5 ms·

> If dereferencing would have been made implicit You're misunderstanding the comment. They aren't asking for implicit derefs. They're asking for explicit deref

> If dereferencing would have been made implicit You're misunderstanding the comment. They aren't asking for implicit derefs. They're asking for explicit derefs, using * or . instead of * or ->

psd1 3y ago
Your and GP's make no sense unless the reader knows that * is a markdown directive and infers where you typed them. Which is ironic when discussing overloading!
- dataflow 3y ago
  In confused, where in my comment does the Markdown syntax come into play? You're not seeing italics or backslashes are you?
  - psd1 3y ago
    I see now - Hacki renders italics, but the browser doesn't. Excuse my confusion, this possibility didn't occur to me.
- fanf2 3y ago
  Hacker News does not use Markdown.
  - masklinn 3y ago
    While that’s technically true, it does use a severely cut down version thereof which is worse in every way: it only supports paragraphs, code blocks, and emphasis so the ability to format is extremely limited but the emphasis can still screw you over, which requires an explicit preview (or posting) to notice. And I think escaping emphasis was only introduced somewhat recently? I do remember that for the longest time you basically had to trick HN into not breaking your comments by using a different character in stead.
  - OJFord 3y ago
    No, but it does use: * for italics, which sometimes causes a comment to go haywire because someone uses it to reference a footnote or otherwise drops it in mid-sentence, with a matching closing one, not intending italics. (Up-thread I think it probably was like that when they commented, but has since been fixed.)
    - wruza 3y ago
      Btw, you can now(?) escape * in a paragraph with \*.
      - OJFord 3y ago
        Yes, it's also automatic in some cases - originally my comment had an attempt at a joke example of it, but it was caught and didn't work. It was definitely improved relatively recently.
adrian_b 3y ago
With explicit derefs, if "*x.y" is taken to mean "(*x).y", then which is the meaning of "****x1.x2[7].x3.x4[9].x5"? > "a.b" should be enough for pointers as well, I have interpreted this to mean implicit deref, as there is no "*" (could be a formatting problem).
- dataflow 3y ago
  I think you're still misunderstanding the proposal. What are the types of your variables? This discussion makes no sense without type information. We're defining the meaning of . for pointers here. You seem to be misunderstanding the proposal as being purely a textual transformation that ignores types? The proposal is literally: "If you see . and the left operand is a pointer, pretend the . was -> instead, because otherwise the code is already invalid."
  - adrian_b 3y ago
    OK, I believe that you are right and if implicit dereferencing had been done only when this is the only interpretation that leads to a valid expression, then "->" would not have been necessary. However, I assume that this would have been a too complex solution for compilers that had to work in a few tens of kilobytes of memory, while a postfix "*", as already used a decade before C, would have been a trivial solution.
    - masklinn 3y ago
      > However, I assume that this would have been a too complex solution for compilers that had to work in a few tens of kilobytes of memory It's literally the same complexity as the type checking compilers already do to tell you that your `.` does not work because the LHS is a pointer not a struct.
      - adrian_b 3y ago
        It is not the same complexity, because syntax checking stops immediately at an error. To determine if implicit dereferencing may be applied, more analysis has to be done, because there it may be not only a pointer to a structure, but a pointer to a pointer to a structure and so on, so multiple implicit dereferencing may be needed to obtain a valid expression. However I agree that the difference in complexity is not big.

> If dereferencing would have been made implicit You're misunderstanding the comment. They aren't asking for implicit derefs. They're asking for explicit derefs, using * or . instead of * or ->

psd1 3y ago

Your and GP's make no sense unless the reader knows that * is a markdown directive and infers where you typed them. Which is ironic when discussing overloading!

dataflow 3y ago
In confused, where in my comment does the Markdown syntax come into play? You're not seeing italics or backslashes are you?
- psd1 3y ago
  I see now - Hacki renders italics, but the browser doesn't. Excuse my confusion, this possibility didn't occur to me.
fanf2 3y ago
Hacker News does not use Markdown.
- masklinn 3y ago
  While that’s technically true, it does use a severely cut down version thereof which is worse in every way: it only supports paragraphs, code blocks, and emphasis so the ability to format is extremely limited but the emphasis can still screw you over, which requires an explicit preview (or posting) to notice. And I think escaping emphasis was only introduced somewhat recently? I do remember that for the longest time you basically had to trick HN into not breaking your comments by using a different character in stead.
- OJFord 3y ago
  No, but it does use: * for italics, which sometimes causes a comment to go haywire because someone uses it to reference a footnote or otherwise drops it in mid-sentence, with a matching closing one, not intending italics. (Up-thread I think it probably was like that when they commented, but has since been fixed.)
  - wruza 3y ago
    Btw, you can now(?) escape * in a paragraph with \*.
    - OJFord 3y ago
      Yes, it's also automatic in some cases - originally my comment had an attempt at a joke example of it, but it was caught and didn't work. It was definitely improved relatively recently.

adrian_b 3y ago

With explicit derefs, if "*x.y" is taken to mean "(*x).y", then which is the meaning of "****x1.x2[7].x3.x4[9].x5"? > "a.b" should be enough for pointers as well, I have interpreted this to mean implicit deref, as there is no "*" (could be a formatting problem).

dataflow 3y ago
I think you're still misunderstanding the proposal. What are the types of your variables? This discussion makes no sense without type information. We're defining the meaning of . for pointers here. You seem to be misunderstanding the proposal as being purely a textual transformation that ignores types? The proposal is literally: "If you see . and the left operand is a pointer, pretend the . was -> instead, because otherwise the code is already invalid."
- adrian_b 3y ago
  OK, I believe that you are right and if implicit dereferencing had been done only when this is the only interpretation that leads to a valid expression, then "->" would not have been necessary. However, I assume that this would have been a too complex solution for compilers that had to work in a few tens of kilobytes of memory, while a postfix "*", as already used a decade before C, would have been a trivial solution.
  - masklinn 3y ago
    > However, I assume that this would have been a too complex solution for compilers that had to work in a few tens of kilobytes of memory It's literally the same complexity as the type checking compilers already do to tell you that your `.` does not work because the LHS is a pointer not a struct.
    - adrian_b 3y ago
      It is not the same complexity, because syntax checking stops immediately at an error. To determine if implicit dereferencing may be applied, more analysis has to be done, because there it may be not only a pointer to a structure, but a pointer to a pointer to a structure and so on, so multiple implicit dereferencing may be needed to obtain a valid expression. However I agree that the difference in complexity is not big.