References: CLHS 2.2
Edit history: 2004-06-10, Version 1 by Lars Brinkhoff
Status: For CLiki consideration
- Problem Description:
- 2.2 step 4, says "The reader macro function may return zero values or one value". Is this a strict constraint on the number of values, or does the usual "primary value" rule apply?
- Proposal (READER-MACRO-VALUES:STRICT):
- Specify that the number of values returned must be 0 or 1.
- Proposal (READER-MACRO-VALUES:LOOSE):
- Specify that any number of values may be returned; excess values are ignored.
- Test case:
- Mostly this precludes implementations from arbitraily adopting one of the two possible interpretations.
- Current practice:
- CLISP throws an error if a reader macro returns more than one value.
- Cost to Implementors:
- Cost to Users:
- None. Portable programs cannot currently rely on any particular behavior.
- Cost of Non-Adoption:
- Users would be confused about what to expect because implementations might implement either of the two behaviours.
- Tighter spec.