These are terms that appear in section 5 (Expressions) of the Python online
documentation. I'm having some trouble understanding what, precisely, these
terms mean. I'd appreciate the forum's thoughts on these questions:
1. Section 5.2.1 indicates that an identifier occurring as an atom is a name.
However, Section 2.3 indicates that identifiers are names. My question: can
an identifier be anything other than a name?
2. Section 5.3 defines primaries as the most tightly bound operations of
Python. What does this mean? In particular, if an atom is a primary, what
operation is the atom performing that leads to the label "most tightly bound"?
To put it a different way, I think of atoms as things (i.e. identifiers). The
documentation makes me think atoms actually do something, as opposed to being
things (I think I have in my mind the difference between a noun and a verb as I
write this). Perhaps the doing in this case (or binding, if you like) is
linking (binding) the identifier to the underlying object? I think it might
help if I had a better working notion of what a primary is.
3. Section 5.3.1 offers this definition of an attributeref:
attributeref ::= primary "." identifier
Now, I was at first a little concerned to see the non-terminal primary on the
right hand side of the definition, since primary is defined to include
attributeref in section 5.3 (so this struck me as circular). Am I correct in
thinking attributeref is defined this way to allow for situations in which the
primary, whether an atom, attributeref (example: an object on which a method
is called that returns another object), subscription, slicing, or call, returns
an object with property identifier?
These are, I know, long-winded questions. I appreciate in advance any thoughts
the group can offer.
The relevant documentation link is:
http://docs.python.org/2/reference/expressions.html#expressions
Thanks,
Bruce
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