2011/10/30 Sven Van Caekenberghe sven@beta9.be:
Nicolas,
On 30 Oct 2011, at 17:07, Nicolas Cellier wrote:
There is a huge mess in #readFrom: implementation. Some classes will signal trailing characters as a bug, some other won't and will simply leave the stream positioned after the valid part. I propose to change this behaviour uniformly:
- readFrom: aStream will never fail on trailing chars (hey, it's a
stream, it's up to sender to interpret the tail)
- readFromString: aString will always forbid trailing char (it's not a
stream, so this garbage is most probably an error and cannot be ignored silently)
What do you think ?
Will that not break the idiom (lazy implementation)
readFromString: string ^ self readFrom: string readStream
?
That's it, I would change for something like
readFromString: aString | aStream newInstance | aStream := aString readString. newInstance := self readFrom: aStream. aStream atEnd ifFalse: [FormatError raise]. ^newInstance
BTW, what I miss in Smalltalk is a way to read from some position to another without all the terrible copying, either from a stream or from a string.
There is ReadStream class>>on:from:to: but I recommend testing and testing again, because Stream implementation is ... not crystal clear.
Consider parsing something like this '2011-10-30T17:17:47+01:00', the fields are fixed and pretty simple, but I can't think of an efficient way to do it, can you ?
Don't know... Some pattern matching, maybe with a simple regexp. PEG might be simple too. Qualifying as "efficient" however raise the bar a bit high ;)
Nicolas
Sven