Hi
I would like to get your thoughts on the following:
Following the blog of ramon and his code in sandstoneDB which extends
dataStream
as follows:
Here is a typical example:
fileNamed: aName do: aBlock
| file | file := self fileNamed: aName.
^ file
ifNil: [ nil ]
ifNotNil: [ [ aBlock value: file ] ensure: [ file close ] ]
fileNamed: aString
"Here is the way to use DataStream and ReferenceStream:
rr := ReferenceStream fileNamed: 'test.obj'.
rr nextPut: <your object>.
rr close.
better use: fileNamed:do:
"
| strm |
strm := self on: (FileStream fileNamed: aString). "will be
binary"
strm byteStream setFileTypeToObject.
"Type and Creator not to be text, so can attach correctly to an
email msg"
^ strm
There is similar pattern in FileStream
detectFile: aBlock do: anotherBlock
| file |
file := aBlock value.
^ file
ifNil: [ nil ]
ifNotNil: [ [anotherBlock value: file] ensure: [file close]]
fileNamed: fileName
^ self concreteStream fileNamed: (self fullName: fileName)
fileNamed: fileName do: aBlock
"Avi Bryant says, ''This idiom is quite common in other languages
that make heavy use of closures
(i.e. Lisp (with-file 'foo' (f) ...) and Ruby (File.open('foo'){|
f|...})). It's time Squeak had it, too.''
Returns the result of aBlock."
^ self detectFile: [ self fileNamed: fileName ] do: aBlock
I have a question:
- would not be better to even wrap the on: into the first block of
the ensure: message?
- do we have to close a file even if its creation failed?
Stef
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