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| Contributions |
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| 2022-03-06 21:06:16  LSchmidt  wrote:
| requestClarification - c-addr used in stack diagrams
| see: https://forth-standard.org/standard/core/Cq#contribution-226
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about representation of counted strings on stack,  `A.3.1.3.4 Counted strings` says:
> Forth 94 moved toward the consistent use of the "c-addr u" representation of strings on the stack.

While I like consistency, it appears that what was gained is a potential of confusion: c-addr appears to be used to indicate address of count byte, as it is done here.  But  elsewhere, for example with `s"`  it represents the address of the first character. It isn't obvious from the stack diagrams that those identically looking `c-addr` refer to different kind of data.

When pointing to the leading count byte of a string, the "c" in "c-addr" makes sense. But when pointing to the first character, it doesn't really. Does it imply that there's a count byte at c-addr-1? Not necessarily, I think. Then what makes such a string of characters "counted"? Shouldn't, by similar reasoning, the source address of `move`not also be "counted" - after all, there's also the count of items to move on stack, similar to the c-addr u representation of a string when c-addr points to the first character.

As I see it, there are three cases where c-addr is used to depict stack effects:
- c-addr indicating the address of a leading count byte
- c-addr indicating the address of first character in a string with a leading count byte at c-addr-1
- c-addr indicating the address of first character in a string without a leading count byte.

It is my opinion that for these three different cases not the same stack symbol ought to be used.



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| 2022-03-06 07:21:10  AntonErtl  replies:
| comment - Using a . suffix to specify a double
| see: https://forth-standard.org/standard/double/DZeroEqual#reply-802
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The . suffix is specified in [Section 8.3.1](https://forth-standard.org/standard/double#subsection.8.3.1).