Why Can't I Define Constant Maps in Golang?

Why Constants Lack Maps in Golang

In Golang, defining constant maps is prohibited. Attempts to create them result in the error "const initializer map[string]string literal is not a constant." This restriction stems from Golang's constant value definition guidelines.

According to the language specification, constant values can be represented by:

• Primitive data types (rune, integer, floating-point, imaginary, string)
• Identifiers denoting constants
• Constant expressions
• Built-in functions applied to values (e.g., unsafe.Sizeof, cap, len)

Noticeably absent from this list are composite types like arrays, slices, and maps. These types cannot be constants because they are not fundamentally numeric in nature. Constants must be immutable and have a static value that can be determined at compile-time, whereas composite types can change their values at runtime. Consequently, maps cannot be defined as constants in Golang.

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