Jython vs CPython vs PyPy vs Stackless Python vs IronPython
HotSpot vs OpenJDK vs Dalvik vs GNU Classpath (libraries only) vs Jazelle VM, etc
There is some argument as to which feedback into the language and which are "pure" implementations but I think the point still holds, many languages are pulled in many directions by either their runtime or their compiler.
Jython vs CPython vs PyPy vs Stackless Python vs IronPython
HotSpot vs OpenJDK vs Dalvik vs GNU Classpath (libraries only) vs Jazelle VM, etc
There is some argument as to which feedback into the language and which are "pure" implementations but I think the point still holds, many languages are pulled in many directions by either their runtime or their compiler.