bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Jim Porter]

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The Eshell manual isn't as thorough as it could be about how users 
should invoke commands. While there's a reasonable amount of 
documentation about the details, it never directly describes how to run 
a simple command.

Attached is a patch to remedy this. I also corrected the documentation 
about how Eshell picks what command to run in command form; previously, 
it stated that ordinary Lisp functions had higher priority than external 
commands, which isn't actually the case (unless you set 
'eshell-prefer-lisp-functions').

Since this is purely a documentation change, I'd like to merge this to 
the Emacs 29 branch.

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From d0e4b94623b5840a212c97c75b1641dbbbff77ea Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Sun, 15 Jan 2023 18:35:31 -0800
Subject: [PATCH] Add more detail about how to invoke Eshell commands

* doc/misc/eshell.texi (Commands): Move explanation about kernel
functions to here.
(Invocation): Describe command form and Lisp form.  Fix documentation
about priority of commands in command form.
---
 doc/misc/eshell.texi | 93 +++++++++++++++++++++++++++++++++-----------
 1 file changed, 70 insertions(+), 23 deletions(-)

diff --git a/doc/misc/eshell.texi b/doc/misc/eshell.texi
index fc7d52eb711..b5444741b66 100644
--- a/doc/misc/eshell.texi
+++ b/doc/misc/eshell.texi
@@ -193,6 +193,12 @@ Commands
 chapter covers command invocations in Eshell, including the command
 history and invoking commands in a script file.
 
+Unlike regular system shells, Eshell never invokes kernel functions
+directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
+available in the Emacs Lisp library.  It does this by transforming the
+input line into a callable Lisp form.@footnote{To see the Lisp form
+that will be invoked, type: @samp{eshell-parse-command 'echo hello'}}
+
 @menu
 * Invocation::
 * Arguments::
@@ -207,23 +213,16 @@ Commands
 
 @node Invocation
 @section Invocation
-Unlike regular system shells, Eshell never invokes kernel functions
-directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
-available in the Emacs Lisp library.  It does this by transforming the
-input line into a callable Lisp form.@footnote{To see the Lisp form that will be invoked, type: @samp{eshell-parse-command "echo hello"}}
+Eshell is both a command shell and an Emacs Lisp @acronym{REPL}.  As a
+result, you can invoke commands in two different ways: in @dfn{command
+form} or in @dfn{lisp form}.
 
-The command can be either an Elisp function or an external command.
-Eshell looks first for an alias (@pxref{Aliases}) with the same name as the
-command, then a built-in (@pxref{Built-ins}) or a function with the
-same name; if there is no match, it then tries to execute it as an
-external command.
-
-The semicolon (@code{;}) can be used to separate multiple command
-invocations on a single line.  You can also separate commands with
-@code{&&} or @code{||}. When using @code{&&}, Eshell will execute the
-second command only if the first succeeds (i.e.@: has an exit
-status of 0); with @code{||}, Eshell will execute the second command
-only if the first fails.
+You can use the semicolon (@code{;}) to separate multiple command
+invocations on a single line, executing each in turn.  You can also
+separate commands with @code{&&} or @code{||}. When using @code{&&},
+Eshell will execute the second command only if the first succeeds
+(i.e.@: has an exit status of 0); with @code{||}, Eshell will execute
+the second command only if the first fails.
 
 A command invocation followed by an ampersand (@code{&}) will be run
 in the background.  Eshell has no job control, so you can not suspend
@@ -232,12 +231,64 @@ Invocation
 can be controlled the same way as any other background process in
 Emacs.
 
+@subsection Command form
+Command form looks much the same as in other shells.  A command
+consists of arguments separated by spaces; the first argument is the
+command to run, with any subsequent arguments being passed to that
+command.
+
+@example
+~ $ echo hello
+hello
+@end example
+
+The command can be either an Elisp function or an external command.
+Eshell looks for the command in the following order:
+
+@enumerate
+@item
+As a command alias (@pxref{Aliases})
+
+@item
+As a built-in command (@pxref{Built-ins})
+
+@item
+As an external program
+
+@item
+As an ordinary Lisp function
+@end enumerate
+
+@vindex eshell-prefer-lisp-functions
+If you would prefer to use ordinary Lisp functions over external
+programs, set the option @code{eshell-prefer-lisp-functions} to
+@code{t}.
+
+@subsection Lisp form
+Lisp form looks like ordinary Emacs Lisp code, because that's what it
+is.  As a result, you can use any syntax normally available to an
+Emacs Lisp program (@pxref{Top, , , elisp, The Emacs Lisp Reference
+Manual}).
+
+@example
+~ $ (format "hello, %s" user-login-name)
+hello, user
+@end example
+
+In addition, you can @emph{combine} command forms and Lisp forms
+together into single statements, letting you use whatever form is the
+most convenient for expressing your intentions.
+
+@example
+~ $ ls *.patch > (format-time-string "%F.log")
+@end example
+
 @node Arguments
 @section Arguments
-Ordinarily, command arguments are parsed by Eshell as either strings
+Ordinarily, Eshell parses arguments in command form as either strings
 or numbers, depending on what the parser thinks they look like.  To
-specify an argument of some other data type, you can use an
-@ref{Dollars Expansion, Elisp expression}:
+specify an argument of some other data type, you can use a
+@ref{Invocation, Lisp form}:
 
 @example
 ~ $ echo (list 1 2 3)
@@ -354,10 +405,6 @@ Built-ins
 sudo is an alias, defined as "*sudo $@@*"
 @end example
 
-@vindex eshell-prefer-lisp-functions
-If you would prefer to use the built-in commands instead of the external
-commands, set @code{eshell-prefer-lisp-functions} to @code{t}.
-
 Some of the built-in commands have different behavior from their
 external counterparts, and some have no external counterpart.  Most of
 these will print a usage message when given the @code{--help} option.
-- 
2.25.1

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Jim Porter]

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Oops. Forgot to save the file, so I missed part of my update in the 
patch. Fixed here.

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From e2e9e3257cdd5fde1256d8a0937ca7b2c6800588 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Sun, 15 Jan 2023 18:35:31 -0800
Subject: [PATCH] Add more detail about how to invoke Eshell commands

* doc/misc/eshell.texi (Commands): Move explanation about kernel
functions to here.
(Invocation): Describe command form and Lisp form.  Fix documentation
about priority of commands in command form.
---
 doc/misc/eshell.texi | 103 +++++++++++++++++++++++++++++++++----------
 1 file changed, 80 insertions(+), 23 deletions(-)

diff --git a/doc/misc/eshell.texi b/doc/misc/eshell.texi
index fc7d52eb711..2e8703059f1 100644
--- a/doc/misc/eshell.texi
+++ b/doc/misc/eshell.texi
@@ -193,6 +193,12 @@ Commands
 chapter covers command invocations in Eshell, including the command
 history and invoking commands in a script file.
 
+Unlike regular system shells, Eshell never invokes kernel functions
+directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
+available in the Emacs Lisp library.  It does this by transforming the
+input line into a callable Lisp form.@footnote{To see the Lisp form
+that will be invoked, type: @samp{eshell-parse-command 'echo hello'}}
+
 @menu
 * Invocation::
 * Arguments::
@@ -207,23 +213,16 @@ Commands
 
 @node Invocation
 @section Invocation
-Unlike regular system shells, Eshell never invokes kernel functions
-directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
-available in the Emacs Lisp library.  It does this by transforming the
-input line into a callable Lisp form.@footnote{To see the Lisp form that will be invoked, type: @samp{eshell-parse-command "echo hello"}}
+Eshell is both a command shell and an Emacs Lisp @acronym{REPL}.  As a
+result, you can invoke commands in two different ways: in @dfn{command
+form} or in @dfn{lisp form}.
 
-The command can be either an Elisp function or an external command.
-Eshell looks first for an alias (@pxref{Aliases}) with the same name as the
-command, then a built-in (@pxref{Built-ins}) or a function with the
-same name; if there is no match, it then tries to execute it as an
-external command.
-
-The semicolon (@code{;}) can be used to separate multiple command
-invocations on a single line.  You can also separate commands with
-@code{&&} or @code{||}. When using @code{&&}, Eshell will execute the
-second command only if the first succeeds (i.e.@: has an exit
-status of 0); with @code{||}, Eshell will execute the second command
-only if the first fails.
+You can use the semicolon (@code{;}) to separate multiple command
+invocations on a single line, executing each in turn.  You can also
+separate commands with @code{&&} or @code{||}. When using @code{&&},
+Eshell will execute the second command only if the first succeeds
+(i.e.@: has an exit status of 0); with @code{||}, Eshell will execute
+the second command only if the first fails.
 
 A command invocation followed by an ampersand (@code{&}) will be run
 in the background.  Eshell has no job control, so you can not suspend
@@ -232,12 +231,74 @@ Invocation
 can be controlled the same way as any other background process in
 Emacs.
 
+@subsection Command form
+Command form looks much the same as in other shells.  A command
+consists of arguments separated by spaces; the first argument is the
+command to run, with any subsequent arguments being passed to that
+command.
+
+@example
+~ $ echo hello
+hello
+@end example
+
+The command can be either an Elisp function or an external command.
+Eshell looks for the command in the following order:
+
+@enumerate
+@item
+As a command alias (@pxref{Aliases})
+
+@item
+As a built-in command (@pxref{Built-ins})
+
+@item
+As an external program
+
+@item
+As an ordinary Lisp function
+@end enumerate
+
+@vindex eshell-prefer-lisp-functions
+If you would prefer to use ordinary Lisp functions over external
+programs, set the option @code{eshell-prefer-lisp-functions} to
+@code{t}.
+
+You can also group command forms together into a subcommand with curly
+braces (@code{@{@}}).  This lets you use the output of a subcommand as
+an argument to another command, or within control flow statements
+(@pxref{Control Flow}).
+
+@example
+~ $ echo @{echo hello; echo there@}
+hellothere
+@end example
+
+@subsection Lisp form
+Lisp form looks like ordinary Emacs Lisp code, because that's what it
+is.  As a result, you can use any syntax normally available to an
+Emacs Lisp program (@pxref{Top, , , elisp, The Emacs Lisp Reference
+Manual}).
+
+@example
+~ $ (format "hello, %s" user-login-name)
+hello, user
+@end example
+
+In addition, you can @emph{combine} command forms and Lisp forms
+together into single statements, letting you use whatever form is the
+most convenient for expressing your intentions.
+
+@example
+~ $ ls *.patch > (format-time-string "%F.log")
+@end example
+
 @node Arguments
 @section Arguments
-Ordinarily, command arguments are parsed by Eshell as either strings
+Ordinarily, Eshell parses arguments in command form as either strings
 or numbers, depending on what the parser thinks they look like.  To
-specify an argument of some other data type, you can use an
-@ref{Dollars Expansion, Elisp expression}:
+specify an argument of some other data type, you can use a
+@ref{Invocation, Lisp form}:
 
 @example
 ~ $ echo (list 1 2 3)
@@ -354,10 +415,6 @@ Built-ins
 sudo is an alias, defined as "*sudo $@@*"
 @end example
 
-@vindex eshell-prefer-lisp-functions
-If you would prefer to use the built-in commands instead of the external
-commands, set @code{eshell-prefer-lisp-functions} to @code{t}.
-
 Some of the built-in commands have different behavior from their
 external counterparts, and some have no external counterpart.  Most of
 these will print a usage message when given the @code{--help} option.
-- 
2.25.1

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Eli Zaretskii]

> Date: Sun, 15 Jan 2023 18:51:25 -0800
> From: Jim Porter <jporterbugs@gmail.com>
> 
> The Eshell manual isn't as thorough as it could be about how users 
> should invoke commands. While there's a reasonable amount of 
> documentation about the details, it never directly describes how to run 
> a simple command.
> 
> Attached is a patch to remedy this. I also corrected the documentation 
> about how Eshell picks what command to run in command form; previously, 
> it stated that ordinary Lisp functions had higher priority than external 
> commands, which isn't actually the case (unless you set 
> 'eshell-prefer-lisp-functions').

Thanks.

> Since this is purely a documentation change, I'd like to merge this to 
> the Emacs 29 branch.

That's fine.

> +Unlike regular system shells, Eshell never invokes kernel functions
> +directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
> +available in the Emacs Lisp library.  It does this by transforming the
> +input line into a callable Lisp form.@footnote{To see the Lisp form
> +that will be invoked, type: @samp{eshell-parse-command 'echo hello'}}

This should use the @kbd markup, like any command the user should
type.  I also suggest to say explicitly that you mean to type this at
the Eshell prompt, as it wasn't clear when I read it.

> +The command can be either an Elisp function or an external command.
> +Eshell looks for the command in the following order:

Here I would add a few useful index entries

  @cindex order of looking for commands
  @cindex command look up, order

> +@vindex eshell-prefer-lisp-functions
> +If you would prefer to use ordinary Lisp functions over external
> +programs, set the option @code{eshell-prefer-lisp-functions} to
> +@code{t}.

I'm guessing this swaps the order of the two last candidates, but the
text doesn't say that explicitly for some reason.  Just saying
"prefer" is not enough when you have more than 2 candidates.

> +In addition, you can @emph{combine} command forms and Lisp forms
> +together into single statements, letting you use whatever form is the
> +most convenient for expressing your intentions.
> +
> +@example
> +~ $ ls *.patch > (format-time-string "%F.log")
> +@end example

Either explain here the meaning of redirecting into a Lisp form, or
add a cross-reference to where it is explained in detail.

> +specify an argument of some other data type, you can use a
> +@ref{Invocation, Lisp form}:

This kind of cross-references is usually a bad idea in Texinfo: it
looks nifty in HTML, but reads awkwardly in all other formats.  It is
better to use the slightly wordier alternative:

  specify an argument of some other data type, you can use a Lisp form
  (@pxref{Invocation}):

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Jim Porter]

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On 1/16/2023 5:38 AM, Eli Zaretskii wrote:
> Thanks.

Thanks for the useful feedback as always.

>> +Unlike regular system shells, Eshell never invokes kernel functions
>> +directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
>> +available in the Emacs Lisp library.  It does this by transforming the
>> +input line into a callable Lisp form.@footnote{To see the Lisp form
>> +that will be invoked, type: @samp{eshell-parse-command 'echo hello'}}
> 
> This should use the @kbd markup, like any command the user should
> type.  I also suggest to say explicitly that you mean to type this at
> the Eshell prompt, as it wasn't clear when I read it.

Fixed.

>> +The command can be either an Elisp function or an external command.
>> +Eshell looks for the command in the following order:
> 
> Here I would add a few useful index entries
> 
>    @cindex order of looking for commands
>    @cindex command look up, order

Done.

>> +@vindex eshell-prefer-lisp-functions
>> +If you would prefer to use ordinary Lisp functions over external
>> +programs, set the option @code{eshell-prefer-lisp-functions} to
>> +@code{t}.
> 
> I'm guessing this swaps the order of the two last candidates, but the
> text doesn't say that explicitly for some reason.  Just saying
> "prefer" is not enough when you have more than 2 candidates.

Good point. I added an extra sentence explicitly stating that the last 
two items are swapped in priority.

>> +In addition, you can @emph{combine} command forms and Lisp forms
>> +together into single statements, letting you use whatever form is the
>> +most convenient for expressing your intentions.
>> +
>> +@example
>> +~ $ ls *.patch > (format-time-string "%F.log")
>> +@end example
> 
> Either explain here the meaning of redirecting into a Lisp form, or
> add a cross-reference to where it is explained in detail.

Done both. I've explained what the command does as well as 
cross-referenced the globbing and redirection sections.

>> +specify an argument of some other data type, you can use a
>> +@ref{Invocation, Lisp form}:
> 
> This kind of cross-references is usually a bad idea in Texinfo: it
> looks nifty in HTML, but reads awkwardly in all other formats.  It is
> better to use the slightly wordier alternative:
> 
>    specify an argument of some other data type, you can use a Lisp form
>    (@pxref{Invocation}):

Ah ha, I didn't realize. Fixed.

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From 7f4089975fb3894cb9af5e5e7913141385d823e6 Mon Sep 17 00:00:00 2001
From: Jim Porter <jporterbugs@gmail.com>
Date: Sun, 15 Jan 2023 18:35:31 -0800
Subject: [PATCH] Add more detail about how to invoke Eshell commands

* doc/misc/eshell.texi (Variables): Move footnote explaining "REPL"
from here...
(Top): ... to its first use here.
(Commands): Move explanation about kernel functions to here.
(Invocation): Describe command form and Lisp form.  Fix documentation
about priority of commands in command form.
(Arguments): Add a cross reference to the Invocation node.
---
 doc/misc/eshell.texi | 136 +++++++++++++++++++++++++++++++------------
 1 file changed, 100 insertions(+), 36 deletions(-)

diff --git a/doc/misc/eshell.texi b/doc/misc/eshell.texi
index fc7d52eb711..ecc7bc3a011 100644
--- a/doc/misc/eshell.texi
+++ b/doc/misc/eshell.texi
@@ -64,10 +64,11 @@ Top
 
 Eshell is a shell-like command interpreter implemented in Emacs Lisp.
 It invokes no external processes except for those requested by the
-user.  It is intended to be an alternative to the IELM (@pxref{Lisp Interaction, Emacs Lisp Interaction, , emacs, The Emacs Editor})
-REPL for Emacs @emph{and} with an interface similar to command shells
-such as @command{bash}, @command{zsh}, @command{rc}, or
-@command{4dos}.
+user.  It is intended to be an alternative to the IELM (@pxref{Lisp
+Interaction, Emacs Lisp Interaction, , emacs, The Emacs Editor})
+REPL@footnote{Short for ``Read-Eval-Print Loop''.} for Emacs
+@emph{and} with an interface similar to command shells such as
+@command{bash}, @command{zsh}, @command{rc}, or @command{4dos}.
 @c This manual is updated to release 2.4 of Eshell.
 
 @insertcopying
@@ -193,6 +194,13 @@ Commands
 chapter covers command invocations in Eshell, including the command
 history and invoking commands in a script file.
 
+Unlike regular system shells, Eshell never invokes kernel functions
+directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
+available in the Emacs Lisp library.  It does this by transforming the
+input line into a callable Lisp form.@footnote{To see the Lisp form
+that will be invoked, type this as the Eshell prompt:
+@kbd{eshell-parse-command 'echo hello'}}
+
 @menu
 * Invocation::
 * Arguments::
@@ -207,23 +215,16 @@ Commands
 
 @node Invocation
 @section Invocation
-Unlike regular system shells, Eshell never invokes kernel functions
-directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
-available in the Emacs Lisp library.  It does this by transforming the
-input line into a callable Lisp form.@footnote{To see the Lisp form that will be invoked, type: @samp{eshell-parse-command "echo hello"}}
+Eshell is both a command shell and an Emacs Lisp @acronym{REPL}.  As a
+result, you can invoke commands in two different ways: in @dfn{command
+form} or in @dfn{lisp form}.
 
-The command can be either an Elisp function or an external command.
-Eshell looks first for an alias (@pxref{Aliases}) with the same name as the
-command, then a built-in (@pxref{Built-ins}) or a function with the
-same name; if there is no match, it then tries to execute it as an
-external command.
-
-The semicolon (@code{;}) can be used to separate multiple command
-invocations on a single line.  You can also separate commands with
-@code{&&} or @code{||}. When using @code{&&}, Eshell will execute the
-second command only if the first succeeds (i.e.@: has an exit
-status of 0); with @code{||}, Eshell will execute the second command
-only if the first fails.
+You can use the semicolon (@code{;}) to separate multiple command
+invocations on a single line, executing each in turn.  You can also
+separate commands with @code{&&} or @code{||}. When using @code{&&},
+Eshell will execute the second command only if the first succeeds
+(i.e.@: has an exit status of 0); with @code{||}, Eshell will execute
+the second command only if the first fails.
 
 A command invocation followed by an ampersand (@code{&}) will be run
 in the background.  Eshell has no job control, so you can not suspend
@@ -232,12 +233,80 @@ Invocation
 can be controlled the same way as any other background process in
 Emacs.
 
+@subsection Command form
+Command form looks much the same as in other shells.  A command
+consists of arguments separated by spaces; the first argument is the
+command to run, with any subsequent arguments being passed to that
+command.
+
+@example
+~ $ echo hello
+hello
+@end example
+
+@cindex order of looking for commands
+@cindex command lookup order
+The command can be either an Elisp function or an external command.
+Eshell looks for the command in the following order:
+
+@enumerate
+@item
+As a command alias (@pxref{Aliases})
+
+@item
+As a built-in command (@pxref{Built-ins})
+
+@item
+As an external program
+
+@item
+As an ordinary Lisp function
+@end enumerate
+
+@vindex eshell-prefer-lisp-functions
+If you would prefer to use ordinary Lisp functions over external
+programs, set the option @code{eshell-prefer-lisp-functions} to
+@code{t}.  This will swap the lookup order of the last two items.
+
+You can also group command forms together into a subcommand with curly
+braces (@code{@{@}}).  This lets you use the output of a subcommand as
+an argument to another command, or within control flow statements
+(@pxref{Control Flow}).
+
+@example
+~ $ echo @{echo hello; echo there@}
+hellothere
+@end example
+
+@subsection Lisp form
+Lisp form looks like ordinary Emacs Lisp code, because that's what it
+is.  As a result, you can use any syntax normally available to an
+Emacs Lisp program (@pxref{Top, , , elisp, The Emacs Lisp Reference
+Manual}).
+
+@example
+~ $ (format "hello, %s" user-login-name)
+hello, user
+@end example
+
+In addition, you can @emph{combine} command forms and Lisp forms
+together into single statements, letting you use whatever form is the
+most convenient for expressing your intentions.
+
+@example
+~ $ ls *.patch > (format-time-string "%F.log")
+@end example
+
+This command writes a list of all files matching the glob pattern
+@code{*.patch} (@pxref{Globbing}) to a file named
+@code{@var{current-date}.log} (@pxref{Redirection}).
+
 @node Arguments
 @section Arguments
-Ordinarily, command arguments are parsed by Eshell as either strings
+Ordinarily, Eshell parses arguments in command form as either strings
 or numbers, depending on what the parser thinks they look like.  To
-specify an argument of some other data type, you can use an
-@ref{Dollars Expansion, Elisp expression}:
+specify an argument of some other data type, you can use a Lisp form
+(@pxref{Invocation}):
 
 @example
 ~ $ echo (list 1 2 3)
@@ -354,10 +423,6 @@ Built-ins
 sudo is an alias, defined as "*sudo $@@*"
 @end example
 
-@vindex eshell-prefer-lisp-functions
-If you would prefer to use the built-in commands instead of the external
-commands, set @code{eshell-prefer-lisp-functions} to @code{t}.
-
 Some of the built-in commands have different behavior from their
 external counterparts, and some have no external counterpart.  Most of
 these will print a usage message when given the @code{--help} option.
@@ -923,15 +988,14 @@ Built-ins
 @node Variables
 @section Variables
 @vindex eshell-prefer-lisp-variables
-Since Eshell is a combination of an Emacs @acronym{REPL}@footnote{
-Short for ``Read-Eval-Print Loop''.
-} and a command shell, it can refer to variables from two different
-sources: ordinary Emacs Lisp variables, as well as environment
-variables.  By default, when using a variable in Eshell, it will first
-look in the list of built-in variables, then in the list of
-environment variables, and finally in the list of Lisp variables.  If
-you would prefer to use Lisp variables over environment variables, you
-can set @code{eshell-prefer-lisp-variables} to @code{t}.
+Since Eshell is a combination of an Emacs @acronym{REPL} and a command
+shell, it can refer to variables from two different sources: ordinary
+Emacs Lisp variables, as well as environment variables.  By default,
+when using a variable in Eshell, it will first look in the list of
+built-in variables, then in the list of environment variables, and
+finally in the list of Lisp variables.  If you would prefer to use
+Lisp variables over environment variables, you can set
+@code{eshell-prefer-lisp-variables} to @code{t}.
 
 You can set variables in a few different ways.  To set a Lisp
 variable, you can use the command @samp{setq @var{name} @var{value}},
-- 
2.25.1

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Eli Zaretskii]

> Date: Mon, 16 Jan 2023 12:18:13 -0800
> Cc: 60846@debbugs.gnu.org
> From: Jim Porter <jporterbugs@gmail.com>
> 
> On 1/16/2023 5:38 AM, Eli Zaretskii wrote:
> > Thanks.
> 
> Thanks for the useful feedback as always.
> 
> >> +Unlike regular system shells, Eshell never invokes kernel functions
> >> +directly, such as @code{exec(3)}.  Instead, it uses the Lisp functions
> >> +available in the Emacs Lisp library.  It does this by transforming the
> >> +input line into a callable Lisp form.@footnote{To see the Lisp form
> >> +that will be invoked, type: @samp{eshell-parse-command 'echo hello'}}
> > 
> > This should use the @kbd markup, like any command the user should
> > type.  I also suggest to say explicitly that you mean to type this at
> > the Eshell prompt, as it wasn't clear when I read it.
> 
> Fixed.
> 
> >> +The command can be either an Elisp function or an external command.
> >> +Eshell looks for the command in the following order:
> > 
> > Here I would add a few useful index entries
> > 
> >    @cindex order of looking for commands
> >    @cindex command look up, order
> 
> Done.
> 
> >> +@vindex eshell-prefer-lisp-functions
> >> +If you would prefer to use ordinary Lisp functions over external
> >> +programs, set the option @code{eshell-prefer-lisp-functions} to
> >> +@code{t}.
> > 
> > I'm guessing this swaps the order of the two last candidates, but the
> > text doesn't say that explicitly for some reason.  Just saying
> > "prefer" is not enough when you have more than 2 candidates.
> 
> Good point. I added an extra sentence explicitly stating that the last 
> two items are swapped in priority.
> 
> >> +In addition, you can @emph{combine} command forms and Lisp forms
> >> +together into single statements, letting you use whatever form is the
> >> +most convenient for expressing your intentions.
> >> +
> >> +@example
> >> +~ $ ls *.patch > (format-time-string "%F.log")
> >> +@end example
> > 
> > Either explain here the meaning of redirecting into a Lisp form, or
> > add a cross-reference to where it is explained in detail.
> 
> Done both. I've explained what the command does as well as 
> cross-referenced the globbing and redirection sections.
> 
> >> +specify an argument of some other data type, you can use a
> >> +@ref{Invocation, Lisp form}:
> > 
> > This kind of cross-references is usually a bad idea in Texinfo: it
> > looks nifty in HTML, but reads awkwardly in all other formats.  It is
> > better to use the slightly wordier alternative:
> > 
> >    specify an argument of some other data type, you can use a Lisp form
> >    (@pxref{Invocation}):
> 
> Ah ha, I didn't realize. Fixed.

Thanks, the patch LGTM now.

bug#60846: 29.0.60; [PATCH] Add more documentation about Eshell command invocation

[Jim Porter]

On 1/17/2023 5:05 AM, Eli Zaretskii wrote:
> Thanks, the patch LGTM now.

Thanks. I merged this to the Emacs 29 branch as c4f0b6ccea. Closing this 
bug now.