5 ms·

Can someone explain for me?

• spott 2mo ago
  Forth I assume uses reverse polish notation: arguments before the operator. 3 4 + for example, would return 7.
  • zabzonk 2mo ago
    > would return 7 more pedantically, it would push 7 onto the stack
    • dbcurtis 2mo ago
      even more pedantically, would remove 3 and 4 from the stack before pushing 7
      • DonHopkins 2mo ago
        Even oddly more pedantically, that's the operand stack, not to be confused with the separate return stack. >R and R> move values between the two stacks. On the other hand, PostScript also has a dictionary stack, which you can use to implement a Smalltalk-like object oriented programming system. And its data types and executable code are basically polymorphic homoiconic JSON (like Lisp), not raw untyped bytes like FORTH. https://news.ycombinator.com/item?id=22456471 https://news.ycombinator.com/item?id=22456471 https://news.ycombinator.com/item?id=47812317 https://news.ycombinator.com/item?id=47812317
  • argimenes 2mo ago
    The stack is really a convenience that makes pipeline-driven programming possible in the language.
    • nagaiaida 2mo ago
      somewhat relatedly, shell pipelining is very amenable to being massaged into (non stack-based) concatenative programming
• HFguy 2mo ago
  Forth uses RPN so the "verb" is last. That is, you provide the data first (I and Forth) and the command (heart) last.
  • deleted 2mo ago
    [deleted]
  • ithkuil 2mo ago
    AKA FJN (Forward Japanese Notation)
• e12e 2mo ago
  A different way to say the same: in forth, words get pushed on the stack, and popped from the stack by words that take arguments: code stack I Forth love Forth love I love I Forth ; love presumably pops ; subject, object args ; from stack - and does something ; perhaps prints as side effect
  • forsalebypwner 2mo ago
    Is that loss?
    • joshu 2mo ago
      well played
    • fwip 2mo ago
      No.
  • DonHopkins 2mo ago
    Here is some inexplicably but meticulously formatted FORTH code that uses right justified indentation! Including reverse polish notation assembley. https://donhopkins.com/home/code/tomt-cam-forth-scr.txt https://donhopkins.com/home/code/tomt-cam-forth-scr.txt https://donhopkins.com/home/code/tomt-users-forth-scr.txt https://donhopkins.com/home/code/tomt-users-forth-scr.txt ( FMOVE -- functional intersegment move ) HEX 88 CONSTANT *MOV* ( fn = 0 ) 20 CONSTANT *AND* ( fn = 1 ) 08 CONSTANT *OR* ( fn = 2 ) 30 CONSTANT *XOR* ( fn = 3 ) CODE FMOVE ( fn s.seg s.off d.seg d.off length --) AX, SI MOV CX POP DI POP ES POP SI POP DS POP DX POP AX PUSH AL, # *XOR* MOV DX, # 3 CMP 1$ JE AL, # *OR* MOV DX, # 2 CMP 1$ JE AL, # *AND* MOV DX, # 1 CMP 1$ JE AL, # *MOV* MOV 1$: CS: HERE 5 + , AL MOV ( modify "[DI], AL MOV" ) 2$: LODS ES: [DI], AL MOV DI INC 2$ LOOP AX, CS MOV ES, AX MOV DS, AX MOV SI POP NEXT, END-CODE -->
  • e12e 2mo ago
• daureg 2mo ago
  I found https://www.explainxkcd.com/wiki/index.php/Main_Page https://www.explainxkcd.com/wiki/index.php/Main_Page quite useful for that.