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Status: passed, June 87


References: COMPILE (p438), COMPILE-FILE (p439)


Edit history: Version 1 by Pitman 02/27/87

Version 2 at committee meeting 15-Mar-87

Version 3 Masinter 15-Mar-87

Version 4 by Fahlman, incorporate Dribble

Version 5 by Masinter, 29-May-87, revert to Version 3

Version 6 by Masinter, 5-Jun-87, minor formatting

Problem Description:

The description of the COMPILE and COMPILE-FILE functions does not

explicitly permit them to print warnings. If this is to be allowed, it

should be an explicitly expressed part of the contract.


COMPILE and COMPILE-FILE are permitted to output warnings; warnings

should go to the stream that is the value of *ERROR-OUTPUT*.


Compiler warning output is a widely accepted extension to the

compilation. Warnings that come via the WARN function will go to the

stream that is the value of *ERROR-OUTPUT*.

Current Practice:

Some implementations send compiler warning output to *ERROR-OUTPUT*.

Other implementations send it to *STANDARD-OUTPUT*.

Adoption Cost:

In most cases, the change to the compiler to redirect output is expected to be very slight.


Currently, it is difficult to redirect the output of COMPILE and

COMPILE-FILE because it isn't clear where it's directed.

Conversion Cost:

Most user programs that care are probably already tolerant of both

situations or naively expect that output will go to *ERROR-OUTPUT*. As

such, most users will probably perceive this as a clarification.


Most users will probably perceive this change as a simplification

because it will allow the kind of warning that comes from WARN and the

kind of warning that comes from compilation to be conceptually grouped.


This was a problem in adapting MACSYMA to Common Lisp because Macsyma

provides alternate user interfaces to the compiler which it needs to be

able to control.

The committee considered extending the proposal to describe the

interaction with DRIBBLE on the warning output, but found that DRIBBLE

was so underspecified as to make the task impossible. DRIBBLE should be

considered in a separate proposal.

The cleanup committee supports this change as stated.

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