Feature #6733

New inspect framework

Added by Akira Tanaka almost 2 years ago. Updated over 1 year ago.

[ruby-core:46442]
Status:Open
Priority:Normal
Assignee:-
Category:-
Target version:Next Major

Description

After we discussed http://bugs.ruby-lang.org/issues/6291 at a developer meeting,
we re-realized new inspect framework may be useful.

Problem:
* inspect method may generate too long string but sometimes whole string is not required.
For example, first 70 characters are enough for error messages (backtrace).
* inspect can't know a encoding to be expected.
* inspect generates may short strings and discard them immediately.

If we have a new method, inspect_to(buffer), and
it (or overridden method in subclass) adds the inspected result to buffer,
we can solve above problems.
buffer has a method, <<.
It may be a string, IO or other object.

For too long string, buffer itself can throw (or raise) when buffered output is reached to a specified limit.

For encoding, buffer can record an encoding.
(p method creates a buffer object using $stdout's encoding.)

For small strings, in C level, we can create a rbbufferadd(VALUE buffer, const char *p, long len) and
it don't need to allocate a String object.

This is big change but we can preserve compatibility by following default inspect_to method:

class Object
def inspect_to(buffer)
buffer << self.inspect
end
end

If legacy class which has inspect but not inspectto,
Object#inspect
to calls inspect and use the result.

History

#1 Updated by Boris Stitnicky over 1 year ago

Thank you so much for this. Whenever I use #inspect and #to_s methods, such as when writing

puts "blah blah #{object} blah"

I cannot help but be afraid that object's #to_s method will return 20MB string, that will overrun something somewhere and take control over my computer :-)

#2 Updated by Boris Stitnicky over 1 year ago

Call me a paranoid, if you want :-)

Also available in: Atom PDF