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| Contributions |
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| 2021-03-30 16:05:59  ruv  wrote:
| requestClarification - Size of implementation dependent data types
| see: https://forth-standard.org/standard/usage#contribution-183
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May an implementation dependent data type be variable in size?

For example, may the size of _colon-sys_ from [`:`](/standard/core/Colon)  be unequal to the size of _colon-sys_ from [`:NONAME`](/standard/core/ColonNONAME)?

I think, yes, it may. But it is not obvious from the text of the standard.A practical argument is that in many implementations of `ENDOF ( C: case-sys1 of-sys -- case-sys2 )` the size of `case-sys1` is not equal to the size of `case-sys2`.



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| 2021-03-14 02:01:49  LeonWagner  replies:
| comment - Note incompatability (double v single) with some older Forth's.
| see: https://forth-standard.org/standard/core/num#reply-621
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Shouldn't the burden be on eForth to document that it is non-standard? 


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| 2021-03-14 18:43:52  AntonErtl  replies:
| comment - Note incompatability (double v single) with some older Forth's.
| see: https://forth-standard.org/standard/core/num#reply-622
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Actually # etc. use double numbers in all Forth standards.  It seems to me that it's some newer minimal systems (especially with wider cells) that don't want to implement all the prerequisites of a proper double-cell # and therefore choose to change # to work on a single cell.

It's a good idea if such systems document this deviation from standard and common practice, but given that at least one user was not aware of the difference, adding a warning here may be helpful.

It would be an even better idea if these systems used different names for their non-standard words.


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| 2021-03-26 19:57:04  JimPeterson  replies:
| referenceImplementation - Suggested reference implementation
| see: https://forth-standard.org/standard/core/TwoOVER#reply-623
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Another suggested implementation:

```: 2OVER 3 PICK 3 PICK ;```

(might be faster)


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| 2021-03-30 18:43:47  ruv  replies:
| requestClarification - Size of implementation dependent data types
| see: https://forth-standard.org/standard/usage#reply-624
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Certainly when I talk "the size of a data type", I mean the size of a data object of this data type.