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 miscellaneous syntax
do: Starts a block.
else: The unhandled condition in case, if and unless expressions. See control expressions syntax
elsif: An alternate condition for an if expression. See control expressions syntax
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 exceptions syntax
false: Boolean false. See literals
for: A loop that is similar to using the each method. See control expressions syntax
if: Used for if and modifier if statements. See control expressions syntax
in: Used to separate the iterable object and iterator variable in a for loop. See control expressions syntax It also serves as a pattern in a case expression. See pattern matching
module: Creates or opens a module. See modules and classes syntax
next: Skips the rest of the block. See control expressions syntax
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 syntax
rescue: Starts an exception section of code in a begin block. See exceptions syntax
retry: Retries an exception block. See exceptions syntax
return: Exits a method. See methods syntax. If met in top-level scope, immediately stops interpretation of the current file.
self: The object the current method is attached to. See methods syntax
super: Calls the current method in a superclass. See methods syntax
then: Indicates the end of conditional blocks in control structures. See control expressions syntax
true: Boolean true. See literals
undef: Prevents a class or module from responding to a method call. See modules and classes syntax
unless: Used for unless and modifier unless statements. See control expressions syntax
until: Creates a loop that executes until the condition is true. See control expressions syntax
when: A condition in a case expression. See control expressions syntax
while: Creates a loop that executes while the condition is true. See control expressions syntax
yield: Starts execution of the block sent to the current method. See methods syntax