If the command line option yus to allow the underscore character in
symbols is NOT selected, then interpret underscore as a new binary
operator meaning to do a left shift of the left side value by the
number of bit positions indicated by the right side value. As for the
arithmetic operators, both values must be literal (numeric constants
or symbols equated to a numeric constant).
several compilers:
- gcc version 4.5.3 (NetBSD nb2 20110806)
- gcc version 4.9.2 (Ubuntu 4.9.2-10ubuntu13)
- Ubuntu clang version 3.6.0-2ubuntu1 (tags/RELEASE_360/final) (based on LLVM 3.6.0)
The warnings were mostly about local variables shadowing others,
unused function parameters, and C++ style comments. Some variables were
indeed used before set.
Note that on Linux, using -std=c99 does stupid things like *remove* the
declaration of strdup() from <string.h>. Therefore I've reluctantly used
-std=gnu99.
evaluate() would not-quite-copy the original tree, which often would
get freed afterward. Including the shared parts.
Also fixed the case where evaluate() would turn a EX_NEG node into an
EX_COM node.
