Implemented some new words in forth.s:
* 'DODOES
Gives the address of the assembly for DODOES. Used by DOES> when compiling
machine code to jump to it and activate the following high-level forth
code. This is how non-primitive actions for a word can be set.
* LATEST!
Sets the LATEST pointer. For when the user wants to write their own way of
extending the dictionary (word lists, vocabularies, etc).
* R@
Copies the top of the return stack to the data stack. Useful for when loops
start getting non-trivial and you start wondering of all those ROTs aren't
efficient enough. Maybe someday we'll implement a register-allocating
compiler. Probably not. Too complicated for bootstrapping.
* Not really words but used: DODOES and DOVAR.
DOVAR is the default behavior of CREATEd words - it just pushes a pointer to
whatever was allotted right after the word was created. DODOES is jumped to in
order to invoke high-level forth behaviors for words.
* Changed behavior of CREATE to better match the way it usually works.
Added some words to inital_library.fs (we should fix that name sometime):
* Added a variable BASE to control what base numbers are printed in.
* Turns out I misunderstood what WORD did and mis-diagnosed an early problem in
' - so it turns out that nothing was being allotted in the dictionary, just
stuff in "string space", which if I understand properly just sort of fills up
infinitely as long as WORD is being invoked. Some other forths try to solve
this by introducing an input buffer for the current line, at the cost of some
complexity (as words like [CHAR] and S" have to take that into
account). Anyway, the HERE and DP! are gone from ' now.
* Added BOUNDS for common setup for sequence-iterating loops.
* Added region-comment "(" (note that it doesn't nest), used most often for
stack comments.
* Added hex dump printer DUMP and support words, number of bytes printed per
line is controlled by LINE-SIZE. It looks pretty nice, much of the design is
based off of gforth's.
* Added DOES> and supporting words, and used it to make VARIABLE, CONSTANT, and
DEFER.
* Added TUCK, MIN, SPACES, :NONAME, FILL, and <>.
Add LSHIFT and RSHIFT to the wishlist, as ghetto shifting with division seems to
behave a bit strangely when given negative values.
Also, we're now advanced enough to support the tictactoe I wrote awhile back for
gforth! http://paste.lisp.org/display/349394
Some of the comments seemed a bit off. Additionally, there was a bug in AGAIN
in which it didn't actually compile a jump. Also, WHILE's compile-time stack
effect is now consistent with gforth, which means we can have multi-exit while
loops. Also, added UNTIL. Also, added [CHAR] so we don't have to keep looking up
ascii values for characters. Also, whichever bug it was that caused problems
with splitting definitions up across multiple lines is now gone, so long live
the newlines!
Jeremiah Orians
Jan Nieuwenhuizen
Caleb Ristvedt