
@ -5866,7 +5867,7 @@ Returns the number of characters in the given @var{string}.
@var{k} must be a valid index of @var{string} @var{k} must be a valid index of @var{string}
@c , and \var{char} must be a character @c , and \var{char} must be a character
. .
@samp{string-set!} stores @var{char} in element @var{k} of @var{string} @samp{String-set!} stores @var{char} in element @var{k} of @var{string}
and returns an unspecified value. and returns an unspecified value.
@c <!> @c <!>
@ -5892,7 +5893,7 @@ and returns an unspecified value.
Returns @t{#t} if the two strings are the same length and contain the same Returns @t{#t} if the two strings are the same length and contain the same
characters in the same positions, otherwise returns @t{#f}. characters in the same positions, otherwise returns @t{#f}.
@samp{string-ci=?} treats @samp{String-ci=?} treats
upper and lower case letters as though they were the same character, but upper and lower case letters as though they were the same character, but
@samp{string=?} treats upper and lower case as distinct characters. @samp{string=?} treats upper and lower case as distinct characters.
@ -5926,13 +5927,13 @@ the corresponding numerical predicates.
@deffn {library procedure} substring string start end @deffn {library procedure} substring string start end
@var{string} must be a string, and @var{start} and @var{end} @var{String} must be a string, and @var{start} and @var{end}
must be exact integers satisfying must be exact integers satisfying
@center 0 <= @var{start} <= @var{end} <= @w{@t{(string-length @var{string})@r{.}}} @center 0 <= @var{start} <= @var{end} <= @w{@t{(string-length @var{string})@r{.}}}
@samp{substring} returns a newly allocated string formed from the characters of @samp{Substring} returns a newly allocated string formed from the characters of
@var{string} beginning with index @var{start} (inclusive) and ending with index @var{string} beginning with index @var{start} (inclusive) and ending with index
@var{end} (exclusive). @var{end} (exclusive).
@end deffn @end deffn
@ -5951,10 +5952,10 @@ given strings.
@deffn {library procedure} string->list string @deffn {library procedure} string->list string
@deffnx {library procedure} list->string list @deffnx {library procedure} list->string list
@samp{string->list} returns a newly allocated list of the @samp{String->list} returns a newly allocated list of the
characters that make up the given string. @samp{list->string} characters that make up the given string. @samp{List->string}
returns a newly allocated string formed from the characters in the list returns a newly allocated string formed from the characters in the list
@var{list}, which must be a list of characters. @samp{string->list} @var{list}, which must be a list of characters. @samp{String->list}
and @samp{list->string} are and @samp{list->string} are
inverses so far as @samp{equal?} is concerned. inverses so far as @samp{equal?} is concerned.
@c Implementations that provide @c Implementations that provide
@ -6077,7 +6078,7 @@ Returns the number of elements in @var{vector} as an exact integer.
@deffn {procedure} vector-ref vector k @deffn {procedure} vector-ref vector k
@var{k} must be a valid index of @var{vector}. @var{k} must be a valid index of @var{vector}.
@samp{vector-ref} returns the contents of element @var{k} of @samp{Vector-ref} returns the contents of element @var{k} of
@var{vector}. @var{vector}.
@ -6101,7 +6102,7 @@ Returns the number of elements in @var{vector} as an exact integer.
@deffn {procedure} vector-set! vector k obj @deffn {procedure} vector-set! vector k obj
@var{k} must be a valid index of @var{vector}. @var{k} must be a valid index of @var{vector}.
@samp{vector-set!} stores @var{obj} in element @var{k} of @var{vector}. @samp{Vector-set!} stores @var{obj} in element @var{k} of @var{vector}.
The value returned by @samp{vector-set!} is unspecified. The value returned by @samp{vector-set!} is unspecified.
@c <!> @c <!>
@ -6124,8 +6125,8 @@ The value returned by @samp{vector-set!} is unspecified.
@deffn {library procedure} vector->list vector @deffn {library procedure} vector->list vector
@deffnx {library procedure} list->vector list @deffnx {library procedure} list->vector list
@samp{vector->list} returns a newly allocated list of the objects contained @samp{Vector->list} returns a newly allocated list of the objects contained
in the elements of @var{vector}. @samp{list->vector} returns a newly in the elements of @var{vector}. @samp{List->vector} returns a newly
created vector initialized to the elements of the list @var{list}. created vector initialized to the elements of the list @var{list}.
@ -6193,7 +6194,7 @@ Returns @t{#t} if @var{obj} is a procedure, otherwise returns @t{#f}.
@deffn {procedure} apply proc arg1 @dots{} args @deffn {procedure} apply proc arg1 @dots{} args
@var{proc} must be a procedure and @var{args} must be a list. @var{Proc} must be a procedure and @var{args} must be a list.
Calls @var{proc} with the elements of the list Calls @var{proc} with the elements of the list
@samp{(append (list @var{arg1} @dots{},) @var{args})} as the actual @samp{(append (list @var{arg1} @dots{},) @var{args})} as the actual
arguments. arguments.
@ -6215,13 +6216,13 @@ arguments.
@deffn {library procedure} map proc list1 list2 @dots{} @deffn {library procedure} map proc list1 list2 @dots{},
The @var{list}s must be lists, and @var{proc} must be a The @var{list}s must be lists, and @var{proc} must be a
procedure taking as many arguments as there are @i{list}s procedure taking as many arguments as there are @i{list}s
and returning a single value. If more and returning a single value. If more
than one @var{list} is given, then they must all be the same length. than one @var{list} is given, then they must all be the same length.
@samp{map} applies @var{proc} element-wise to the elements of the @samp{Map} applies @var{proc} element-wise to the elements of the
@var{list}s and returns a list of the results, in order. @var{list}s and returns a list of the results, in order.
The dynamic order in which @var{proc} is applied to the elements of the The dynamic order in which @var{proc} is applied to the elements of the
@var{list}s is unspecified. @var{list}s is unspecified.
@ -6308,7 +6309,7 @@ time, the previously computed value is returned.
@end format @end format
@samp{force} and @samp{delay} are mainly intended for programs written in @samp{Force} and @samp{delay} are mainly intended for programs written in
functional style. The following examples should not be considered to functional style. The following examples should not be considered to
illustrate good programming style, but they illustrate the property that illustrate good programming style, but they illustrate the property that
only one value is computed for a promise, no matter how many times it is only one value is computed for a promise, no matter how many times it is
@ -6465,7 +6466,7 @@ and @samp{+}:
@deffn {procedure} call-with-current-continuation proc @deffn {procedure} call-with-current-continuation proc
@var{proc} must be a procedure of one @var{Proc} must be a procedure of one
argument. The procedure @samp{call-with-current-continuation} packages argument. The procedure @samp{call-with-current-continuation} packages
up the current continuation (see the rationale below) as an ``escape up the current continuation (see the rationale below) as an ``escape
procedure'' and passes it as an argument to procedure'' and passes it as an argument to
@ -6545,7 +6546,7 @@ the answer to the top level continuation to be printed. Normally these
ubiquitous continuations are hidden behind the scenes and programmers do not ubiquitous continuations are hidden behind the scenes and programmers do not
think much about them. On rare occasions, however, a programmer may think much about them. On rare occasions, however, a programmer may
need to deal with continuations explicitly. need to deal with continuations explicitly.
@samp{call-with-current-continuation} allows Scheme programmers to do @samp{Call-with-current-continuation} allows Scheme programmers to do
that by creating a procedure that acts just like the current that by creating a procedure that acts just like the current
continuation. continuation.
@ -6615,11 +6616,11 @@ continuation of the call to @t{call-with-values}.
@deffn {procedure} dynamic-wind before thunk after @deffn {procedure} dynamic-wind before thunk after
Calls @var{thunk} without arguments, returning the result(s) of this call. Calls @var{thunk} without arguments, returning the result(s) of this call.
@var{before} and @var{after} are called, also without arguments, as required @var{Before} and @var{after} are called, also without arguments, as required
by the following rules (note that in the absence of calls to continuations by the following rules (note that in the absence of calls to continuations
captured using @code{call-with-current-continuation} the three arguments are captured using @code{call-with-current-continuation} the three arguments are
@vindex @w{call-with-current-continuation} @vindex @w{call-with-current-continuation}
called once each, in order). @var{before} is called whenever execution called once each, in order). @var{Before} is called whenever execution
enters the dynamic extent of the call to @var{thunk} and @var{after} is called enters the dynamic extent of the call to @var{thunk} and @var{after} is called
whenever it exits that dynamic extent. The dynamic extent of a procedure whenever it exits that dynamic extent. The dynamic extent of a procedure
call is the period between when the call is initiated and when it call is the period between when the call is initiated and when it
@ -6702,7 +6703,7 @@ extent of a call to @var{before} or @var{after} is undefined.
@deffn {procedure} eval expression environment-specifier @deffn {procedure} eval expression environment-specifier
Evaluates @var{expression} in the specified environment and returns its value. Evaluates @var{expression} in the specified environment and returns its value.
@var{expression} must be a valid Scheme expression represented as data, @var{Expression} must be a valid Scheme expression represented as data,
and @var{environment-specifier} must be a value returned by one of the and @var{environment-specifier} must be a value returned by one of the
three procedures described below. three procedures described below.
Implementations may extend @samp{eval} to allow non-expression programs Implementations may extend @samp{eval} to allow non-expression programs
@ -6730,13 +6731,13 @@ allowed to create new bindings in the environments associated with
@deffn {procedure} scheme-report-environment version @deffn {procedure} scheme-report-environment version
@deffnx {procedure} null-environment version @deffnx {procedure} null-environment version
@var{version} must be the exact integer @samp{5}, @var{Version} must be the exact integer @samp{5},
corresponding to this revision of the Scheme report (the corresponding to this revision of the Scheme report (the
Revised^5 Report on Scheme). Revised^5 Report on Scheme).
@samp{scheme-report-environment} returns a specifier for an @samp{Scheme-report-environment} returns a specifier for an
environment that is empty except for all bindings defined in environment that is empty except for all bindings defined in
this report that are either required or both optional and this report that are either required or both optional and
supported by the implementation. @samp{null-environment} returns supported by the implementation. @samp{Null-environment} returns
a specifier for an environment that is empty except for the a specifier for an environment that is empty except for the
(syntactic) bindings for all syntactic keywords defined in (syntactic) bindings for all syntactic keywords defined in
this report that are either required or both optional and this report that are either required or both optional and
@ -6796,7 +6797,7 @@ Haase: Mention that there are alternatives to files?
@deffn {library procedure} call-with-input-file string proc @deffn {library procedure} call-with-input-file string proc
@deffnx {library procedure} call-with-output-file string proc @deffnx {library procedure} call-with-output-file string proc
@var{string} should be a string naming a file, and @var{String} should be a string naming a file, and
@var{proc} should be a procedure that accepts one argument. @var{proc} should be a procedure that accepts one argument.
For @samp{call-with-input-file}, For @samp{call-with-input-file},
the file should already exist; for the file should already exist; for
@ -6861,8 +6862,8 @@ Returns the current default input or output port.
@deffn {optional procedure} with-input-from-file string thunk @deffn {optional procedure} with-input-from-file string thunk
@deffnx {optional procedure} with-output-to-file string thunk @deffnx {optional procedure} with-output-to-file string thunk
@var{string} should be a string naming a file, and @var{String} should be a string naming a file, and
@var{thunk} should be a procedure of no arguments. @var{proc} should be a procedure of no arguments.
For @samp{with-input-from-file}, For @samp{with-input-from-file},
the file should already exist; for the file should already exist; for
@samp{with-output-to-file}, @samp{with-output-to-file},
@ -6875,7 +6876,7 @@ connected to it is made the default value returned by
and the and the
@var{thunk} is called with no arguments. When the @var{thunk} returns, @var{thunk} is called with no arguments. When the @var{thunk} returns,
the port is closed and the previous default is restored. the port is closed and the previous default is restored.
@samp{with-input-from-file} and @samp{with-output-to-file} return(s) the @samp{With-input-from-file} and @samp{with-output-to-file} return(s) the
value(s) yielded by @var{thunk}. value(s) yielded by @var{thunk}.
If an escape procedure If an escape procedure
is used to escape from the continuation of these procedures, their is used to escape from the continuation of these procedures, their
@ -6968,10 +6969,10 @@ The input routines have some things in common, maybe explain here.
@deffn {library procedure} read @deffn {library procedure} read
@deffnx {library procedure} read port @deffnx {library procedure} read port
@samp{read} converts external representations of Scheme objects into the @samp{Read} converts external representations of Scheme objects into the
objects themselves. That is, it is a parser for the nonterminal objects themselves. That is, it is a parser for the nonterminal
<datum> (see sections @pxref{External representation} and <datum> (see sections @pxref{External representation} and
@pxref{Pairs and lists}). @samp{read} returns the next @pxref{Pairs and lists}). @samp{Read} returns the next
object parsable from the given input @var{port}, updating @var{port} to point to object parsable from the given input @var{port}, updating @var{port} to point to
the first character past the end of the external representation of the object. the first character past the end of the external representation of the object.
@ -6998,7 +6999,7 @@ a closed port.
Returns the next character available from the input @var{port}, updating Returns the next character available from the input @var{port}, updating
the @var{port} to point to the following character. If no more characters the @var{port} to point to the following character. If no more characters
are available, an end of file object is returned. @var{port} may be are available, an end of file object is returned. @var{Port} may be
omitted, in which case it defaults to the value returned by @samp{current-input-port}. omitted, in which case it defaults to the value returned by @samp{current-input-port}.
@end deffn @end deffn
@ -7011,7 +7012,7 @@ omitted, in which case it defaults to the value returned by @samp{current-input-
Returns the next character available from the input @var{port}, Returns the next character available from the input @var{port},
@emph{without} updating @emph{without} updating
the @var{port} to point to the following character. If no more characters the @var{port} to point to the following character. If no more characters
are available, an end of file object is returned. @var{port} may be are available, an end of file object is returned. @var{Port} may be
omitted, in which case it defaults to the value returned by @samp{current-input-port}. omitted, in which case it defaults to the value returned by @samp{current-input-port}.
@ -7049,13 +7050,13 @@ Returns @t{#t} if a character is ready on the input @var{port} and
returns @t{#f} otherwise. If @samp{char-ready} returns @t{#t} then returns @t{#f} otherwise. If @samp{char-ready} returns @t{#t} then
the next @samp{read-char} operation on the given @var{port} is guaranteed the next @samp{read-char} operation on the given @var{port} is guaranteed
not to hang. If the @var{port} is at end of file then @samp{char-ready?} not to hang. If the @var{port} is at end of file then @samp{char-ready?}
returns @t{#t}. @var{port} may be omitted, in which case it defaults to returns @t{#t}. @var{Port} may be omitted, in which case it defaults to
the value returned by @samp{current-input-port}. the value returned by @samp{current-input-port}.
@quotation @quotation
@emph{Rationale:} @emph{Rationale:}
@samp{char-ready?} exists to make it possible for a program to @samp{Char-ready?} exists to make it possible for a program to
accept characters from interactive ports without getting stuck waiting for accept characters from interactive ports without getting stuck waiting for
input. Any input editors associated with such ports must ensure that input. Any input editors associated with such ports must ensure that
characters whose existence has been asserted by @samp{char-ready?} cannot characters whose existence has been asserted by @samp{char-ready?} cannot
@ -7087,7 +7088,7 @@ that appear in the written representation are enclosed in doublequotes, and
within those strings backslash and doublequote characters are within those strings backslash and doublequote characters are
escaped by backslashes. escaped by backslashes.
Character objects are written using the @samp{#\} notation. Character objects are written using the @samp{#\} notation.
@samp{write} returns an unspecified value. The @samp{Write} returns an unspecified value. The
@var{port} argument may be omitted, in which case it defaults to the value @var{port} argument may be omitted, in which case it defaults to the value
returned by @samp{current-output-port}. returned by @samp{current-output-port}.
@ -7102,14 +7103,14 @@ Writes a representation of @var{obj} to the given @var{port}. Strings
that appear in the written representation are not enclosed in that appear in the written representation are not enclosed in
doublequotes, and no characters are escaped within those strings. Character doublequotes, and no characters are escaped within those strings. Character
objects appear in the representation as if written by @samp{write-char} objects appear in the representation as if written by @samp{write-char}
instead of by @samp{write}. @samp{display} returns an unspecified value. instead of by @samp{write}. @samp{Display} returns an unspecified value.
The @var{port} argument may be omitted, in which case it defaults to the The @var{port} argument may be omitted, in which case it defaults to the
value returned by @samp{current-output-port}. value returned by @samp{current-output-port}.
@quotation @quotation
@emph{Rationale:} @emph{Rationale:}
@samp{write} is intended @samp{Write} is intended
for producing mach@-ine-readable output and @samp{display} is for producing for producing mach@-ine-readable output and @samp{display} is for producing
human-readable output. Implementations that allow ``slashification'' human-readable output. Implementations that allow ``slashification''
within symbols will probably want @samp{write} but not @samp{display} to within symbols will probably want @samp{write} but not @samp{display} to
@ -7162,13 +7163,13 @@ Fix
@c \domain{\var{Filename} should be a string naming an existing file @c \domain{\var{Filename} should be a string naming an existing file
@c containing Scheme source code.} The {\cf load} procedure reads @c containing Scheme source code.} The {\cf load} procedure reads
@var{filename} should be a string naming an existing file @var{Filename} should be a string naming an existing file
containing Scheme source code. The @samp{load} procedure reads containing Scheme source code. The @samp{load} procedure reads
expressions and definitions from the file and evaluates them expressions and definitions from the file and evaluates them
sequentially. It is unspecified whether the results of the expressions sequentially. It is unspecified whether the results of the expressions
are printed. The @samp{load} procedure does not affect the values are printed. The @samp{load} procedure does not affect the values
returned by @samp{current-input-port} and @samp{current-output-port}. returned by @samp{current-input-port} and @samp{current-output-port}.
@samp{load} returns an unspecified value. @samp{Load} returns an unspecified value.
@quotation @quotation
@ -7185,7 +7186,7 @@ implementations.
@deffn {optional procedure} transcript-on filename @deffn {optional procedure} transcript-on filename
@deffnx {optional procedure} transcript-off @deffnx {optional procedure} transcript-off
@var{filename} must be a string naming an output file to be @var{Filename} must be a string naming an output file to be
created. The effect of @samp{transcript-on} is to open the named file created. The effect of @samp{transcript-on} is to open the named file
for output, and to cause a transcript of subsequent interaction between for output, and to cause a transcript of subsequent interaction between
the user and the Scheme system to be written to the file. The the user and the Scheme system to be written to the file. The
@ -7959,7 +7960,7 @@ of the main body of the report. The rewrite rules for derived expressions
have been replaced with macro definitions. There are no reserved identifiers. have been replaced with macro definitions. There are no reserved identifiers.
@item @item
@samp{syntax-rules} now allows vector patterns. @samp{Syntax-rules} now allows vector patterns.
@item @item
Multiple-value returns, @samp{eval}, and @samp{dynamic-wind} have Multiple-value returns, @samp{eval}, and @samp{dynamic-wind} have
@ -8073,7 +8074,7 @@ programs, implementations, and other material related to Scheme.
@c -*- Mode: Lisp; Package: SCHEME; Syntax: Common-lisp -*- @c -*- Mode: Lisp; Package: SCHEME; Syntax: Common-lisp -*-
@samp{integrate-system} integrates the system @samp{Integrate-system} integrates the system
@center y_k^^ = f_k(y_1, y_2, @dots{}, y_n), k = 1, @dots{}, n @center y_k^^ = f_k(y_1, y_2, @dots{}, y_n), k = 1, @dots{}, n
@ -8104,8 +8105,8 @@ system states.
@end example @end example
@samp{runge-kutta-4} takes a function, @t{f}, that produces a @samp{Runge-Kutta-4} takes a function, @t{f}, that produces a
system derivative from a system state. @samp{runge-kutta-4} system derivative from a system state. @samp{Runge-Kutta-4}
produces a function that takes a system state and produces a function that takes a system state and
produces a new system state. produces a new system state.
@ -8162,7 +8163,7 @@ produces a new system state.
@end example @end example
@samp{map-streams} is analogous to @samp{map}: it applies its first @samp{Map-streams} is analogous to @samp{map}: it applies its first
argument (a procedure) to all the elements of its second argument (a argument (a procedure) to all the elements of its second argument (a
stream). stream).