The following list contains keywords that are reserved for current or future use by the Sway language. As such, they cannot be used as identifiers. Identifiers are names of functions, variables, parameters, modules, constants, attributes, types or traits, etc.
The following is a list of keywords currently in use, with their functionality described.
as - rename items in use statements, e.g., use type::a as alias_name abi - defines a smart contract ABI in a syntactically similar way to traits break - exit a loop immediately const - define constant items continue - continue to the next loop iteration else - used in conjunction with if conditions for control flow constructs enum - define an enumeration false - Boolean false literal fn - define a function or the function pointer type if - branch based on the result of a conditional expression impl - implement inherent or trait functionality let - bind a variable match - exhaustively match a value to patterns mod - define a module mut - denote mutability in references, or pattern bindings pub - denote public visibility of Sway data structures, traits, or modules ref - bind by reference return - return early from a function Self - a type alias for the type we are defining or implementing self - method subject struct - define a structure trait - define a trait true - Boolean true literal type - define a type alias or associated type use - bring symbols into scope where - specifies traits for generic types while - loop conditionally based on the result of an expression abstract async await become box do dyn extern for in loop macro move override priv static super try typeof unsafe unsized virtual yield Keywords associated with defining the type of Sway program to compile
contract - analogous to a deployed API with some database state library - Sway code that defines new common behavior predicate - programs that return a Boolean value and which represent ownership of some resource upon execution to true script - a runnable bytecode on the chain, which executes once to perform a task Keywords associated with defining the functionality of attributes
allow - overrides checks that would otherwise result in errors or warnings doc - specifies documentation inline - suggests that a copy of the attributed function should be placed in the caller, rather than generating code to call the function where it is defined payable - implies method is payable for compile time storage - declaration that contains a list of stored variables test - marks a function to be executed as a test deprecated - marks an item as deprecated