/** Each command now points to a typechecked Expr. */
private void resolveCommands(Expr globalFacts) throws Err {
ConstList<Sig> exactSigs = ConstList.make(world.exactSigs);
for(int i=0; i<commands.size(); i++) {
Command cmd = commands.get(i);
cmd = resolveCommand(cmd, exactSigs, globalFacts);
commands.set(i, cmd);
}
}