Jerome BENOIT wrote:
Why would a compiler set `real' to 0.0 rather then 1.0, Pi,
.... ?
Because 0.0 is the "lowest" (smallest, starting point, etc..)
numerical value. Pi is the corner case and obviously has to be
explicitly set.
If you want to take this further, chars could even be initialized
to spaces or newlines or something similar. Pointers/references
need to be defaulted to null because they absolutely must equal
an explicit value before use. Value types don't share this
limitation.
The more convenient default set certainly depends on the
underlying mathematics,
and a compiler cannot (yet) understand the encoded mathematics.
NaN is certainly the certainly the very choice as whatever the
involved mathematics,
they will blow up sooner or later. And, from a practical point
of view, blowing up is easy to trace.
Zero is just as easy for the runtime/compiler to default to; and
bugs can be introduce anywhere in the code, not just definition.
We have good ways of catching these bugs in D with unittests
already.
