[PATCH] More correctly describe the scope of variables

[Jouke Witteveen]

* NEWS: Use "local" instead of the incorrect "lexically-scoped".
* doc/make.texi: Refer to let/foreach variables as local variables.
---
This is an erratum on the addition of $(let ...). During an early review
of $(let ...), thutt cautioned that it did not implement "full semantic
scoping" [sic]. While I did not understand fully what they meant by
that, I countered that it was not intended to determine a scope based on
for example which file a definition of a rule occurred in, but simply by
the parentheses delimiting the let expression. Only in that sense was it
lexical scoping. Technically, make variables are dynamically scoped.

This patch replaces "lexically scoped" not by "dynamically scoped", but
by "local", since that is the whole point after all. It also includes
variables with local scope (from let and foreach) in several other
places where variables are discussed, and makes explicit that variables
in make are dynamically scoped.

 NEWS          |  4 ++--
 doc/make.texi | 21 +++++++++++++++------
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/NEWS b/NEWS
index 5d71488..5356260 100644
--- a/NEWS
+++ b/NEWS
@@ -35,8 +35,8 @@ 
https://sv.gnu.org/bugs/index.php?group=make&report_id=111&fix_release_id=109&se
   The configure script should verify the compiler has these features.
 
 * New feature: The $(let ...) function
-  This function allows user-defined functions to provide a lexically-scoped
-  set of variables: values can be assigned to these variables from within the
+  This function allows user-defined functions to define a set of local
+  variables: values can be assigned to these variables from within the
   user-defined function and they will not impact global variable assignments.
   Implementation provided by Jouke Witteveen <j.witteveen@gmail.com>
 
diff --git a/doc/make.texi b/doc/make.texi
index fe64ec2..d7891c9 100644
--- a/doc/make.texi
+++ b/doc/make.texi
@@ -276,7 +276,7 @@ Functions for Transforming Text
 * Text Functions::              General-purpose text manipulation functions.
 * File Name Functions::         Functions for manipulating file names.
 * Conditional Functions::       Functions that implement conditions.
-* Let Function::                Lexically scoped variables.
+* Let Function::                Local variables.
 * Foreach Function::            Repeat some text with controlled variation.
 * File Function::               Write text to a file.
 * Call Function::               Expand a user-defined function.
@@ -5204,7 +5204,9 @@ variables are called @dfn{macros}.)
 Variables and functions in all parts of a makefile are expanded when
 read, except for in recipes, the right-hand sides of variable
 definitions using @samp{=}, and the bodies of variable definitions
-using the @code{define} directive.@refill
+using the @code{define} directive.  The value a variable expands to is
+that of its most recent definition at the time of expansion.  In other
+words, variables are dynamically scoped.
 
 Variables can represent lists of file names, options to pass to compilers,
 programs to run, directories to look in for source files, directories to
@@ -5792,6 +5794,11 @@ You can specify a value in the makefile, either
 with an assignment (@pxref{Setting, ,Setting Variables}) or with a
 verbatim definition (@pxref{Multi-Line, ,Defining Multi-Line 
Variables}).@refill
 
+@item
+You can specify a short-lived value with the @code{let} function
+(@pxref{Let Function}) or with the @code{foreach} function
+(@pxref{Foreach Function}).
+
 @item
 Variables in the environment become @code{make} variables.
 @xref{Environment, ,Variables from the Environment}.
@@ -6274,10 +6281,12 @@ the Shell}.@refill
 
 Variable values in @code{make} are usually global; that is, they are the
 same regardless of where they are evaluated (unless they're reset, of
-course).  One exception to that is automatic variables
+course).  Exceptions to that are variables defined with the @code{let}
+function (@pxref{Let Function}) or the @code{foreach} function
+(@pxref{Foreach Function}, and automatic variables
 (@pxref{Automatic Variables}).
 
-The other exception is @dfn{target-specific variable values}.  This
+Another exception are @dfn{target-specific variable values}.  This
 feature allows you to define different values for the same variable,
 based on the target that @code{make} is currently building.  As with
 automatic variables, these values are only available within the context
@@ -7039,7 +7048,7 @@ be substituted.
 * Text Functions::              General-purpose text manipulation functions.
 * File Name Functions::         Functions for manipulating file names.
 * Conditional Functions::       Functions that implement conditions.
-* Let Function::                Lexically scoped variables.
+* Let Function::                Local variables.
 * Foreach Function::            Repeat some text with controlled variation.
 * File Function::               Write text to a file.
 * Call Function::               Expand a user-defined function.
@@ -7696,7 +7705,7 @@ the result of the expansion is the expansion of the last 
argument.
 @node Let Function, Foreach Function, Conditional Functions, Functions
 @section The @code{let} Function
 @findex let
-@cindex variables, lexically scoped
+@cindex variables, local
 
 The @code{let} function provides a means to limit the scope of a
 variable.  The assignment of the named variables in a @code{let}
-- 
2.29.2