Parameter Utilities🔗 i

by Dave Herman and Sam Tobin-Hochstadt.

This library provides several utilities for parameters.

1Getting Started🔗 i

Everything in this library is exported by a single module:

(require parameter ) package: parameter

2Pseudo-Parameters🔗 i

A pseudo-parameter is like a Racket parameter, but comprises both an accessor and a mutator function. This can be used, for example, to create compound parameters that simultaneously update multiple parameters.

procedure
( make-pseudo-parameter gettersetter)→(pseudo-parameter/c a)
getter:(->a)
setter:(a->any)

Constructs a new pseudo-parameter with getter and setter functions.

procedure
( pseudo-parameter? x)→boolean?
x:any

Determines whether a given value is a pseudo-parameter.

procedure
( pseudo-parameter/c c)→contract?
c:contract?

A contract constructor for pseudo-parameters with an underlying value of contract c.

3Parameter Sets🔗 i

A parameter set is a collection of Racket parameters that can be read or written to all at once with a prefab structure. Because the structure is prefab, a parameter set can also easily be marshalled and demarshalled (assuming its values are all write able, of course).

syntax
( define-parameter-set struct-idpseudo-id
(param-iddefault-exprmaybe-guard)...)

maybe-guard =
| guard-expr

Defines a parameter set. The struct-id is defined as a prefab structure type with one field for each parameter in the set, in declaration order. The pseudo-id is defined as a pseudo-parameter that reads or writes the values of all the parameters in the set simultaneously. Each param-id is defined as a parameter with default value computed by default-expr and optional guard computed by maybe-guard.

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