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
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unit/ new-import-export
define-unit/ new-import-export
Version: 4.0.2

 

6.6 Structural Matching

(unit/new-import-export

  (import tagged-sig-spec ...)

  (export tagged-sig-spec ...)

  init-depends-decl

  ((tagged-sig-spec ...) unit-expr tagged-sig-spec))

Similar to unit, except the body of the unit is determined by an existing unit produced by unit-expr. The result is a unit that whose implementation is unit-expr, but whose imports, exports, and initialization dependencies are as in the unit/new-import-export form (instead of as in the unit produced by unit-expr).

The final clause of the unit/new-import-export form determines the connection between the old and new imports and exports. The connection is similar to the way that compound-unit propagates imports and exports; the difference is that the connection between import and the right-hand side of the link clause is based on the names of elements in signatures, rather than the names of the signatures. That is, a tagged-sig-spec on the right-hand side of the link clause need not apppear as a tagged-sig-spec in the import clause, but each of the bindings implied by the linking tagged-sig-spec must be implied by some tagged-sig-spec in the import clause. Similarly, each of the bindings implied by an export tagged-sig-spec must be implied by some left-hand-side tagged-sig-spec in the linking clause.

(define-unit/new-import-export unit-id

  (import tagged-sig-spec ...)

  (export tagged-sig-spec ...)

  init-depends-decl

  ((tagged-sig-spec ...) unit-expr tagged-sig-spec))

Like unit/new-import-export, but binds static information to unit-id like define-unit.