Literal
A literal is a language construct that directly denotes a fixed value or specifies an exact value permitted by a type.
Modern C, Third Edition
A literal is source text that denotes a fixed value directly in a C program.
- How it is used
- Identifies fixed values written directly in C source and distinguishes them from identifiers that name program entities.
- How deep it goes
- Works through numeric bases, exponent forms, character and string notation, and type-dependent examples; does not develop literal parsing internals.
- Examples
- Compares `077` with 63, `0b1010` with 10, and `strtoul("0b1", nullptr, 2)` across C17 and C23.
- What you can do after
- Evaluate/understand it by reading common C literal forms and recognizing when type or string-conversion rules change their interpretation.
Modern C
A literal is a C source notation that directly represents a fixed value.
- How it is used
- Identifies fixed values written in C code and supplies integer values for preprocessor platform checks.
- How deep it goes
- Defines literals, compares numeric spellings, and works through sign and integer-type rules without developing all type-selection cases.
- Examples
- Uses decimal, octal, and hexadecimal constants, adjacent strings passed to `puts`, and a table comparing integer types and negated values.
- What you can do after
- Evaluate/understand literal spellings, distinguish negation from a numerical literal, and determine a decimal integer literal’s first fitting signed type.
Clojure: The Essential Reference
A compile-time literal is a fixed Clojure value recognized by the compiler without evaluating an expression to obtain it.
- How it is used
- Provides fixed branch tests for fast conditional selection with `case`.
- How deep it goes
- Defines accepted test forms and explains why expression-shaped tests are not evaluated, including duplicate-test and missing-default errors.
- Examples
- Uses numeric branches, expression-shaped tests, quoted-symbol collisions, and grouped operator names.
- What you can do after
- Apply it via `case` to choose valid constant tests and avoid mistaking expressions for evaluated tests.
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Rust in Action: Systems programming concepts and techniques
A literal form is Rust syntax that directly initializes or denotes a value according to the type's literal representation.
- How it is used
- Uses literal syntax to supply values for variable bindings and initialize a complex number’s fields.
- How deep it goes
- Explains numeric suffixes, separators, integer bases, and field initialization through examples rather than a complete literal-syntax reference.
- Examples
- Compares binary, octal, and hexadecimal integers, then initializes complex numbers with fields and `Complex::new()`.
- What you can do after
- Apply it via the `num` crate to initialize a complex value with field syntax or `Complex::new()`.
Read how Rust in Action: Systems programming concepts and techniques explains literal →
Learn SQL in a Month of Lunches
A literal value is a fixed constant written directly in an SQL statement rather than retrieved from a column or calculated dynamically.
- How it is used
- Uses fixed values to assign variables, label UNION rows, pass procedure arguments, and establish column defaults.
- How deep it goes
- Defines literals and demonstrates them in SELECT, UNION, defaults, and procedure calls, but does not develop formal expression theory.
- Examples
- Demonstrates date assignment, customer and author labels, the argument 1049, and a shipment-date default.
- What you can do after
- Apply it via SELECT, UNION, DEFAULT constraints, and stored-procedure calls when a known value belongs directly in SQL.
Julia as a Second Language
A number literal is a source-code notation that directly represents a numeric value with digits rather than a variable name.
- How it is used
- Represents numeric values directly in Julia source while selecting or signaling their numeric type.
- How deep it goes
- Defines numeric notation, demonstrates inferred types and suffixes, and briefly extends literals through macros without teaching macro internals.
- Examples
- Uses decimal, hexadecimal, rational, Float32, Float16, BigInt, and custom Int8 literal examples inspected in the REPL.
- What you can do after
- Apply it to write numeric values, inspect their types, choose conversions, and avoid confusing floating-point suffixes with multiplication.
Related concepts
- typing moduleused by · The typing module is a Python standard-library module that provides constructs for expressing and inspecting type annotations.
- variablecontrasts with · A variable is a named program binding or entity associated with a value that can be accessed and, when permitted, changed during computation.
- decimal literalincludes · A decimal literal is a numeric literal written with digits representing a number in base ten.
- octal literalincludes · An octal literal is an integer literal representing a value in base eight.
- C23produced by · C23 is the ISO standard revision of the C programming language published in 2024.
- selectused by · SELECT is a SQL query construct that specifies the rows, columns, or expressions retrieved from one or more queryable data sources.
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