Rel version 3.011 now available!

This release of Rel, an implementation of Date & Darwen’s Tutorial D database language, improves the user interface and fixes some bugs.

The following enhancements have been made:

Rel UI: Opening a relvar in Edit mode now positions the cursor in the blank row at the bottom, ready to enter a new tuple. Cursor keys may be used to navigate, and Ctrl/Cmd-Cursor keys may be used to jump to top/bottom or right/left.

Rel UI: Font scaling has been improved when using alternative output display on HiDPI Windows displays.

Rel UI: The bundled Java runtime is now version 8u161.

Rel DBMS: Using SAME_HEADING_AS(…) in a relation literal heading was previously not permitted. E.g., REL SAME_HEADING_AS(S) {} was a syntax error. It is now permitted.

Rel DBMS and Rel Client now check for and correctly handle ‘null’ source code.

The following bugs have been fixed:

Rel UI: Cut/copy/paste/selectAll drop-down menus and keyboard shortcuts now work consistently and are generally available wherever they should appear.

Rel DBMS: ABS(n) always returned a RATIONAL value, even if n was INTEGER. Fixed.

Rel UI:

Given: Ubuntu 16.xx, 17.xx and other GTK3 environments.

Result: Multiple GUI failures similar to those when using the
Eclipse IDE under GTK3.

Fixed. Startup forces GTK2. Some issues remain, but at least it’s

Rel UI:

Given: In the relvar Edit mode, press “Go to INSERT row” button on
relvar with high enough cardinality to require scrolling.

Result: It was was supposed to do what Ctrl-End should also do:
position the display on the blank row and put the cursor in it. It

Fixed. Ctrl-Cursor preferred over Ctrl-End.

– Rev:

Given: Create an Expression and set its text to “WRITELN ‘&blah'”.

Result: The & won’t show. If you change the text to “WRITELN
‘&&blah'”, it shows &, but is treated as “WRITELN ‘&&blah'”.



Given: viewtopic.php?f=2&t=1527&p=2863#p2863

Result: Fatal error instead of semantic error.

Fix: Now throws semantic error, plus gives a helpful hint for fixing
a typical error.


Given: S GROUP {blah} AS rva

Result: Java NullPointerException due to undefined attribute ‘blah’.


For more information, or to download Rel, go to

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