Ruby language upgrade improves garbage collection, pattern matching

Ruby 2.7 preview includes enhancements to the REPL, experimental just-in-time compiler

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(Image: Ruby)

24 June 2019

Ruby 2.7, the latest upgrade of the Ruby programming language, is now in a preview release. Ruby 2.7 brings improvements in garbage collection, pattern matching, and REPL (read-eval-print-loop).

The general release is planned for December 2019. New in the Ruby
preview release is compaction garbage collection, which is used to
defragment a fragmented memory space. The GC.compact method
compacts the objects in the heap so that fewer pages are used. Members
of the Ruby development team explained that some multi-threaded Ruby
programs may cause memory fragmentation, which leads to high memory
utilization and speed degradation.

Other improvements in Ruby 2.7.0 include:

An experimental pattern matching capability, which can traverse a
given object and assign a value if it matches a pattern. Pattern
matching is widely used in functional programming languages.
Multi-line editing is now supported in irb, the interactive Ruby shell. Integration with rdoc, the Ruby documentation system, also is provided. With irb, developers can display the reference for a class, method, or module. Also, source lines shown at binding.irb and inspect results for core-class objects now are colorized.
For the still-experimental just-in-time (JIT) compiler, first introduced in Ruby 2.6,
JIT-ed code is recompiled to less-optimized code when an optimization
has been invalidated. Further, method inlining is performed when a
method is considered pure. However, many methods are not yet considered
pure.
An Enumerable#tally counts the occurrence of each element.
A method reference operator, .:, is included on an experimental basis.
Also introduced as an experimental feature is a numbered parameter as the default block parameter.