Display
Display is Rust’s standard formatting trait for producing a user-facing textual representation of a value.
Refactoring to Rust
The Display trait is Rust's formatting trait for producing a user-facing textual representation of a value.
- How it is used
- Centralizes user-facing calculator error messages so callers can print specific errors with {}.
- How deep it goes
- Works through fmt, Formatter, write!, variant matching, and the updated error-printing call.
- Examples
- Uses a hello-world Display implementation and calculator errors for invalid input and an empty stack.
- What you can do after
- Apply it via std::fmt to define reusable error messages and print them with eprintln!.
Learn Rust in a Month of Lunches
Display printing formats a Rust value using its user-facing Display formatting behavior.
- How it is used
- Formats values for readable `println!` output and lets custom types control the wording shown to users.
- How deep it goes
- Moves from `{}` and compiler feedback to a worked `Display` implementation; leaves some `Formatter` syntax unexplained.
- Examples
- Uses a failed attempt to print `()`, a custom `Cat` sentence, and cleaner article-application output.
- What you can do after
- Build it from scratch for a struct, then print it with `{}` or turn its output into a `String`.
Read how Learn Rust in a Month of Lunches explains Display →
Rust in Action: Systems programming concepts and techniques
The Display trait is Rust's standard formatting trait for producing a user-facing textual representation of a value.
- How it is used
- Formats custom values for console output, strings, formatted writers, and user-facing error messages.
- How deep it goes
- Defines the fmt contract and demonstrates nested implementations, but leaves Formatter details largely unexplored.
- Examples
- Uses File and FileState formatting plus an UpstreamError enum that reuses Debug output.
- What you can do after
- Build it from scratch by implementing Display for structs, enums, nested fields, and wrapper error types.
Read how Rust in Action: Systems programming concepts and techniques explains Display →
Related concepts
- println! macroused by · The println! macro is an output operation that formats arguments and writes the resulting text followed by a line terminator to standard output.
- traitkind of · A trait is a type-level construct that defines reusable behavior or members that types can implement or compose.
- toStringproduces · toString is a method or trait operation that returns a textual representation of a value or object.
- slicingimplemented by · Slicing selects or partitions a portion of an indexed sequence or multidimensional array, often along specified indices or dimensions.
- use declarationused by · A use declaration is Rust syntax that brings names or items from a module or crate into scope for unqualified access.
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