new option to auto-close varassign redirs; fixed some new parser error reporting issues

doc/bash.1

@@ -589,12 +589,12 @@ The
 variable may be used to specify the format of
 the time information.
 .PP
-Each command in a pipeline is executed as a separate process (i.e., in a
-subshell).
+Each command in a pipeline is executed in a \fIsubshell\fP, which is a
+separate process.
 See
 .SM
 \fBCOMMAND EXECUTION ENVIRONMENT\fP
-for a description of a subshell environment.
+for a description of subshells and a subshell environment.
 If the \fBlastpipe\fP option is enabled using the \fBshopt\fP builtin
 (see the description of \fBshopt\fP below),
 the last element of a pipeline may be run by the shell process
@@ -673,10 +673,10 @@ the rest of the command by one or more newlines, and may be followed by a
 newline in place of a semicolon.
 .TP
 (\fIlist\fP)
-\fIlist\fP is executed in a subshell environment (see
+\fIlist\fP is executed in a subshell (see
 .SM
 \fBCOMMAND EXECUTION ENVIRONMENT\fP
-below).
+below for a description of a subshell environment).
 Variable assignments and builtin
 commands that affect the shell's environment do not remain in effect
 after the command completes.  The return status is the exit status of
@@ -1278,10 +1278,7 @@ is evaluated as an arithmetic expression even if the $((...)) expansion is
 not used (see
 .B "Arithmetic Expansion"
 below).
-Word splitting is not performed, with the exception
-of \fB"$@"\fP as explained below under
-.BR "Special Parameters" .
-Pathname expansion is not performed.
+Word splitting and pathname expansion are not performed.
 Assignment statements may also appear as arguments to the
 .BR alias ,
 .BR declare ,
@@ -1435,7 +1432,7 @@ builtin command, or those set by the shell itself
 option).
 .TP
 .B $
-Expands to the process ID of the shell.  In a () subshell, it
+Expands to the process ID of the shell. In a subshell, it
 expands to the process ID of the current shell, not the
 subshell.
 .TP
@@ -3950,7 +3947,8 @@ by {\fIvarname\fP}, the value of \fIvarname\fP defines the file
 descriptor to close.
 If {\fIvarname\fP} is supplied, the redirection persists beyond
 the scope of the command, allowing the shell programmer to manage
-the file descriptor himself.
+the file descriptor's lifetime manually.
+The \fBvarredir_close\fP shell option manages this behavior.
 .PP
 In the following descriptions, if the file descriptor number is
 omitted, and the first character of the redirection operator is
@@ -4503,7 +4501,8 @@ or
 will list the function names only
 (and optionally the source file and line number, if the \fBextdebug\fP
 shell option is enabled).
-Functions may be exported so that subshells
+Functions may be exported so that child shell processes
+(those created when executing a separate shell invocation)
 automatically have them defined with the
 .B \-f
 option to the
@@ -4892,8 +4891,9 @@ to the command are set to the arguments given, if any.
 If this execution fails because the file is not in executable
 format, and the file is not a directory, it is assumed to be
 a \fIshell script\fP, a file
-containing shell commands.  A subshell is spawned to execute
-it.  This subshell reinitializes itself, so
+containing shell commands, and the shell creates a 
+to execute it.
+This subshell reinitializes itself, so
 that the effect is as if a new shell had been invoked
 to handle the script, with the exception that the locations of
 commands remembered by the parent (see
@@ -4949,8 +4949,8 @@ of \fB$$\fP, and the value of
 When a simple command other than a builtin or shell function
 is to be executed, it
 is invoked in a separate execution environment that consists of
-the following.  Unless otherwise noted, the values are inherited
-from the shell.
+the following.
+Unless otherwise noted, the values are inherited from the shell.
 .if n .sp 1
 .IP \(bu
 the shell's open files, plus any modifications and additions specified
@@ -4969,6 +4969,8 @@ shell's parent, and traps ignored by the shell are ignored
 A command invoked in this separate environment cannot affect the
 shell's execution environment.
 .PP
+A \fIsubshell\fP is a copy of the shell process.
+.PP
 Command substitution, commands grouped with parentheses,
 and asynchronous commands are invoked in a
 subshell environment that is a duplicate of the shell environment,
@@ -10398,6 +10400,13 @@ If set, the
 to find the directory containing the file supplied as an argument.
 This option is enabled by default.
 .TP 8
+.B varredir_close
+If set, the shell automatically closes file descriptors assigned using the
+\fI{varname}\fP redirection syntax (see
+.SM
+.B REDIRECTION
+above) instead of leaving them open when the command completes.
+.TP 8
 .B xpg_echo
 If set, the \fBecho\fP builtin expands backslash-escape sequences
 by default.