Difference between revisions of "Internal and Expanded"
| Line 4: | Line 4: | ||
To make the discussion consistent, let's suppose we have the following set of classes: | To make the discussion consistent, let's suppose we have the following set of classes: | ||
| − | < | + | <e> |
class A | class A | ||
feature | feature | ||
| Line 21: | Line 21: | ||
sc: STRING | sc: STRING | ||
end | end | ||
| − | </ | + | </e> |
==Nothing special== | ==Nothing special== | ||
| Line 30: | Line 30: | ||
==Extra fields== | ==Extra fields== | ||
| − | The attributes of the expanded are also visible as extra fields of the object. In other words | + | The attributes of the expanded are also visible as extra fields of the object. In other words, we would see for class A either one of the following: |
| + | #All components: | ||
| + | #* b | ||
| + | #* b.c | ||
| + | #* b.c.sc | ||
| + | #* b.sb | ||
| + | #* sa | ||
| + | #All first level components and then only necessary components: | ||
| + | #* b | ||
| + | #* b.c.sc | ||
| + | #* b.sb | ||
| + | #* sa | ||
| + | #Necessary components: | ||
| + | #* b.c.sc | ||
| + | #* b.sb | ||
| + | #* sa | ||
| + | |||
| + | Clearly the thrid option is what is enough, however it would break existing code relying on the presence of ''b''. So we will offer the second variant with a flag to say if the field was an extra field or not. | ||
Revision as of 09:39, 23 March 2010
We are discussing here how to export the description of expanded fields in a normal object to enable a fast and efficient introspection of objects at runtime. We will describe the various possibilities the last one being the implementation we have chosen in EiffelStudio.
To make the discussion consistent, let's suppose we have the following set of classes:
class A feature b: B sa: STRING end expanded class B feature c: C sb: STRING end expanded class C feature sc: STRING end
Nothing special
As of version 6.5 and before of EiffelStudio, one can use `field' and `set_field' to get and set the expanded attributes
pros: simple cons: very inefficient
Extra fields
The attributes of the expanded are also visible as extra fields of the object. In other words, we would see for class A either one of the following:
- All components:
- b
- b.c
- b.c.sc
- b.sb
- sa
- All first level components and then only necessary components:
- b
- b.c.sc
- b.sb
- sa
- Necessary components:
- b.c.sc
- b.sb
- sa
Clearly the thrid option is what is enough, however it would break existing code relying on the presence of b. So we will offer the second variant with a flag to say if the field was an extra field or not.
