Note: you shouldn't name your class Config because that's already a built-in class. If your app gets complicated enough to need multiple interacting services, you might need want to set up a kind of service registry that hold references to the services (google "dependency injection" for more info). Think of ConfigObject as a "service" used by other classes. $config = ConfigObject.new('/tmp/dir', 10)Ī similar technique uses class variables to accomplish the same thing: class ConfigObjectĬonfigObject.file_limit # use this somehow # it's a good idea to create this before everything else But if you need to modify the value, you can create a ConfigObject class to group these variables.Įxample: ConfigObject = Struct.new(:tmp_dir, :file_limit) The TMP_DIR solution will still work in this case. If the script becomes longer or more complex, you should refactor into classes. A local variable is only accessible within the block of its initialization. These variables are local to the code construct in which they are declared. freeze on the string to avoid accidental modification. Local Variables: A local variable name always starts with a lowercase letter (a-z) or underscore (). But if you don't need to modify it, you should use solution of a global constant like TMP_DIR. If that's the case, there's no reason you can't use a modifiable global variable like $tmp_dir. Global variable in Class1 is 10 Global variable in Class2 is 10 Ruby Instance Variables Instance variables begin with. This will produce the following result NOTE In Ruby, you CAN access value of any variable or constant by putting a hash () character just before that variable or constant. The $-W variable reflects the warning level of 0, 1, or 2, which may be set on the command line or by assigning $-W.It sounds like you're writing a short script. It is evident in our example that the contents variable is being shared between the reader and writer.But we can also manufacture multiple reader-writer pairs using box as defined above each pair shares a contents variable, and the pairs do not interfere with each other. Here globalvariable is a global variable. Strings can now be tagged individually with their encodings. Theyre denoted by beginning with a (dollar sign) character. $-K and $KCODE are not tagged as deprecated in Ruby 1.8, but nonetheless provoke a warning if used in Ruby 1.9, and have no effect. Global Variables are variables that may be accessed from anywhere in the program regardless of scope. Setting $= will provoke a warning and have no other effect. The $=, $defout, and $deferr variables, deprecated in Ruby 1.8, disappear altogether in Ruby 1.9. Level for taint and other security-related checks. Returns Process::Status for last executed child process (e.g., from `ls -l`)Īn array containing the filenames of modules loaded by require, read-only. True if debug mode is enabled (command line switch -d).Īrray containing the paths from which objects can be loaded. This may be set to "EUC-JP", "SJIS", "UTF8", "ASCII", or "NONE" to set which of the supported character encodings will be assumed. This variable is removed from Ruby 1.9 use str.force_encoding(enc) to set the encoding of an individual string. Unlike argv in a C program, $* does not include the name of the program that is found in $0. Numeric process ID of the current process.Īrray containing the command line parameters. $\ is set to the value of $/, and then each line read is processed using chop!. True if automatic line ending processing (command line switch -l). Item to be emitted between the parameters of print and Array#join. Rails automatically passes the controller's instance variables to the view context. In Ruby instance variables are declared with : class DemoController def index somevariable 'dlroW olleH' somevariable backwards end private def backwards somevariable.reverse end end. String methods such as each_line also use this variable. And it's not really what you are looking for. If this is nil, the whole file will be read at once. When $= is set to a true value, String comparisons map uppercase ASCII letters to lowercase. To do case-insensitive String compares, use str1.casecmp(str2). This variable is deprecated and has been removed from Ruby 1.9. The MatchData of the last Regexp match in the current scope. parenthesized groups in the last regular expression. The highest group matched by the last successful Regexp match. The string following the last Regexp match, or nil if the match failed. The string preceding the last Regexp match, or nil if the match failed. The complete String that matched the last Regexp, or nil if the match failed. These variables are locally scoped in spite of their initial $ character. The special variables in Ruby 1.8 are listed below, and grouped into categories of related variables.Ī String giving a message describing the pending exception this is the second parameter to a raise backtrace for the pending exception, as an Array of Strings.
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