A blockchain influenced by Ethereum, featuring a Forth compiler. Key components include:
- Blockchain utilizing SHA256
- Virtual Machine with stack-machine instruction sets
- Compiler for a Forth-like language
1st Block: Forth uses the so-called Reverse Polish Notation (RPN).
( simple calculation )
: main
1 2 3 4 * + + .
;
-> 4 * 3 + 2 + 1 = 15
2nd Block: New words are defined and compiled with a : to enter compilation mode and a ; to exit.
( simple function definition/call/return )
: triple
3 *
;
: main
5 triple .
;
-> 5 * 3 = 15
3rd Block: "(condition) IF (true-clause) THEN" or "(condition) IF (true-clause) ELSE (false-clause) THEN".
( simple conditional statement )
: main
2 1 > if 100 then .
;
-> 100
4th Block: Nested control structure.
( nested conditional statements )
: main
1 2 + 2 > if
7 2 4 3 - < if
0 else
7 then
7 then
* * .
;
-> 7 * 7 * 7
5th Block: Recursive Call.
( recursive call )
: factorial
dup 1 > if
dup 1 - factorial * then
;
: main
5 factorial .
;
-> 5 * 4 * 3 * 2 * 1
6th Block: Tail-call of recursive function.
( tail-call )
: tail_factorial
dup 1 > if
swap over * swap 1 - tail_factorial then
;
: main
1 5 tail_factorial drop .
;
-> 5 * 4 * 3 * 2 * 1
7th Block: Nested function call.
( nested function call )
: sq
dup *
;
: fourth_power
sq sq
;
: main
3 fourth_power .
;
-> 3 * 3 * 3 * 3
8th Block: You can use a function from previous blocks.
( calling functions in old blocks )
: main
3 factorial fourth_power .
;
-> ( 3 * 2 * 1 ) * ( 3 * 2 * 1 ) * ( 3 * 2 * 1 ) * ( 3 * 2 * 1 )
9th Block: Volatile variables, which are not recorded in the binary data in the block.
( volatile variables )
: main
variable XXX 10
variable YYY 20
XXX YYY * .
;
-> 10 * 20
10th Block: The word ! stores a value at the memory location, and the word @ fetches from the memory. These operations are recorded in the block.
( storage variables )
: main
3 XXX !
XXX @ .
;
-> 3
The hash function is from zedwood.com. I also referred to the sites below:
- http://www.zedwood.com/article/cpp-sha256-function
- https://ethereum.github.io/yellowpaper/paper.pdf
- https://github.com/ethereum/wiki/wiki/Ethereum-Development-Tutorial
- http://www.complang.tuwien.ac.at/forth/gforth/Docs-html/
- http://www.forth200x.org/documents/forth16-1.pdf
- https://github.com/teaandcode/TestChain
- https://gist.github.com/kumaashi/6d4c83b635fdd996fd67bb8f887bec43