OK, here is my thinking on a /help keys entry. Note: I'm using the
representation for keys used by the User's Guide -- which I assume is
the official tech pubs style -- seems we should be consistent; If we are
however, the other /help entries should be brought into compliance (they
seem to be all over the map already). May make sense to spin this off
as a separate bug, which I'd be happy to take on.
Comments welcome ---
__________________________________________________________________________________________________________________________
/help keys
==========
The jshell tool provides line editing support to allow you to navigate
within and edit snippets and commands. The current command/snippet can
be edited, or prior commands/snippets can be retrieved from history,
edited, and executed. This support is similar to readline/editline with
simple emacs-like bindings. There are also jshell tool specific key
sequences.
--- Line and history navigation ---
Return
Enters the current snippet
Left-arrow or Ctrl+B
Moves backward one character
Right-arrow or Ctrl+F
Moves forward one character
Up-arrow or Ctrl+P
Moves up one line, backward through history
Down arrow or Ctrl+N
Moves down one line, forward through history
Ctrl+A
Moves to the beginning of the line
Ctrl+E
Moves to the end of the line
Meta+B
Moves backward one word
Meta+F
Moves forward one word
Ctrl+R
Search backward through history
--- Line and history basic editing ---
Meta+Return or Ctrl+Return (depending on platform)
Insert a new line in snippet
Ctrl+_ (underscore may require shift key) or Ctrl-X then Ctrl-U
Undo edit - repeat to undo more edits
Delete
Deletes the character at or after the cursor, depending on the
operating system
Backspace
Deletes the character before the cursor
Ctrl+K
Deletes the text from the cursor to the end of the line
Meta+D
Deletes the text from the cursor to the end of the word
Ctrl+W
Deletes the text from the cursor to the previous white space
Ctrl+Y
Pastes the most recently deleted text into the line
Meta+Y
After Ctrl+Y, Meta+Y cycles through previously deleted text
Ctrl+X then Ctrl+K
Delete whole snippet
--- Shortcuts for jshell tool ---
For details, see: /help shortcuts
Tab
Complete Java identifier or jshell command
Shift+Tab then v
Convert expression to variable declaration
Shift+Tab then m
Convert statement to method declaration
Shift+Tab then i
Add imports for this identifier
--- More line and history editing ---
Ctrl+L
Clear screen and reprint snippet
Ctrl+U
Kill whole line
Ctrl+T
Transpose characters
Ctrl+X then Ctrl+B
Navigate to matching bracket, parenthesis, ...
Ctrl+X then =
Enter show current character position mode
Ctrl+X then Ctrl+O
Toggle overwrite characters vs insert characters
Meta+C
Capitalize word
Meta+U
Convert word to uppercase
Meta+L
Convert word to lowercase
Meta+0 through Meta+9 then key
Repeat the specified number of times
Where, for example, "Ctrl+A" means hold down the control key and press A.
Where "Meta" is "Alt" on many keyboards.
Line editing support is derived from JLine 3.
_______________________________________________________________________________
-Robert
On 12/8/18 11:47 AM, Jan Lahoda wrote:
On 8.12.2018 20:39, Robert Field wrote:
Thanks for updating.
Good to have /help for line editing keys, however:
(1) The supported keys should be listed without requiring that the
user knows or looks-up readline. More so, since only some readline keys
are supposed.
(2) "/edit" is a command, so with this change, typing "/help edit"
would give both the /edit and editing help -- which would be confusing.
I suggest "/help keys", there are no "k" help items.
Will do.
(3) In jshell tool online docs the tool is spelled "jshell tool"
I'd be happy to write up suggested text.
Thanks, that would be very welcome!
As to the alternative patch: I understand the motivation, it would be
nice to just use the natural "Enter" as new line. Unfortunately it's
functionality is then overloaded. I believe the alternative will be
confusing and awkward:
(1) It breaks backward compatibility in user experience, Enter has
always been accept/evaluate
(2) It would be very awkward and non-intuitive (particularly in a
long multiline snippet) to have to navigate to the end of the snippet to
accept.
Note: must be the end both vertically and horizontally.
(3) It is inconsistent: Mid snippet Enter on one line does accept.
However, on a continuation line (say after "int x =") it adds a new line
instead.
(4) It doesn't solve the problem for the most common location for
adding a new line, the end of snippet -- thus introducing more
inconsistency.
Ok. This was meant more as a backup in case there's no reasonable
shortcut we could use to add new lines.
Thanks for the comments!
Jan
Thanks,
Robert
On 12/8/18 7:21 AM, Jan Lahoda wrote:
Hi,
I've updated the patch to reflect the comments so far, the current
version is here:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.01/
Delta since the previous version is here for convenience:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.delta.00.01/
In this version, while editing a snippet, a new line can be added
using Alt-Enter (on platforms that support that), or Ctrl-Enter (on
Windows).
And alternative patch is here:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.01a/
Delta:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.delta.00.01a/
In the alternative version, Enter will only "confirm" multi-line
snippet when the cursor is at the end of the snippet, otherwise it
will add a new line (so that a special shortcut is not needed; but a
snippet cannot be "confirmed" by pressing Enter in the middle of a
multi-line snippet.)
The only difference between the .01 and .01a patches is the way they
allow to add new lines into the multi-line snippets. Other changes are
the same.
Any feedback on this is welcome.
Thanks!
Jan
On 5.12.2018 18:18, Jan Lahoda wrote:
Hi Robert,
On 4.12.2018 23:59, Robert Field wrote:
I saw no issues with JShell tool and test portions of the webrev. I
did
not review the nashorn changes.
Thanks for looking at this!
Testing it: editing multi-line snippets is vastly easier and more
intuitive.
There is one issue, with the old mechanism, as horridly clunky as it
was, you could add new lines of code (a frequently needed
functionality).
Since <return> is accept, I could find no way to add lines with this
JLine 3 version. Thoughts?
One possibility that comes to mind: pressing Enter inside the snippet
would add a new line, Enter at the very end of a (complete) snippet
would confirm that snippet. Could be fairly convenient/intuitive. What
do you think?
I looked into readline commands as an approach to addressing this,
found
nothing. However, most readline commands worked. Ctrl-u however did
not
behave as documented in readline (instead deleting to the
beginning of
the line). I notice that the there is zero in-command
documentation of
command-line editing -- not even a mention. Independent from the
review
of this port, it seems we should have in-command documentation of
command editing -- even more so now that multiline editing is useful.
This is about enhancing /help, right? I'll see what I can do.
The JShell User Manual will also need a little edit in the History
Navigation section.
Where is that?
Thanks,
Jan
-Robert
On 11/29/18 1:06 PM, Jan Lahoda wrote:
Hi,
I'd like to update the internal JLine used by JShell and jjs to
JLine
3.9.0. Two notable advantages of this version is multi-line snippet
editing and better UI on Windows (escape sequence support on
Windows).
As a consequence, this patch drops EditingHistory, as it does not
seem
to be needed anymore.
JBS:
https://bugs.openjdk.java.net/browse/JDK-8214491
The full patch is here:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.00/
To make the changes more clear, I've split it into two:
-replacement of existing JLine with the new on in
jdk.internal.le, no
changes to JLine code:
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.00.replace/
-tweaks to JLine (repackaging, eliminating references to
j.u.l.Logger,
adding hooks to wrap input streams with our stop-detecting input
stream, adding unicode escapes to unicode characters, support for
Windows without JNA), adjustments to JShell and jjs (unfortunately,
3.9.0 is not compatible with the JLine 2 branch, so the changes are
substantial):
http://cr.openjdk.java.net/~jlahoda/8214491/webrev.00.update/
Any feedback is welcome!
Thanks,
Jan
