Glossary

This glossary provides a list of key terms and concepts related to the Mojo programming language, along with the locations in the Miji where they are discussed.

Term and concept	Comments
variable
identifier	A symbolic name that refers to a value in the program.
uninitialized variable	A variable that has been declared but not yet assigned a value.
dunder method	A method whose name starts and ends with double underscores, e.g., __xxxx__(), used for special operations in Mojo.
shadowing	To declare a new variable with the same name as an existing one, effectively overwriting the original variable.
R-value and L-value	A value can be either an r-value or an l-value depending on their behaviors on the memory.
constructor	A special method that initializes a new instance of a specific type.
offset	The distance between the start of a data structure and a specific field within it, measured in the byte size of the data type (not the raw byte).
type checker	A tool in Python that statically checks the types of variables and expressions, and will warn you if there are type mismatches.
reference	An alias (body double) of a variable that allows access to the original variable without copying it.
safe pointer	A type that holds the address of a value in memory and the lifetime information of the owner. It is guaranteed to be safe to dereference.
Unsafe pointer	A type that holds an address in memory. You can de-reference it to access the value at that address.
overloading	To declare multiple functions with the same name but different arguments.
uninitialized	A variable that has been declared but not yet assigned a value.
compile time	The period when the Mojo code is translated into machine code.
run time	The period when the compiled code is executed.
dereferencing operator	An operator that accesses the value of a pointer. It is [] in Mojo.