Programming languages tend to evolve in response to user needs,
hardware advances, and research developments. Language evolution
artefacts may include new compilers and interpreters or new language
standards. Evolving programming languages is however challenging at
various levels. Firstly, the impact on developers can be negative. For
example, if two language versions are incompatible (e.g., Python 2 and
3) developers must choose to either co-evolve their codebase (which
may be costly) or reject the new language version (which may have
support implications). Secondly, evaluating a proposed language change
is difficult; language designers often lack the infrastructure to
assess the change. This may lead to older features remaining in future
language versions to maintain backward compatibility, increasing the
language’s complexity (e.g., FORTRAN 77 to Fortran 90). Thirdly, new
language features may interact badly with existing features, leading
to unforeseen bugs and ambiguities (e.g., the addition of Java
generics). This workshop brings together researchers and developers
interested in programming language evolution, to share new ideas and
insights, to discuss challenges and solutions, and to advance
programming language design.

Topics include (but are not limited to):

* Programming language and software co-evolution
* Empirical studies and evidence-driven evolution
* Language-version integration and interoperation
* Historical retrospectives and experience reports
* Tools and IDE support for source-code mining and refactoring/rejuvenation
* Gradual feature introductions (e.g., optional type systems)

PLE14 is colocated with ECOOP 2014 in Uppsala, Sweden.