From: "Guy N. Hurst" <gnhurst@...>
Date: 2000-11-05T21:00:11+09:00
Subject: [ruby-talk:6068] '?' questions

I have been investigating the string capabilities in depth,
and came across some issues with ascii conversions.

In other languages, chr() and ord() are functions that
convert them, as in:
chr(65) -> "A"
ord("A") -> 65

In Ruby, we use:
65.chr -> "A"
?A -> 65

Well, I was going to try to define a method String#ord, and
discovered that the '?' operator is purely a lexical thing
that looks at the character after it, so needless to say,
I had problems applying it to a string object.

Two issues follow from this.

1)
Is there some alternative to the following:

def ord
  ?(self[0].to_s)
end

obviously this doesn't work.  Am I missing some other method?


2)
In IRB, I get some funny output with '?':


irb(main):016:0> ?A
65			# ok...
irb(main):017:0> ?\\
92
irb(main):018:0> ?\1
1
irb(main):019:0> ?\6
6
irb(main):020:0> ?\7
7
irb(main):021:0> ?\8
56			# first surprise
irb(main):022:0> ?\9
57
irb(main):023:0> ?\10
8			# second surprise, but makes sense
irb(main):024:0> ?\11
9
irb(main):025:0> ?\80
SyntaxError: compile error	
(irb):25: parse error
(irb):25:in `irb_binding'
irb(main):026:0> 
irb(main):027:0> ?\70
56			# same as ?\8


I suppose it is expecting octal values...right?
Any explanation for the surprises?

Thanks,

Guy N. Hurst
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