7.8 Unit Utilities

函数
(unit? v) → boolean?
v : any/c

Returns #t if v is a unit, #f otherwise.

语法
(provide-signature-elements sig-spec ...)

Expands to a provide of all identifiers implied by the sig-specs. See unit for the grammar of sig-spec.

1	Language Model
2	Notation for Documentation
3	Syntactic Forms
4	Datatypes
5	Structures
6	Classes and Objects
7	Units
8	Contracts
9	Pattern Matching
10	Control Flow
11	Concurrency and Parallelism
12	Macros
13	Input and Output
14	Reflection and Security
15	Operating System
16	Memory Management
17	Unsafe Operations
18	Running Racket
	Bibliography
	Index

7.1	Creating Units
7.2	Invoking Units
7.3	Linking Units and Creating Compound Units
7.4	Inferred Linking
7.5	Generating A Unit from Context
7.6	Structural Matching
7.7	Extending the Syntax of Signatures
7.8	Unit Utilities
7.9	Unit Contracts
7.10	Single-Unit Modules
7.11	Single-Signature Modules
7.12	Transformer Helpers