Namewhile

Namewhile is a hypothetical programming construct described in discussions of language design and programming pedagogy. It is presented as a loop form that binds a name to the result of an expression at the start of each iteration, continuing while a continuation condition is satisfied. The idea is to merge binding and looping into a single, concise construct, potentially reducing boilerplate compared with separate binding followed by a test.

Semantics

At the beginning of each iteration, the loop evaluates a binding expression that yields either a value or an absence of value. If a value is produced and any optional predicate holds, the name is bound to that value for the body of the iteration; otherwise the loop terminates. The bound name is typically in scope only within the loop body. This design emphasizes immediate availability of the bound value for processing inside the loop while keeping the continuation logic compact.

Syntax

Namewhile is not standardized, and proposed forms vary. A representative illustrative pseudo-syntax is: namewhile x <- expr while cond do body end. In other proposals, namebinding may occur with patterns rather than simple names, or the continuation condition may be expressed as a guard. The exact syntax depends on the language or teaching material.

Examples

namewhile line <- read_line() while line != "" do

print(line)

end

This pattern resembles consuming a stream or generator with an inline binding of the produced value.

Relation to other constructs

Namewhile sits between for-each-style iteration and while loops, sharing the idea of binding the produced value to a named variable. It is akin to optional bindings or monadic comprehensions found in some languages, but remains a theoretical or experimental concept rather than a mainstream feature.

Status

There is no widely adopted implementation in major languages. It appears primarily in theoretical discussions, language-design exercises, and educational contexts.