commit 321cb6a38ca9d5e6f457b293607a89155ecfd17a
parent ef78e027d1a629a8dfb33b72e9cc250cb5607ba9
Author: Wolfgang Corcoran-Mathe <wcm@sigwinch.xyz>
Date: Wed, 31 Jan 2024 21:12:40 -0500
Reflow.
Diffstat:
1 file changed, 76 insertions(+), 68 deletions(-)
diff --git a/doc/r7rs-small/r7rs-small.texinfo b/doc/r7rs-small/r7rs-small.texinfo
@@ -1749,20 +1749,19 @@ a core set of features is given in appendix B.
@node Binding constructs
@subsection Binding constructs
-The binding constructs @code{let}, @code{let*}, @code{letrec}, @code{letrec*},
-@code{let-values}, and @code{let*-values}
-give Scheme a block structure, like Algol 60. The syntax of the first four
-constructs is identical, but they differ in the regions they establish
-for their variable bindings. In a @code{let} expression, the initial
-values are computed before any of the variables become bound; in a
-@code{let*} expression, the bindings and evaluations are performed
-sequentially; while in @code{letrec} and @code{letrec*} expressions,
-all the bindings are in
-effect while their initial values are being computed, thus allowing
-mutually recursive definitions.
-The @code{let-values} and @code{let*-values} constructs are analogous to @code{let} and @code{let*}
-respectively, but are designed to handle multiple-valued expressions, binding
-different identifiers to the returned values.
+The binding constructs @code{let}, @code{let*}, @code{letrec},
+@code{letrec*}, @code{let-values}, and @code{let*-values} give Scheme a
+block structure, like Algol 60. The syntax of the first four constructs is
+identical, but they differ in the regions they establish for their variable
+bindings. In a @code{let} expression, the initial values are computed before
+any of the variables become bound; in a @code{let*} expression, the bindings
+and evaluations are performed sequentially; while in @code{letrec} and
+@code{letrec*} expressions, all the bindings are in effect while their
+initial values are being computed, thus allowing mutually recursive
+definitions. The @code{let-values} and @code{let*-values} constructs are
+analogous to @code{let} and @code{let*} respectively, but are designed to
+handle multiple-valued expressions, binding different identifiers to the
+returned values.
@deffn syntax let @svar{bindings} @svar{body}
@@ -1773,14 +1772,15 @@ Syntax: @svar{Bindings} has the form
@end display
where each @svar{init} is an expression, and @svar{body} is a sequence of
-zero or more definitions followed by a sequence of one or more expressions as described
-in @ref{Expressions}. It is an error for a @svar{variable} to appear more than once in the list of
-variables being bound.
+zero or more definitions followed by a sequence of one or more expressions
+as described in @ref{Expressions}. It is an error for a @svar{variable} to
+appear more than once in the list of variables being bound.
-Semantics: The @svar{init}s are evaluated in the current environment (in some unspecified
-order), the @svar{variable}s are bound to fresh locations holding the results, the @svar{body} is
-evaluated in the extended environment, and the values of the last expression of @svar{body}
-are returned. Each binding of a @svar{variable} has @svar{body} as its region.
+Semantics: The @svar{init}s are evaluated in the current environment (in
+some unspecified order), the @svar{variable}s are bound to fresh locations
+holding the results, the @svar{body} is evaluated in the extended
+environment, and the values of the last expression of @svar{body} are
+returned. Each binding of a @svar{variable} has @svar{body} as its region.
@example
@@ -1808,13 +1808,12 @@ Syntax: @svar{Bindings} has the form
and @svar{body} is a sequence of zero or more definitions followed by
one or more expressions as described in @ref{Expressions}.
-Semantics:
-The @code{let*} binding construct is similar to @code{let}, but the bindings are performed
-sequentially from left to right, and the region of a binding indicated
-by @code{(}@svar{variable} @svar{init}@code{)} is that part of the @code{let*}
-expression to the right of the binding. Thus the second binding is done
-in an environment in which the first binding is visible, and so on.
-The @svar{variable}s need not be distinct.
+Semantics: The @code{let*} binding construct is similar to @code{let}, but
+the bindings are performed sequentially from left to right, and the region
+of a binding indicated by @code{(}@svar{variable} @svar{init}@code{)} is
+that part of the @code{let*} expression to the right of the binding. Thus
+the second binding is done in an environment in which the first binding is
+visible, and so on. The @svar{variable}s need not be distinct.
@example
@@ -1834,16 +1833,19 @@ Syntax: @svar{Bindings} has the form
@code{((}@svar{variable@sub{1}} @svar{init@sub{1}}@code{)} @dots{}@code{)},
@end display
-and @svar{body} is a sequence of zero or more definitions followed by
-one or more expressions as described in @ref{Expressions}. It is an error for a @svar{variable} to
-appear more than once in the list of variables being bound.
+and @svar{body} is a sequence of zero or more definitions followed by one or
+more expressions as described in @ref{Expressions}. It is an error for a
+@svar{variable} to appear more than once in the list of variables being
+bound.
-Semantics: The @svar{variable}s are bound to fresh locations holding unspecified values, the
-@svar{init}s are evaluated in the resulting environment (in some unspecified order), each
-@svar{variable} is assigned to the result of the corresponding @svar{init}, the @svar{body} is evaluated in
-the resulting environment, and the values of the last expression in @svar{body} are returned.
-Each binding of a @svar{variable} has the entire letrec expression as its region, making it
-possible to define mutually recursive procedures.
+Semantics: The @svar{variable}s are bound to fresh locations holding
+unspecified values, the @svar{init}s are evaluated in the resulting
+environment (in some unspecified order), each @svar{variable} is assigned to
+the result of the corresponding @svar{init}, the @svar{body} is evaluated in
+the resulting environment, and the values of the last expression in
+@svar{body} are returned. Each binding of a @svar{variable} has the entire
+letrec expression as its region, making it possible to define mutually
+recursive procedures.
@example
@@ -1862,11 +1864,13 @@ possible to define mutually recursive procedures.
@end example
-One restriction on @code{letrec} is very important: if it is not possible to evaluate each @svar{init}
-without assigning or referring to the value of any @svar{variable}, it is an error. The restriction
-is necessary because @code{letrec} is defined in terms of a procedure call where a @code{lambda}
-expression binds the @svar{variable}s to the values of the @svar{init}s. In the most common uses of
-@code{letrec}, all the @svar{init}s are @code{lambda} expressions and the restriction is satisfied automatically.
+One restriction on @code{letrec} is very important: if it is not possible to
+evaluate each @svar{init} without assigning or referring to the value of any
+@svar{variable}, it is an error. The restriction is necessary because
+@code{letrec} is defined in terms of a procedure call where a @code{lambda}
+expression binds the @svar{variable}s to the values of the @svar{init}s. In
+the most common uses of @code{letrec}, all the @svar{init}s are
+@code{lambda} expressions and the restriction is satisfied automatically.
@end deffn
@deffn syntax letrec* @svar{bindings} @svar{body}
@@ -1877,20 +1881,24 @@ Syntax: @svar{Bindings} has the form
@code{((}@svar{variable@sub{1}} @svar{init@sub{1}}@code{)} @dots{}@code{)},
@end display
-and @svar{body}is a sequence of zero or more definitions followed by
-one or more expressions as described in @ref{Expressions}. It is an error for a @svar{variable} to
-appear more than once in the list of variables being bound.
-
-Semantics: The @svar{variable}s are bound to fresh locations, each @svar{variable} is assigned in
-left-to-right order to the result of evaluating the corresponding @svar{init} (interleaving
-evaluations and assignments), the @svar{body} is evaluated in the resulting environment, and
-the values of the last expression in @svar{body} are returned. Despite the left-to-right
-evaluation and assignment order, each binding of a @svar{variable} has the entire @code{letrec*}
-expression as its region, making it possible to define mutually recursive procedures.
-
-If it is not possible to evaluate each @svar{init} without assigning or referring to the value of
-the corresponding @svar{variable} or the @svar{variable} of any of the bindings that follow it in
-@svar{bindings}, it is an error. Another restriction is that it is an error to invoke the
+and @svar{body}is a sequence of zero or more definitions followed by one or
+more expressions as described in @ref{Expressions}. It is an error for a
+@svar{variable} to appear more than once in the list of variables being
+bound.
+
+Semantics: The @svar{variable}s are bound to fresh locations, each
+@svar{variable} is assigned in left-to-right order to the result of
+evaluating the corresponding @svar{init} (interleaving evaluations and
+assignments), the @svar{body} is evaluated in the resulting environment, and
+the values of the last expression in @svar{body} are returned. Despite the
+left-to-right evaluation and assignment order, each binding of a
+@svar{variable} has the entire @code{letrec*} expression as its region,
+making it possible to define mutually recursive procedures.
+
+If it is not possible to evaluate each @svar{init} without assigning or
+referring to the value of the corresponding @svar{variable} or the
+@svar{variable} of any of the bindings that follow it in @svar{bindings}, it
+is an error. Another restriction is that it is an error to invoke the
continuation of an @svar{init} more than once.
@example
@@ -1917,8 +1925,8 @@ continuation of an @svar{init} more than once.
@end example
-Evaluating @code{(means '(3 (1 4)))} returns three values: 8/3, 2.28942848510666 (approximately),
-and 36/19.
+Evaluating @code{(means '(3 (1 4)))} returns three values: 8/3,
+2.28942848510666 (approximately), and 36/19.
@end deffn
@deffn syntax let-values @svar{mv binding spec} @svar{body}
@@ -1945,8 +1953,8 @@ the extended environment, and the values of the last expression of
@svar{body} are returned. Each binding of a @svar{variable} has
@svar{body} as its region.
-It is an error if the @svar{formals} do not match the number of values returned by the
-corresponding @svar{init}.
+It is an error if the @svar{formals} do not match the number of values
+returned by the corresponding @svar{init}.
@example
@@ -1964,16 +1972,16 @@ Syntax: @svar{Mv binding spec} has the form
@code{((}@svar{formals} @svar{init}@code{)} @dots{}@code{)},
@end display
-and @svar{body} is a sequence of zero or more definitions followed by
-one or more expressions as described in @ref{Expressions}. In each @svar{formals}, it is an error if
-any variable appears more than once.
+and @svar{body} is a sequence of zero or more definitions followed by one or
+more expressions as described in @ref{Expressions}. In each @svar{formals},
+it is an error if any variable appears more than once.
The @code{let*-values} construct is similar to @code{let-values}, but the
-@svar{init}s are evaluated and bindings created sequentially from
-left to right, with the region of the bindings of each @svar{formals}
-including the @svar{init}s to its right as well as @svar{body}. Thus the
-second @svar{init} is evaluated in an environment in which the first
-set of bindings is visible and initialized, and so on.
+@svar{init}s are evaluated and bindings created sequentially from left to
+right, with the region of the bindings of each @svar{formals} including the
+@svar{init}s to its right as well as @svar{body}. Thus the second
+@svar{init} is evaluated in an environment in which the first set of
+bindings is visible and initialized, and so on.
@example
