SRFI 70: Numbers

by Aubrey Jaffer

status: final (2005-09-11)

keywords: Data Structure, Numbers

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Abstract

This SRFI proposes text to replace section 6.2 "Numbers" of R5RS in order to extend its capabilities, correct errors in its specification, make it more explicit about limitations of precision and magnitude, and improve portability between implementations. More specifically, this new text:

• incorporates an inexact real positive infinity and an inexact real negative infinity,
• extends number syntax to incorporate inexact real infinities,
• adapts Common-Lisp semantics for `expt' and extends them to include inexact real infinities,
• corrects the description of `sqrt',
• sharpens the distinction between exact and inexact numbers,
• removes a contradiction related to exactness,
• extends `gcd' and `lcm' to exact rational numbers,
• extends `quotient', `modulo', and `remainder' to finite real numbers,
• clarifies the behavior of `inexact->exact' applied to an exact argument,
• clarifies the behavior of `exact->inexact' applied to an inexact argument,
• adds convenience procedures `exact-round', `exact-ceiling', `exact-floor', and `exact-truncate',
• and adds examples.