alias refactorings

docs/source/todo.rst

@@ -13,7 +13,7 @@ Future Things and Ideas
 - make builtin functions capable of returning multiple values, then make divmod() return the 2 results rather than accepting 2 extra variables as arguments
 - then also introduce lmh(longvalue) -or whatever sensible name- builtin function that returns the low, mid, hi (bank) bytes of a long.
 - and rewrite the divmod (and others?) function to just return the 2 results instead of taking target variables as arguments.
-- allow alias to blocks?
+- allow alias to blocks?  There's some code look for "experimental code to be able to alias blocks"
 - add a -profile option (for now X16 only) that instruments the start (and returns?) -of every prog8 subroutine with code that dumps to the X16 emulator debug console: name of sub, stack pointer (for call depth!), emudbg cycle count. Save/restore all used registers!  Start of program must set cycle count to zero.
 - add @private to variables and subroutines declared in a scope to make them invisible from outside that scope?
 - when implementing unsigned longs: remove the (multiple) "TODO "hack" to allow unsigned long constants to be used as values for signed longs, without needing a cast"
@@ -31,7 +31,6 @@ Future Things and Ideas
 - should we have a SourceStorageKind.POINTER?   (there is one for TargetStorageKind...)
 - make memory mapped variables support more constant expressions such as:  &uword  MyHigh = &mylong1+2 (see github issue #192)
 - allow memory() to occur in array initializer (maybe needed for 2 dimensional arrays?) i.e. make it a constant (see github issue #192)
-- handle alias in a general way in LiteralsToAutoVarsAndRecombineIdentifiers (or a whole separate ast processing step to avoid any replacement conflicts) instead of replacing it scattered over multiple functions
 - allow the value of a memory mapped variable to be address-of another variable, not just a constant number
 - implement for loops with long loopvar over long range expression
 - Make all constants long by default? or not? (remove type name altogether), reduce to target type implictly if the actual value fits.  Experiment is in branch 'long-consts'