Ruby Can I write multi-line string with no concatenation

Question

Is there a way to make this look a little better   conn exec  select attr1  attr2  attr3  attr4  attr5  attr6  attr7                from table1  table2  table3  etc  etc  etc  etc  etc                 where etc etc etc etc etc etc etc etc etc etc etc etc etc    Like  is there a way to imply concatenation

User · Answer

If you do mind extra spaces and newlines, you can use

conn.exec %w{select attr1, attr2, attr3, attr4, attr5, attr6, attr7
  from table1, table2, table3, etc, etc, etc, etc, etc,
  where etc etc etc etc etc etc etc etc etc etc etc etc etc} * ' '

(use %W for interpolated strings)

User · Answer

To avoid closing the parentheses for each line you can simply use double quotes with a backslash to escape the newline    select attr1  attr2  attr3  attr4  attr5  attr6  attr7   from table1  table2  table3  etc  etc  etc  etc  etc    where etc etc etc etc etc etc etc etc etc etc etc etc etc

User · Answer

conn exec    lt  lt eos   select attr1  attr2  attr3  attr4  attr5  attr6  attr7   from table1  table2  table3  etc  etc  etc  etc  etc    where etc etc etc etc etc etc etc etc etc etc etc etc etc eos

User · Answer

You can also use double quotes  x       this is  a multiline string      2 3 3  012  gt  x    gt    nthis is na multiline nstring n    If needed to remove line breaks   n  use backslash     at the end of each line

User · Answer

Other options    multi line string multiline string    lt  lt EOM This is a very long string that contains interpolation like   4   5   n n EOM  puts multiline string   another option for multiline string message    lt  lt -EOF asdfasdfsador   2 2  this month  asdfadsfasdfadsfad  EOF  puts message

User · Answer

conn exec      select attr1  attr2  attr3           from table1  table2  table3           where        join        This suggestion has the advantage over here-documents and long strings that auto-indenters can indent each part of the string appropriately   But it comes at an efficiency cost

User · Answer

There are multiple syntaxes for multi-line strings as you ve already read  My favorite is Perl-style   conn exec  q select attr1  attr2  attr3  attr4  attr5  attr6  attr7       from table1  table2  table3  etc  etc  etc  etc  etc        where etc etc etc etc etc etc etc etc etc etc etc etc etc    The multi-line string starts with  q  followed by a      or    and then terminated by the corresponding reversed character   q does not allow interpolation   Q does so you can write things like this   conn exec  Q select attr1  attr2  attr3  attr4  attr5  attr6  attr7       from   table names         where etc etc etc etc etc etc etc etc etc etc etc etc etc    I actually have no idea how these kinds of multi-line strings are called so let s just call them Perl multilines   Note however that whether you use Perl multilines or heredocs as Mark and Peter have suggested  you ll end up with potentially unnecessary whitespaces  Both in my examples and their examples  the  from  and  where  lines contain leading whitespaces because of their indentation in the code  If this whitespace is not desired then you must use concatenated strings as you are doing now

User · Answer

Recently with the new features in Ruby 2 3 the new squiggly HEREDOC will let you write our multiline strings in a nice manner with a minimal change so using this combined with the  squish  if you are using rails  will let you write multiline in a nice way  in case of just using ruby  you can do a  lt  lt  SQL split join      which is almost the same   1  pry main  gt   lt  lt  SQL squish  1  pry main     select attr1  attr2  attr3  attr4  attr5  attr6  attr7  1  pry main     from table1  table2  table3  etc  etc  etc  etc  etc   1  pry main     where etc etc etc etc etc etc etc etc etc etc etc etc etc  1  pry main   SQL   gt   select attr1  attr2  attr3  attr4  attr5  attr6  attr7 from table1  table2  table3  etc  etc  etc  etc  etc  where etc etc etc etc etc etc etc etc etc etc etc etc etc    ref  https   infinum co the-capsized-eight multiline-strings-ruby-2-3-0-the-squiggly-heredoc

User · Answer

Yes  if you don t mind the extra newlines being inserted    conn exec  select attr1  attr2  attr3  attr4  attr5  attr6  attr7             from table1  table2  table3  etc  etc  etc  etc  etc              where etc etc etc etc etc etc etc etc etc etc etc etc etc    Alternatively you can use a heredoc   conn exec  lt  lt -eos    select attr1  attr2  attr3  attr4  attr5  attr6  attr7    from table1  table2  table3  etc  etc  etc  etc  etc     where etc etc etc etc etc etc etc etc etc etc etc etc etc eos

User · Answer

In ruby 2 0 you can now just use   For example      SQL            SELECT user  name       FROM users       WHERE users id     var        LIMIT   var2

User · Answer

Like you  I was also looking for a solution which does not include newlines   While they may be safe in SQL  they re not safe in my case and I have a large block of text to deal with   This is arguably just as ugly  but you can backslash-escape newlines in a heredoc to omit them from the resulting string   conn exec  lt  lt  END OF INPUT     select attr1  attr2  attr3  attr4  attr5  attr6  attr7       from table1  table2  table3  etc  etc  etc  etc  etc        where etc etc etc etc etc etc etc etc etc etc etc etc etc   END OF INPUT   Note that you cannot due this without interpolation  I E   lt  lt   END OF INPUT   so be careful    expressions  will be evaluated here  whereas they will not in your original code  A  Wilson s answer may be better for that reason

User · Answer

Sometimes is worth to remove new line characters  n like   conn exec  lt  lt -eos squish  select attr1  attr2  attr3  attr4  attr5  attr6  attr7  from table1  table2  table3  etc  etc  etc  etc  etc   where etc etc etc etc etc etc etc etc etc etc etc etc etc eos

User · Answer

Elegant Answer Today    lt  lt  TEXT Hi   user name     Thanks for raising the flag  we re always happy to help you  Your issue will be resolved within 2 hours  Please be patient   Thanks again  Team   user organization name  TEXT   Theres a difference in  lt  lt -TEXT and  lt  lt  TEXT  former retains the spacing inside block and latter doesn t   There are other options as well  Like concatenation etc  but this one makes more sense in general   If I am wrong here  let me know how

User · Answer

The Ruby-way  TM  since Ruby 2 3  Use the squiggly HEREDOC  lt  lt   to define a multi-line string with newlines and proper indentation  conn exec  lt  lt  EOS             select attr1  attr2  attr3  attr4  attr5  attr6  attr7             from table1  table2  table3  etc  etc  etc  etc  etc             where etc etc etc etc etc etc etc etc etc etc etc etc etc           EOS    - gt   quot select    nfrom    nwhere    quot   If proper indentation is not a concern  then single and double quotes can span multiple lines in Ruby  conn exec  quot select attr1  attr2  attr3  attr4  attr5  attr6  attr7             from table1  table2  table3  etc  etc  etc  etc  etc              where etc etc etc etc etc etc etc etc etc etc etc etc etc quot         - gt   quot select    n           from    n           where    quot          If single or double quotes are cumbersome because that would need lots of escaping  then the percent string literal notation   is the most flexible solution  conn exec   select attr1  attr2  attr3  attr4  attr5  attr6  attr7             from table1  table2  table3  etc  etc  etc  etc  etc             where  ProductLine    R  OR ProductLine    quot S quot   AND Country    quot     quot     - gt   quot select    n            from    n            where    quot   If the aim is to avoid the newlines  which both the squiggly HEREDOC  quotes and the percent string literal will cause   then a line continuation can be used by putting a backslash   as the last non-whitespace character in a line  This will continue the line and will cause Ruby to concatenate the Strings back to back  watch out for those spaces inside the quoted string   conn exec  select attr1  attr2  attr3  attr4  attr5  attr6  attr7                from table1  table2  table3  etc  etc  etc  etc  etc                 where etc etc etc etc etc etc etc etc etc etc etc etc etc     - gt   quot select   from   where    quot   If you use Rails  then String squish will strip the string of leading and trailing space and collapse all consecutive whitespaces  newlines  tabs  and all  into a single space  conn exec  quot select attr1  attr2  attr3  attr4  attr5  attr6  attr7             from table1  table2  table3  etc  etc  etc  etc  etc              where etc etc etc etc etc etc etc etc etc etc etc etc etc quot  squish    - gt   quot select   attr7 from   etc  where    quot   More details  Ruby HEREDOC Syntax The Here Document Notation for Strings is a way to designate long blocks of text inline in code  It is started by  lt  lt  followed by a user-defined String  the End of String terminator   All following lines are concatenated until the End of String terminator is found at the very beginning of a line  puts  lt  lt HEREDOC  Text Text Text Text Bla Bla HEREDOC   - gt   quot Text Text Text Text nBlaBla quot   The End of String terminator can be chosen freely  but it is common to use something like  quot EOS quot   End of String  or something that matches the domain of the String such as  quot SQL quot   HEREDOC supports interpolation by default or when the EOS terminator is double quoted  price   10 print  lt  lt  quot EOS quot     comments can be put here 1   The price is   price   EOS   - gt   quot 1   The price is 10  quot   Interpolation can be disabled if the EOS terminator is single quoted  print  lt  lt  EOS    Disabled interpolation 3   The price is   price   EOS   - gt   quot 3   The price is   price   quot   One important restriction of the  lt  lt HEREDOC is that the End of String terminator needs to be at the beginning of the line    puts  lt  lt EOS      def foo       print  quot foo quot      end   EOS EOS  - gt   quot     def foo n      print  quot foo quot  n    end n  EOS quot   To get around this  the  lt  lt - syntax was created  It allows the EOS terminator to be indented to make the code look nicer  The lines between the  lt  lt - and EOS terminator are still used in their full extend including all indentation  def printExample   puts  lt  lt -EOS   Use  lt  lt - to indent End of String terminator     def foo       print  quot foo quot      end   EOS end   - gt   quot     def foo n      print  quot foo quot  n    end quot   Since Ruby 2 3  we now have the squiggly HEREDOC  lt  lt   removes leading whitespace  puts  lt  lt  EOS   Use the squiggly HEREDOC  lt  lt   to remove leading whitespace  since Ruby 2 3     def foo     print  quot foo quot    end EOS   - gt   quot def foo n  print  quot foo quot  nend quot   Empty lines and lines which only contains tabs and space are ignored by  lt  lt   puts  lt  lt  EOS inspect    Hello      World  EOS  - gt   quot Hello n  World  quot   If both tabs and spaces are used  tabs are considered as equal to 8 spaces  If the least-indented line is in the middle of a tab  this tab is not removed  puts  lt  lt  EOS inspect  lt tab gt One Tab  lt space gt  lt space gt Two Spaces EOS   - gt   quot  tOne Tab nTwoSpaces quot   HEREDOC can do some crazy stuff such as executing commands using backticks  puts  lt  lt  EOC              echo   price  echo   price   2  EOC  HEREDOC String definitions can be  quot stacked quot   which means that the first EOS terminator  EOSFOO below  will end the first string and start the second  EOSBAR below   print  lt  lt EOSFOO   lt  lt EOSBAR      you can stack them I said foo  EOSFOO I said bar  EOSBAR  I don t think anybody would ever use it as such  but the  lt  lt EOS is really just a string literal and can be put whereever a string can normally be put  def func a b c    puts a   puts b   puts c end  func  lt  lt THIS  23   lt  lt THAT   Here s a line or two  THIS and here s another  THAT  If you don t have Ruby 2 3  but Rails  gt   3 0 then you can use String strip heredoc which does the same as  lt  lt     File activesupport lib active support core ext string strip rb  line 22 class String   def strip heredoc     gsub     scan      t      S    min     quot  quot  freeze    end end  puts  lt  lt -USAGE strip heredoc   If no Ruby 2 3  but Rails  gt   3 0   This command does such and such     Supported options are      -h         This message         USAGE  Troubleshooting If you see errors when Ruby parses your file  then it is most likely that you either have extra leading or trailing spaces with a HEREDOC or extra trailing spaces with a squiggly HEREDOC  For example  What you see      database yml    lt  lt  EOS       production          database    fetch  user           adapter  postgresql         pool  5         timeout  5000     EOS    What Ruby tells you  SyntaxError      sample rb xx  can t find string  quot EOS quot  anywhere before EOF    sample rb xx  syntax error  unexpected end-of-input  expecting  end   What is at fault   Spot the extra spaces after the terminating EOS  Percent String Literals See RubyDoc for how to use the percentage sign followed by a string in a parentheses pair such as a                         etc  or a pair of any non-alphanumeric character such as        Last Words Last  to get the answer to the original question  quot Is there a way to imply concatenation  quot  answered  Ruby always implies concatenation if two strings  single and double quoted  are found back to back  puts  quot select    quot   from table      quot where    quot    - gt   quot select   from table   where    quot   The caveat is that this does not work across line-breaks  because Ruby is interpreting an end of statement and the consequitive line of just strings alone on a line doesn t do anything

User · Answer

conn exec  select attr1  attr2  attr3  attr4  attr5  attr6  attr7    lt  lt           from table1  table2  table3  etc  etc  etc  etc  etc     lt  lt           where etc etc etc etc etc etc etc etc etc etc etc etc etc     lt  lt  is the concatenation operator for strings

User · Answer

There are pieces to this answer that helped me get what I needed  easy multi-line concatenation WITHOUT extra whitespace   but since none of the actual answers had it  I m compiling them here   str    this is a multi-line string       using implicit concatenation       to prevent spare  n  s     gt   this is a multi-line string using implicit concatenation to eliminate spare   n s    As a bonus  here s a version using funny HEREDOC syntax  via this link    p  lt  lt END SQL gsub   s         strip SELECT   FROM     users          ORDER BY users id DESC END SQL    gt  gt   SELECT   FROM users ORDER BY users id DESC    The latter would mostly be for situations that required more flexibility in the processing  I personally don t like it  it puts the processing in a weird place w r t  the string  i e   in front of it  but using instance methods that usually come afterward   but it s there  Note that if you are indenting the last END SQL identifier  which is common  since this is probably inside a function or module   you will need to use the hyphenated syntax  that is  p  lt  lt -END SQL instead of p  lt  lt END SQL   Otherwise  the indenting whitespace causes the identifier to be interpreted as a continuation of the string   This doesn t save much typing  but it looks nicer than using   signs  to me   Also  I say in an edit  several years later   if you re using Ruby 2 3   the operator  lt  lt   is also available  which removes extra indentation from the final string  You should be able to remove the  gsub invocation  in that case  although it might depend on both the starting indentation and your final needs    EDIT  Adding one more   p    SELECT   FROM     users          ORDER BY users id DESC   gsub   s         strip    gt  gt   SELECT   FROM users ORDER BY users id DESC

[ruby] Ruby: Can I write multi-line string with no concatenation?

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