Keywords

The following keywords are used by Ruby.

  • __ENCODING__: The script encoding of the current file. See Encoding.

  • __LINE__: The line number of this keyword in the current file.

  • __FILE__: The path to the current file.

  • BEGIN: Runs before any other code in the current file. See miscellaneous syntax

  • END: Runs after any other code in the current file. See miscellaneous syntax

  • alias: Creates an alias between two methods (and other things). See modules and classes syntax

  • and: Short-circuit Boolean and with lower precedence than &&

  • begin: Starts an exception handling block. See exceptions syntax

  • break: Leaves a block early. See control expressions syntax

  • case: Starts a case expression. See control expressions syntax

  • class: Creates or opens a class. See modules and classes syntax

  • def: Defines a method. See methods syntax

  • defined?: Returns a string describing its argument. See defined?

  • do: Starts a block.

  • else: The unhandled condition in case, if and unless expressions. See control expressions

  • elsif: An alternate condition for an if expression. See control expressions

  • end: The end of a syntax block. Used by classes, modules, methods, exception handling and control expressions.

  • ensure: Starts a section of code that is always run when an exception is raised. See exception handling

  • false: Boolean false. See literals

  • for: A loop that is similar to using the each method. See control expressions

  • if: Used for if and modifier if expressions. See control expressions

  • in: Used to separate the iterable object and iterator variable in a for loop. See control expressions

  • module: Creates or opens a module. See modules and classes syntax

  • next: Skips the rest of the block. See control expressions

  • nil: A false value usually indicating “no value” or “unknown”. See literals

  • not: Inverts the following boolean expression. Has a lower precedence than !

  • or: Boolean or with lower precedence than ||

  • redo: Restarts execution in the current block. See control expressions

  • rescue: Starts an exception section of code in a begin block. See exception handling

  • retry: Retries an exception block. See exception handling

  • return: Exits a method. See methods

  • self: The object the current method is attached to. See methods

  • super: Calls the current method in a superclass. See methods

  • then: Indicates the end of conditional blocks in control structures. See control expressions

  • true: Boolean true. See literals

  • undef: Prevents a class or module from responding to a method call. See modules and classes

  • unless: Used for unless and modifier unless expressions. See control expressions

  • until: Creates a loop that executes until the condition is true. See control expressions

  • when: A condition in a case expression. See control expressions

  • while: Creates a loop that executes while the condition is true. See control expressions

  • yield: Starts execution of the block sent to the current method. See methods