> unless you assume its existence and availability via streams in the first place
That's given by a conforming, hosted implementation of ISO C (the usual kind). You seem to have been writing about freestanding implementations. We are then severely restricted; there might not be a malloc.
C99 4. Conformance ΒΆ6: "The two forms of conforming implementation are hosted and freestanding. A conforming hosted implementation shall accept any strictly conforming program. A conforming freestanding implementation shall accept any strictly conforming program that does not use complex types and in which the use of the features specified in the library clause (clause 7) is confined to the contents of the standard headers <float.h>, <iso646.h>, <limits.h>, <stdarg.h>, <stdbool.h>, <stddef.h>, and <stdint.h>."
If we are talking hosted, then <stdio.h> streams have to be present as a required feature.
> you can specify the semantics of an unbounded storage system via built-in mechanisms and data structures of these languages.
Which language states that programs must be successfully processed by an implementation, regardless of the resources that they require? The next cons call in your Lisp image could fail. That's no different from a stream-related resource problem.
The thought experiment behind "can this programming language express Turing computation" requires us to imagine, for all languages, that the resource constraints don't exist. The question is whether there are some limitations in the language semantics which cannot be thus hand-waved away. Freestanding C (without streams) has those limitations in the abstract semantics; hosted C doesn't. The abstract semantics of streams is available, and if we imagine that to be free of platform-related resource limitation, then we are in the same league as the other languages that we have imagined to be free of platform-related resource limitations.
That's given by a conforming, hosted implementation of ISO C (the usual kind). You seem to have been writing about freestanding implementations. We are then severely restricted; there might not be a malloc.
C99 4. Conformance ΒΆ6: "The two forms of conforming implementation are hosted and freestanding. A conforming hosted implementation shall accept any strictly conforming program. A conforming freestanding implementation shall accept any strictly conforming program that does not use complex types and in which the use of the features specified in the library clause (clause 7) is confined to the contents of the standard headers <float.h>, <iso646.h>, <limits.h>, <stdarg.h>, <stdbool.h>, <stddef.h>, and <stdint.h>."
If we are talking hosted, then <stdio.h> streams have to be present as a required feature.
> you can specify the semantics of an unbounded storage system via built-in mechanisms and data structures of these languages.
Which language states that programs must be successfully processed by an implementation, regardless of the resources that they require? The next cons call in your Lisp image could fail. That's no different from a stream-related resource problem.
The thought experiment behind "can this programming language express Turing computation" requires us to imagine, for all languages, that the resource constraints don't exist. The question is whether there are some limitations in the language semantics which cannot be thus hand-waved away. Freestanding C (without streams) has those limitations in the abstract semantics; hosted C doesn't. The abstract semantics of streams is available, and if we imagine that to be free of platform-related resource limitation, then we are in the same league as the other languages that we have imagined to be free of platform-related resource limitations.