#8821: Adding a section on coercion to the tutorial (guided tour)
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Reporter: SimonKing | Owner: mvngu
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.4.4
Component: documentation | Keywords: tutorial coercion
Author: Simon King | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Comment(by leif):
There's a typo (missing space) in one headline ("Parents,types and
categories"[sic]).
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I've actually given up thinking about Sage's "coercion model", because
IMHO still different people seem to have different ideas of what it is and
how it does or should work (including different interpretations of terms).
If you want to have fun, compare this description to that in
[http://wstein.org/papers/icms/icms_2010.pdf William's and Burcin's recent
paper] (page 12)... ;-)
(Reading that, one would think ''every'' coercion in Sage is a type
'''promotion'''. "only from exact to inexact" suggests the opposite, type
'''demotion''', and does, e.g., not include
{{{QQ.has_coerce_map_from(ZZ)}}}, where I'd consider {{{ZZ}}} the [more]
"inexact" domain.)
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I'd write that Sage implements its own ''type system'', which must not be
confused with '''Python's''' (as opposed to "... type conversion and type
coercion known from, e.g., the C programming language").
The explanation that there can only be a finite number of classes in
Python is somewhat wrong; in fact, classes can be created dynamically
(regarding finite memory, there can only be finitely many instances of a
class, too).
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8821#comment:13>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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