Programming idiom

In programming and in code, an idiom describes a commonly-used way to code a relatively small construct in a particular programming context (i.e. programming language). Many such constructs are found in multiple programming contexts yet tend to vary by context. Like a linguistic idiom, a programming idiom is a commonly-used way to express a concept in a language that exists outside the definition of the language yet is constrained by it.

Similar to a software design pattern, an idiom is a template to be followed; not code that can be copy-and-pasted into a codebase. In this sense, an idiom is a pattern, yet software design pattern is a classification reserved for significantly larger-scale functionality; usually involving the interaction of multiple objects.

Using the idioms for a programming context (instead of using idiosyncratic constructs) helps a team work together since they lower the cognitive load of the resulting code. Such idiomatic use is common in crowdsourced repositories to help developers overcome programming barriers.

Examples

Writing to standard output

Writing to standard output is generally something covered early when learning a language; often presented to the learner as a task to write a hello world program.

A common idiom in C++ like:

std::println("Hello World");

For Java:

System.out.println("Hello World");

For Rust:

println!("Hello World");

Using dynamic memory

In C, use the C dynamic memory allocation functions such as malloc() and free().

In C++, use the new and delete operators. The C dynamic memory allocation functions are usable in C++, but would generally be considered idiosyncratic.

See also

• Algorithmic skeleton
• Embedded SQL
• Idiom

External links

• programming-idioms.org shows short idioms implementations in most mainstream languages.
• C++ programming idioms from Wikibooks.