https://github.com/suzannesoy/remember

Compile-time memoization for Racket.
https://github.com/suzannesoy/remember

macros memoization racket-library

Last synced: 6 months ago
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Compile-time memoization for Racket.

• Host: GitHub
• URL: https://github.com/suzannesoy/remember
• Owner: SuzanneSoy
• License: cc0-1.0
• Created: 2016-05-28T22:38:32.000Z (about 10 years ago)
• Default Branch: main
• Last Pushed: 2021-04-04T14:29:00.000Z (about 5 years ago)
• Last Synced: 2025-01-30T11:42:09.723Z (over 1 year ago)
• Topics: macros, memoization, racket-library
• Language: Racket
• Homepage: http://docs.racket-lang.org/remember/
• Size: 19.5 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE-more.md

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remember

========

This Racket library provides a compile-time memoize feature. It allows

remembering a value with `(remember-write! 'category 'value)`. In subsequent

compilations, `(get-remembered 'category)` will return a set of all

previously-remembered values.

Installation

============

raco pkg install remember

Example use case: the `phc-adt` library

=======================================

This library is used to implement "interned" structure and constructor types

in the [`phc-adt`](https://github.com/jsmaniac/phc-adt) library. The `phc-adt`

library needs to know the set of all structure and constructor types used in

the program, and uses `remember` to automatically memoize structure

descriptors and constructor names.

When the `structure` macro defined in

[`structure.hl.rkt`](https://github.com/jsmaniac/phc-adt/blob/refactor/structure.hl.rkt)

encounters an unknown list of field names, it uses the `remember` library to

append the tuple of field names to a user-specified file. That file is loaded

in subsequent compilations, so that the tuple of fields is known to `phc-adt`.

The memoized descriptors are used to know all possible structs that can

contain a field with the desired name when accessing it with `(get instance

field-name)`. The `get` macro can then retrieve the field's value using the

right accessor (for example `(struct123-fieldname instance)`). Knowing all

existing structures allows `get` to perform some kind of dynamic dispatch to

obtain the appropriate accessor, for example using a `cond` which tests for

all possible types.

The `constructor` macro defined in

[`constructor.hl.rkt`](https://github.com/jsmaniac/phc-adt/blob/refactor/constructor.hl.rkt)

works in the same way, but remembers the name of the constructor's tag instead

of field names. The memoization feature is used so that all uses of a

constructor with a given name are equivalent, across all files.