commit f2937728cc4b938a7ba99da67b0ac336c495363f
parent cc4001143d7de4e03485c1c8f5e8b3f4f6e0a184
Author: Wolfgang Corcoran-Mathe <wcm@sigwinch.xyz>
Date: Fri, 2 Feb 2024 13:14:17 -0500
Fix doubled @var macros.
Oops.
Diffstat:
1 file changed, 64 insertions(+), 62 deletions(-)
diff --git a/doc/r7rs-small/procedures/equivalence-predicates.texinfo b/doc/r7rs-small/procedures/equivalence-predicates.texinfo
@@ -1,20 +1,21 @@
@node Equivalence predicates
@section Equivalence predicates
-A @dfn{predicate} is a procedure that always returns a boolean
-value (@code{#t} or @code{#f}). An @dfn{equivalence predicate} is
-the computational analogue of a mathematical equivalence relation; it is
+A @dfn{predicate} is a procedure that always returns a boolean value
+(@code{#t} or @code{#f}). An @dfn{equivalence predicate} is the
+computational analogue of a mathematical equivalence relation; it is
symmetric, reflexive, and transitive. Of the equivalence predicates
described in this section, @code{eq?} is the finest or most
discriminating, @code{equal?} is the coarsest, and @code{eqv?} is
-slightly less discriminating than @code{eq?}.
+slightly less discriminating than @code{eq?}.
@deffn procedure eqv? @var{obj@sub{1}} @var{obj@sub{2}}
-The @code{eqv?} procedure defines a useful equivalence relation on objects. Briefly, it returns @code{#t}
-if
-@var{@var{obj@sub{1}}} and @var{@var{obj@sub{2}}} are normally regarded as the same object. This relation is left slightly open to
-interpretation, but the following partial specification of @code{eqv?} holds for all implementations
+The @code{eqv?} procedure defines a useful equivalence relation on
+objects. Briefly, it returns @code{#t} if @var{obj@sub{1}} and
+@var{obj@sub{2}} are normally regarded as the same object. This
+relation is left slightly open to interpretation, but the following
+partial specification of @code{eqv?} holds for all implementations
of Scheme.
The @code{eqv?} procedure returns @code{#t} if:
@@ -22,42 +23,43 @@ The @code{eqv?} procedure returns @code{#t} if:
@itemize
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both @code{#t} or both @code{#f}.
+@var{obj@sub{1}} and @var{obj@sub{2}} are both @code{#t} or
+both @code{#f}.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both symbols and are the same symbol according to the @code{symbol=?} procedure
- (@ref{Symbols}).
+@var{obj@sub{1}} and @var{obj@sub{2}} are both symbols and
+are the same symbol according to the @code{symbol=?} procedure
+(@ref{Symbols}).
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both exact numbers and are numerically equal (in the sense of @code{=}).
+@var{obj@sub{1}} and @var{obj@sub{2}} are both exact
+numbers and are numerically equal (in the sense of @code{=}).
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both inexact numbers such that they are numerically equal (in the sense of @code{=})
- and they yield the same results (in the sense of @code{eqv?}) when passed as arguments to any
- other procedure that can be defined as a finite composition of Scheme's standard
- arithmetic procedures, provided it does not result in a NaN value.
+@var{obj@sub{1}} and @var{obj@sub{2}} are both inexact
+numbers such that they are numerically equal (in the sense of @code{=})
+and they yield the same results (in the sense of @code{eqv?}) when
+passed as arguments to any other procedure that can be defined as a
+finite composition of Scheme's standard arithmetic procedures, provided
+it does not result in a NaN value.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both characters and are the same character according to the @code{char=?} procedure
- (@ref{Characters}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are both characters and are the same character according to the @code{char=?} procedure
+(@ref{Characters}).
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both the empty list.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are both the empty list.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are pairs, vectors, bytevectors, records, or strings that denote the same location in
- the store (@ref{Storage model}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are pairs, vectors, bytevectors, records, or strings that denote the same location in
+the store (@ref{Storage model}).
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are procedures whose location tags are equal (@ref{Procedures}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are procedures whose location tags are equal (@ref{Procedures}).
@end itemize
@@ -66,55 +68,55 @@ The @code{eqv?} procedure returns @code{#f} if:
@itemize
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are of different types (@ref{Disjointness of types}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are of different types (@ref{Disjointness of types}).
@item
one of
- @var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} is @code{#t} but the other is @code{#f}.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} is @code{#t} but the other is @code{#f}.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are symbols but are not the same symbol according to the @code{symbol=?} procedure
- (@ref{Symbols}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are symbols but are not the same symbol according to the @code{symbol=?} procedure
+(@ref{Symbols}).
@item
one of
- @var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} is an exact number but the other is an inexact number.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} is an exact number but the other is an inexact number.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both exact numbers and are numerically unequal (in the sense of @code{=}).
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are both exact numbers and are numerically unequal (in the sense of @code{=}).
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are both inexact numbers such that either they are numerically unequal (in the
- sense of @code{=}), or they do not yield the same results (in the sense of @code{eqv?}) when passed as
- arguments to any other procedure that can be defined as a finite composition of
- Scheme's standard arithmetic procedures, provided it does not result in a NaN value. As
- an exception, the behavior of @code{eqv?} is unspecified when both
- @var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are NaN.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are both inexact numbers such that either they are numerically unequal (in the
+sense of @code{=}), or they do not yield the same results (in the sense of @code{eqv?}) when passed as
+arguments to any other procedure that can be defined as a finite composition of
+Scheme's standard arithmetic procedures, provided it does not result in a NaN value. As
+an exception, the behavior of @code{eqv?} is unspecified when both
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are NaN.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are characters for which the @code{char=?} procedure returns @code{#f}.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are characters for which the @code{char=?} procedure returns @code{#f}.
@item
one of
- @var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} is the empty list but the other is not.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} is the empty list but the other is not.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are pairs, vectors, bytevectors, records, or strings that denote distinct locations.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are pairs, vectors, bytevectors, records, or strings that denote distinct locations.
@item
-@var{@var{obj@sub{1}}} and
- @var{@var{obj@sub{2}}} are procedures that would behave differently (return different values or have
- different side effects) for some arguments.
+@var{obj@sub{1}} and
+@var{obj@sub{2}} are procedures that would behave differently (return different values or have
+different side effects) for some arguments.
@end itemize
@@ -250,10 +252,10 @@ differently from @code{eqv?}.
@end example
Rationale: It will usually be possible to implement @code{eq?} much more efficiently than
- @code{eqv?}, for example, as a simple pointer comparison instead of as some more
- complicated operation. One reason is that it is not always possible to compute @code{eqv?}
- of two numbers in constant time, whereas @code{eq?} implemented as pointer comparison
- will always finish in constant time.
+@code{eqv?}, for example, as a simple pointer comparison instead of as some more
+complicated operation. One reason is that it is not always possible to compute @code{eqv?}
+of two numbers in constant time, whereas @code{eq?} implemented as pointer comparison
+will always finish in constant time.
@end deffn
