Nuts and bolts

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| Ruby user's guide | Nuts and bolts |

This chapter addresses a few practical issues.

### Statement delimiters

Some languages require some kind of punctuation, often a semicolon (`;`), to end each statement in a program. Ruby instead follows the convention used in shells like `sh` and `csh`. Multiple statements on one line must be separated by semicolons, but they are not required at the end of a line; a linefeed is treated like a semicolon. If a line ends with a backslash (`\`), the linefeed following it is ignored; this allows you to have a single logical line that spans several lines.

### Comments

Why write comments? Although well written code tends to be self-documenting, it is often helpful to scribble in the margins, and it can be a mistake to believe that others will be able to look at your code and immediately see it the way you do. Besides, for practical purposes, you yourself are a different person within a few days anyway; which of us hasn't gone back to fix or enhance a program after the passage of time and said, I know I wrote this, but what in blazes does it mean?

Some experienced programmers will point out, quite correctly, that contradictory or outdated comments can be worse than none at all. Certainly, comments shouldn't be a substitute for readable code; if your code is unclear, it's probably also buggy. You may find that you need to comment more while you are learning ruby, and then less as you become better at expressing your ideas in simple, elegant, readable code.

Ruby follows a common scripting convention, which is to use a pound symbol (`#`) to denote the start of a comment. Anything following an unquoted `#`, to the end of the line on which it appears, is ignored by the interpreter.

Also, to facilitate large comment blocks, the ruby interpreter also ignores anything between a line starting with "`=begin`" and another line starting with "`=end`".

    #!/usr/bin/env ruby

    =begin
    **********************************************************************
      This is a comment block, something you write for the benefit of
      human readers (including yourself).  The interpreter ignores it.
      There is no need for a '#' at the start of every line.
    **********************************************************************
    =end

### Organizing your code

The ruby interpreter processes code as it reads it. There is nothing like a compilation phase; if something hasn't been read yet, it is