FORTH for Scratch 3 #MOBLuSE_FORTH

Instructions

Shift+click a green flag to start Turbo Mode, then click a green flag. It first runs a demo with graphics and sound at the end. You can then type in commands in the FORTH programming language. The FORTH programming language is good for embedded systems and is used in successful deep space missions, radio astronomy, and medical devices. This simulates a retro computer like e.g. Jupiter Ace, or ZX81 with ZX-FORTH from the early eighties. For these old computers FORTH was usually the fastest high level programming language/integrated development environment (IDE) available. http://www.forth.org/successes.html Type using these keyboard keys (due to Scratch limitations): 0-9, A-Z = types key. This FORTH is case insensitive. Arrow right = Full stop, <.>. Arrow left = Backspace, <BS>. Arrow down = Carriage return/Enter, <CR>. | is an alternative to Arrow down. Arrow up = Shift - pressed before 0-9, A-Z, <.>, <SPACE>, <CR>. \ is an alternative to Arrow up. Shift+J = -. Shift+K = +. Shift+B = *. Shift+V = /. Shift+M = >. Shift+1 = !. Shift+2 = @. Shift+I = (. Shift+O = ). Shift+P = ". Shift+Arrow right = ,. Shift+Z = :. Shift+X = ;. Shift+C = ?. Shift+A = Ask – this makes copying from a tutorial and pasting into Scratch possible – typographical quote-characters from pasted text are converted to ASCII. Shift+SPACE = Break. The keyboard layout is inspired by SPONZY – a ROM for ZX81 which makes that computer ZX Spectrum compatible (Speccy on Zeddy). If you run this on a device w/o keyboard, you may use the screen keyboard by clicking the blue keyboard in the lower right corner (same as Shift+A / Arrow up+A). You can hide the stacks by going inside and click the check-boxes for the lists in the category Data. The error codes are explained in: http://lars.nocrew.org/dpans/dpans9.htm Examples (press <CR> i.e. arrow down after each command): WORDS – Lists all commands. .KEYB – Prints the keyboard layout. : QUADRATIC ( a b c x – n ) >R SWAP ROT R@ * + R> * + ; 2 7 9 3 QUADRATIC .<CR> – Computes a*x^2 + b*x + c, where a=2, b=7, c=9, x=3. : GIFT ." chocolate" ; : GIVER ." Mum" ; : THANKS CR ." Dear " GIVER ." ," CR ." Thanks for the " GIFT ." . " ; THANKS : FACT ?DUP IF DUP 1 - FACT * ELSE 1 THEN ; 7 FACT . : STAR 42 EMIT ; : STARS 0 ?DO STAR LOOP ; : MARGIN CR 25 SPACES ; : BLIP MARGIN STAR ; : BAR MARGIN 5 STARS ; : F BAR BLIP BAR BLIP BLIP CR ; F All characters: : .charset 1 do i emit loop ; 288 .charset : .MATRIX ( r c -- ) SWAP 0 ?DO CR DUP 0 ?DO ." (" J 1 + . ." ," I 1 + . ." ) " LOOP LOOP DROP ; 5 3 .MATRIX Mutually recursive functions: : EVEN? ; : ODD? ( +n -- true | false ) DUP 0= IF EXIT THEN 1 - EVEN? ; : EVEN? ( +n -- true | false ) DUP 0= IF 1 - EXIT THEN 1 - ODD? ; This is not standard FORTH, but simpler, because this FORTH currently uses the latest definition of a word during run-time. Function pointers: : COUNTS ' ROT ROT 0 DO OVER EXECUTE LOOP NIP ; : CONVICTED-OF ( -- no-sentence ) 0 ; : ARSON ( sentence -- sentence+10 ) 10 + ; : HOMICIDE ( sentence -- sentence+20 ) 20 + ; : BOOKMAKING ( sentence -- sentence+2 ) 2 + ; : TAX-EVASION ( sentence -- sentence+5 ) 5 + ; : WILL-SERVE ( sentence -- ) . ." years " ; CONVICTED-OF BOOKMAKING 3 COUNTS TAX-EVASION WILL-SERVE Extending the compiler, example from: https://rosettacode.org/wiki/Extend_your_language : : BOTH postpone IF postpone IF ; immediate : ORELSE postpone THEN postpone ELSE postpone IF ; immediate : NEITHER postpone THEN postpone THEN ; immediate : fb ( n -- ) dup 5 mod 0= over 3 mod 0= BOTH ." FizzBuzz " ELSE ." Fizz " ORELSE ." Buzz " ELSE dup . NEITHER drop ; : fizzbuzz ( n -- ) 0 do i 1+ fb loop ; 100 fizzbuzz : STRING CREATE ALLOT DOES> + ; 5 STRING VALVE 3 VALVE C@ . I have made some new videos about this FORTH programming language and a FORTH playlist: 1. (old) https://youtu.be/VZfUFnioLko 1 min <-- Dec 26 2016 2. (new) https://youtu.be/FwEgRetggFg 1 min <-- Feb 2 2017 3. (new) https://youtu.be/tPk1nNgq6NE 1 min 4. (new) https://youtu.be/tZOYPTv77pI 1 min 5. (new) https://youtu.be/nr0c87lrC64 1 min https://www.youtube.com/playlist?list=PLD8D8534DD63B28EA Please report bugs and test-code in the comments or on GitHub!