Last patch didn't apply anymore, updated one attached.

Lachlan, can this be made a configurable option, preferrably in the editor menu toolbar? Sometimes the hovering + popups are a bit in the way, so it would be nice if they can be shut off.
Or maybe the time-to-popup would just need to be twice or three times as long (or configurable in the editor preferences).

(file #38010)

Thanks for testing this again, Philip.

It seems that the Windows version still has a title bar.  I tried to get rid of that.  (There isn't one on my Linux system.)  Do you need to click on the X to clear it, or does it go when you move the mouse?

You're right that it gets messy for large matrices, but I think Matlab does too.  My goal is to have some useful summary statistics for large matrices: perhaps the output of matrix_type, perhaps the maximum and minimum values (and their locations?), perhaps whether it is non-negative.  Many of my matrices are sparse but stored as full, so I was thinking of using the sparse representation if the matrix is "sparse enough".

Any suggestions of how you would like the output are welcome :)

Oops. Thanks!  Trying again.

(file #37881)

This patch, in three changesets, causes the value of a variable to be displayed when the cursor hovers over it, as Matlab does.  (Philip, you mentioned that this would be useful, so I'm adding you to the Cc list.)

The first two patches (display_mutex and display_hover) have been separated out because they provide "infrastructure" that is likely to be useful for other tasks.

The first provides a thread-safe (i.e., locked) mechanism to allow the GUI to call quick functions from the core.  It uses a very coarse-grained mutex lock, which the core holds whenever it is not doing a readline.  That minimizes the locking overhead, while still allowing the GUI access while the user is debugging or writing code.

The second provides "hover" events when the mouse stays still over the edit area for more than 0.5s.  In future, this will allow us to show the matching if/while etc. when hovering over an endif/endwhile/end, or the usage info for a function.

The final patch, display_show_vars, responds to the hover signal by displaying the variable name, size, type and value. Some, such as large diagonal matrices, are displayed in a more compact form than print() gives, but most just use print().

One caveat is that, like Matlab, this just looks at the string under the cursor and evaluates it in the current context, even if the cursor is over a function in a different context.  In the future, I hope to have the full parse tree accessible to the GUI, which would allow us to determine which function the cursor is in, and look for the appropriate stack frame.