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From: Raul Jara on 19 Feb 2010 08:49 This doesn't work if you assign the strings to variables though: 'hi ' 'there' =>"hi there" hi = 'hi ' there = 'there' hi there NoMethodError: undefined method `hi' for main:Object from (irb):9 from /opt/local/bin/irb:12:in `<main>' Which is a little counter intuitive. -- Posted via http://www.ruby-forum.com/.
From: Robert Klemme on 19 Feb 2010 09:07 2010/2/19 Raul Jara <raul.c.jara(a)gmail.com>: > This doesn't work if you assign the strings to variables though: > > 'hi ' 'there' > =>"hi there" > > hi = 'hi ' > there = 'there' > hi there > NoMethodError: undefined method `hi' for main:Object > from (irb):9 > from /opt/local/bin/irb:12:in `<main>' > > > Which is a little counter intuitive. Not for me. The concatenation is done at parse time. Your "whitespace concatenation" is done at runtime. Kind regards robert -- remember.guy do |as, often| as.you_can - without end http://blog.rubybestpractices.com/
From: botp on 19 Feb 2010 09:32 On Fri, Feb 19, 2010 at 10:07 PM, Robert Klemme <shortcutter(a)googlemail.com> wrote: > 2010/2/19 Raul Jara <raul.c.jara(a)gmail.com>: >> This doesn't work if you assign the strings to variables though: >> >> 'hi ' 'there' >> =>"hi there" >> >> hi = 'hi ' >> there = 'there' >> hi there >> NoMethodError: undefined method `hi' for main:Object >> from (irb):9 >> from /opt/local/bin/irb:12:in `<main>' >> >> >> Which is a little counter intuitive. > > Not for me. The concatenation is done at parse time. Your > "whitespace concatenation" is done at runtime. as long as it's quoted string literal, try it like, >> x="robert" => "robert" >> y="raul" => "raul" >> def m >> "botp" >> end => nil >> "#{x}" \ ?> "#{y}" "#{m}" => "robertraulbotp" i think i remember a use case for this when i tried modifying a source without using an editor, ...but i still have to search for that script yet --if it's still on my newer disks... best regards -botp
From: Raul Jara on 19 Feb 2010 11:40 Robert Klemme wrote: > 2010/2/19 Raul Jara <raul.c.jara(a)gmail.com>: >> �from /opt/local/bin/irb:12:in `<main>' >> >> >> Which is a little counter intuitive. > > Not for me. The concatenation is done at parse time. Your > "whitespace concatenation" is done at runtime. > > Kind regards > > robert I guess I find it counter intuitive to have such different behaviors parse time vs. run time. If it isn't suppose to be a behavior of strings that you can stick one next to another and have them concatenate, then my brain has a hard time understanding why the parser should treat them as though they do have that behavior? -- Posted via http://www.ruby-forum.com/.
From: Robert Klemme on 19 Feb 2010 12:11
On 19.02.2010 17:40, Raul Jara wrote: > Robert Klemme wrote: >> 2010/2/19 Raul Jara<raul.c.jara(a)gmail.com>: >>> �from /opt/local/bin/irb:12:in `<main>' >>> >>> >>> Which is a little counter intuitive. >> >> Not for me. The concatenation is done at parse time. Your >> "whitespace concatenation" is done at runtime. > > I guess I find it counter intuitive to have such different behaviors > parse time vs. run time. Why? Parsing and executing are two fundamentally different things. > If it isn't suppose to be a behavior of > strings that you can stick one next to another and have them > concatenate, then my brain has a hard time understanding why the parser > should treat them as though they do have that behavior? At least because of ambiguity: this line is a valid method invocation: Robert(a)babelfish ~ $ ruby19 -ce 'foo bar' Syntax OK Robert(a)babelfish ~ $ ruby19 -e 'foo bar' -e:1:in `<main>': undefined local variable or method `bar' for main:Object (NameError) Robert(a)babelfish ~ $ There is no way the parser can disambiguate concatenation of strings referenced through variables and method invocations whereas a concatenation of string literals is easily detectable. Apart from that, I believe it is quite common in programming languages to allow concatenation of string literals although that feature might be rarely used. Kind regards robert -- remember.guy do |as, often| as.you_can - without end http://blog.rubybestpractices.com/ |