Sufficiently Small

To compile the code comprising an OWL BASIC procedure, function or main program into CIL, we must linearise the Control Flow Graph (CFG) representing the program statements. The CFG undergoes many transformations during compilation, for example to eliminate unreachable code or convert GOSUB routines into named procedures. Generation of CIL using Reflection.Emit requires [...]

After a long haul, and diversions into other more important projects — including starting a family — OWL BASIC today produced its first executable. Its not much. In fact its hardly anything. Just 2048 bytes of Windows PE executable containing the global variable declarations from Acornsoft’s 1982 Sphinx Adventure. Each file of BASIC source [...]

After 15 years programming in C++, I was surprised to discover today that throw in C++ is an expression rather than a statement. As a result, throw may be used as part of larger expressions.

int x = 5;
int y = x > 4 ? x : throw std::out_of_range;

The only use I’ve found for this — [...]

Eclipse doesn’t come with an installer for Windows. As a result of this, installing Eclipse into Program Files is very awkward without getting into a tussle with User Account Control, and virtualisation of the Program Files directory.
After far too much effort I have finally found a sequence that Works For Me™ on Windows Vista [...]

Europython 2009 was my first Python conference, this being the first year that I’ve been able to use Python professionally for application development. We’d made a decision that if we were to be using Python commercially, we should be active within the Python community, so two of our team travelled from Norway to Birmingham, UK. [...]

Jython and IronPython run on platforms where strings are unicode capable by default. Both implementations have chosen to make str essentially an alias for unicode in Python source code. The bytes type, introduced in PEP358 as part of transition to fully unicode Python 3.0, is unambiguously a sequence of single byte values. We can see [...]

Earlier today I posted the second article in what is turning out to be a short series in the investigation into why the performance of IronPython is around 100× slower than CPython, when running the front-end of my OWL BASIC compiler.
The most informative comment was from Curt Hagenlocher who works on IronPython in the Visual [...]

IronPython 2.0 can be hundreds of times slower than CPython on some microbenchmarks. Jython 2.5 can scale better than CPython on those same benchmarks.

IronPython can be slow – 10x to 100x slower than CPython on real-world code and it has been observed to be up to 6000x slower.

For a useful re-implementation of BBC BASIC, especially in compiled form, a run-time system is needed to provide services to the running program which cannot be directly provided by the operating system. In the case of our OWL BASIC implementation, we are targeting .NET so we already have a very sophisticated run-time in the [...]