From: 7stud 7stud <dolgun@...>
Date: 2007-03-11T21:40:31+09:00
Subject: string to int: ruby documentation?

Hi,

In trying to convert a string to an integer, I found this passage in the
ruby documentation:
http://dev.rubycentral.com/ref/

-------------
str.to_i -> anInteger

Returns the result of interpreting leading characters in str as a
decimal integer. Extraneous characters past the end of a valid number
are ignored. If there is not a valid number at the start of str, 0 is
returned. The method never raises an exception.
-------------

That description seems complete.  It talks about edge cases, and what
happens, and that the method doesn't throw an exception.  Then I found
this passage:

-----------
Integer( arg ) -> anInteger

Converts arg to a Fixnum or Bignum. Numeric types are converted directly
(with floating point numbers being truncated). If arg is a String,
leading radix indicators (0, 0b, and 0x) are honored. This behavior is
different from that of String#to_i.
------------

In that description, there is no mention of exceptions that can be
thrown, but when I try the Integer() method, this is the output:

irb(main):002:0> Integer("10")
=> 10
irb(main):003:0> Integer("10abc")
ArgumentError: invalid value for Integer: "10abc"
        from (irb):3:in `Integer'
        from (irb):3
irb(main):004:0> Integer("hello")
ArgumentError: invalid value for Integer: "hello"
        from (irb):4:in `Integer'
        from (irb):4
irb(main):005:0>

So, it seems pretty clear that the Integer() method can throw an
ArgumentError exception, and I'm wondering why the docs don't mention
what exceptions Integer() throws?  Is that typical of the docs?  If it
doesn't say "no exceptions are thrown", should I assume it can throw
some as yet unidentified exception?

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