► |  | Reference: PLT Scheme

1 | Language Model
2 | Syntactic Forms
3 | Datatypes
4 | Structures
5 | Classes and Objects
6 | Units
7 | Contracts
8 | Pattern Matching
9 | Control Flow
10 | Concurrency
11 | Macros
12 | Input and Output
13 | Reflection and Security
14 | Operating System
15 | Memory Management
16 | Running PLT Scheme
| Bibliography
| Index

▼ | 2 | Syntactic Forms

2.1 | Modules: module, ...
2.2 | Importing and Exporting: require and provide
2.3 | Literals: quote and #%datum
2.4 | Expression Wrapper: #%expression
2.5 | Variable References and #%top
2.6 | Locations: #%variable-reference
2.7 | Procedure Applications and #%app
2.8 | Procedure Expressions: lambda and case-lambda
2.9 | Local Binding: let, let*, letrec, ...
2.10 | Local Definitions: local
2.11 | Constructing Graphs: shared
2.12 | Conditionals: if, cond, and, and or
2.13 | Dispatch: case
2.14 | Definitions: define, define-syntax, ...
2.15 | Sequencing: begin, begin0, and begin-for-syntax
2.16 | Guarded Evaluation: when and unless
2.17 | Assignment: set! and set!-values
2.18 | Iterations and Comprehensions: for, for/ list, ...
2.19 | Continuation Marks: with-continuation-mark
2.20 | Quasiquoting: quasiquote, unquote, and unquote-splicing
2.21 | Syntax Quoting: quote-syntax
2.22 | Interaction Wrapper: #%top-interaction
2.23 | Limiting Scope: define-package, open-package, ...
2.24 | Flattening Syntactic Sequences: nest

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#%variable-reference

Version: 4.1.4
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#### 2.6`` Locations: #%variable-reference

(#%variable-reference id)
(#%variable-reference (#%top . id))
(#%variable-reference)

Produces an opaque variable reference value representing the location of id, which must be bound as a top-level variable or module-level variable. If no id is supplied, the resulting value refers to an “anonymous” variable defined within the enclosing context (i.e., within the enclosing module, or at the top level if the form is not inside a module).

A variable reference can be used with variable-reference->empty-namespace, variable-reference->resolved-module-path, and variable-reference->top-level-namespace, but facilities like define-namespace-anchor and namespace-anchor->namespace wrap those to provide an clearer interface. A variable reference is also useful to low-level extensions; see Inside: PLT Scheme C API.

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