Printing warnings and the like to the standard error stream is common
courtesy, not least because it avoids cluttering the program's output
with diagnostic messages.
Neither the 1.2 specification nor any of the proposals for 1.3 mention
using `INVISIBLE` for this purpose. Nevertheless, the operator and the
behavior described herein have seen sufficiently wide adoption in other
LOLCODE interpreters that I believe `lci` would do well to follow suit.
This patch attempts to be minimally invasive. Rather than adding a new
node type and all that that entails, the `PrintStmtNode` structure now
has a `FILE *` field containing the file to which the node should print
during interpretation. This saves a branch in `interpretPrintStmtNode()`
at the cost of making the structure negligibly larger on most systems.
Adding tests for `INVISIBLE` would require rethinking the test driver,
which presently uses the existence of output on `stderr` to detect that
an "expected error" has occurred. I'll happily try my hand at making the
necessary modifications if this patch comes to be accepted.
D.E. Akers
Justin Meza
Mark J. Reed