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Why do I need brackets in Ruby ... or Perl, Python, C or Java

In many languages, you're required to put brackets around the boolean condition in your if and while statements, and around parameters you're passing to functions. And it becomes the natural way of coding for programmers in languages like Java, C and C++. But when you think about it, those brackets may be redundant syntax. What are brackets really used for?

Brackets are used to group things together. To say "do this first" if you want to override the BODMAS / BIDMAS precedence (Brackets, order/indeces, division, multiplication, addition, subtraction), and to evaluate all the parameters to a function before the function itself is called.

So --- if there is no ambiguity or precedence issue ---, it's logical that you can leave out the brackets. That's the case with Ruby ... and partially the case in Perl. Here's a Ruby example:

puts((puts "a") , (puts "b"))
puts "-----------"
puts "c", "d"


In the first line, there are brackets because there's a need to group the text strings with the appropriate puts, but in the other lines there isn't any precedence issue, and so the brackets have been dropped. See how it runs:

wizard:r11 graham$ ruby demo
a
b
nil
nil
-----------
c
d
wizard:r11 graham$


In some languages - such as Python - brackets after a function name have a somewhat different meaning - they actually instruct the language to run the code held in the variable rather than simply return a string about it:

def copyr():
  print "This is mine"
  return "empty bottle"
a = copyr
b = copyr()
print a,b


And that runs as follows:

wizard:r11 graham$ python pyrex
This is mine
<function copyr at 0x100475c08> empty bottle
wizard:r11 graham$

(written 2010-09-29)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
R104 - Ruby - Control Structures
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  [4504] Where does Ruby load modules from, and how to load from current directory - (2015-06-03)
  [4503] Separating your code for easier testing, understanding and re-use; example in Ruby - (2015-06-02)
  [4402] Finding sum, minimum, maximum and average in Python (and Ruby) - (2015-01-19)
  [4370] Conditionals, loops and methods in Ruby - a primer with simple examples - (2014-12-29)
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  [3769] Muttable v immutable and implications - Ruby - (2012-06-20)
  [3620] Finding the total, average, minimum and maximum in a program - (2012-02-22)
  [3619] Ruby v Perl - a comparison example - (2012-02-21)
  [3422] Assigning values to variables within other statements - Ruby - (2011-09-07)
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  [3254] Multiple inputs, multiple out, ruby functions - (2011-04-19)
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  [3200] How a for loop works Java, Perl and other languages - (2011-03-12)
  [3159] Returning multiple values from a function call in various languages - a comparison - (2011-02-06)
  [3158] Ruby training - some fresh examples for string handling applications - (2011-02-05)
  [3156] Splitting data reading code from data processing code - Ruby - (2011-02-04)
  [2892] Alternative loops and conditionals in Ruby and Perl - (2010-07-28)
  [2711] For loop - checked once, or evety time? Ruby v Perl comparison and contrast - (2010-04-07)
  [2619] Passing code to procedures and yield in Ruby - (2010-02-02)
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  [1891] Ruby to access web services - (2008-11-16)
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  [1738] Clean code, jump free (Example in Lua) - (2008-08-06)
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  [1587] Some Ruby programming examples from our course - (2008-03-21)
  [1582] Ruby, C, Java and more - getting out of loops - (2008-03-19)
  [1220] for loop - how it works (Perl, PHP, Java, C, etc) - (2007-06-06)
  [1163] A better alternative to cutting and pasting code - (2007-04-26)
  [995] Ruby's case - no break - (2006-12-17)
  [985] Equality in Ruby - == eql? and equal? - (2006-12-14)
  [962] Breaking a loop - Ruby and other languages - (2006-12-03)
  [960] 1st, 2nd, 3rd revisited in Ruby - (2006-12-02)


Back to
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Creating, extending, traversing and combining Ruby arrays
Some other Articles
Ruby - yield; parallel routines
Christmas 2010 - Well House Manor, Melksham, Hotel
What is a factory method and why use one? - Example in Ruby
Creating, extending, traversing and combining Ruby arrays
Why do I need brackets in Ruby ... or Perl, Python, C or Java
Formatting your output - options available in Ruby
Learning to program - where to start if you have never programmed before
Some more advanced Perl examples from a recent course
Should the public sector compete with businesses? and other deep questions
Perl - doing several things at the same time
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