Why does READ-FILE and READ-LINE return values not the same?

[SirWumpus]

READ-FILE ( caddr u1 fid -- u2 ior ) while READ-LINE ( caddr u1 fid -- u2 flag ior ) has an extra redundant flag. Surely in the case of READ-LINE ior == 0 is sufficient to indicate success as is done else where; the extra flag return value seems pointless.

[alextangent]

As specified in the standard, it is there to ensure that we can tell the difference between end-of-file and a zero length line. A single return value is not sufficient, as is explained in the annex A; https://forth-standard.org/standard/rationale#rat:file:READ-LINE. READ-FILE does not require it since there is no concept of a lines, just a requested and returned length. From: Anthony Howe ***@***.***> Sent: Thursday, August 8, 2024 3:33 PM To: ForthHub/discussion ***@***.***> Cc: Subscribed ***@***.***> Subject: [ForthHub/discussion] Why does READ-FILE and READ-LINE return values not the same? (Discussion #160) READ-FILE ( caddr u1 fid -- u2 ior ) while READ-LINE ( caddr u1 fid -- u2 flag ior ) has an extra redundant flag. Surely in the case of READ-LINE ior == 0 is sufficient to indicate success as is done else where; the extra flag return value seems pointless. — Reply to this email directly, view it on GitHub <#160> , or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAOB6OWHUPENHMCX44C6OALZQN6SZAVCNFSM6AAAAABMGUBVBOVHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZXGAZDMMRRGM> . You are receiving this because you are subscribed to this thread. <https://github.com/notifications/beacon/AAOB6OQ7QJROZF7IMTMRKJLZQN6SZA5CNFSM6AAAAABMGUBVBOWGG33NNVSW45C7OR4XAZNKIRUXGY3VONZWS33OVJRW63LNMVXHIX3JMTHAA2ZWEU.gif> Message ID: ***@***.*** ***@***.***> >

[ruv]

it is there to ensure that we can tell the difference between end-of-file and a zero length line.

BTW, an alternative way could be to store two null characters after u characters in the buffer if no line terminator was read. If a line terminator was read, these two characters are not both null characters. But checking the end-of-file condition becomes a little more difficult.