From 333a909385ce5b2e6d5965adb62f4935bbf861ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Georges=20Dup=C3=A9ron?= <georges.duperon@gmail.com>
Date: Wed, 18 Nov 2015 15:26:55 +0100
Subject: [PATCH] Started writing fold-queues module, which can process
 multiple queues with distinct types.

---
 graph/graph/fold-queues.lp2.rkt | 97 +++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 graph/graph/fold-queues.lp2.rkt

diff --git a/graph/graph/fold-queues.lp2.rkt b/graph/graph/fold-queues.lp2.rkt
new file mode 100644
index 00000000..bddf6ce5
--- /dev/null
+++ b/graph/graph/fold-queues.lp2.rkt
@@ -0,0 +1,97 @@
+#lang debug scribble/lp2
+@(require "../lib/doc.rkt")
+@doc-lib-setup
+
+@title[#:style manual-doc-style]{The queue library}
+
+@(table-of-contents)
+
+@section{Introduction}
+
+@section{Implementation}
+
+@chunk[<fold-queues-signature>
+       (fold-queues root-value
+                    [(name [element (~literal :) element-type] Δ-queues get-tag)
+                     (~literal :) result-type
+                     . body]
+                    ...)]
+
+@chunk[<define-enqueue-type>
+       (define/with-syntax get-tag/type
+         #'(∀ (X) (case→ (→ 'name element-type X (values Index X))
+                         ...)))]
+
+@chunk[<define-Δ-queues-type>
+       (define/with-syntax queues/type
+         #'(List (Δ-Hash element-type Index) ...))]
+
+@chunk[<fold-queue-multi-sets-immutable-tags>
+       (define-syntax/parse <fold-queues-signature>
+         <define-enqueue-type>
+         <define-Δ-queues-type>
+         #'(list (λ ([element : element-type]
+                     [get-tag : get-tag/type]
+                     [Δ-queues : queues/type])
+                   : result-type
+                   . body)
+                 ...)
+         #;#'(error "Not implemented yet"))]
+
+
+@tc[Δ-Hash] is a type encapsulating both a hash, and a set of key-value pairs
+added to the @tc[Δ-Hash] since its creation from a simple @tc[HashTable].
+
+@chunk[<Δ-hash>
+       (define-type (Δ-Hash A B)
+         (Pairof (HashTable A B)
+                 (Setof (Pairof A B))))
+       
+       (: empty-Δ-hash (∀ (K V) (→ (Δ-Hash K V))))
+       (define (empty-Δ-hash)
+         (cons ((inst hash K V)) ((inst set (Pairof K V)))))
+       
+       (: Δ-hash (∀ (K V) (→ (HashTable K V) (Δ-Hash K V))))
+       (define (Δ-hash h)
+         (cons h ((inst set (Pairof K V)))))
+       
+       (: Δ-hash-add (∀ (K V) (→ (Δ-Hash K V) K V
+                                 (Δ-Hash K V))))
+       (define (Δ-hash-add dh k v)
+         (if (hash-has-key? (car dh) k)
+             dh
+             (cons (hash-set (car dh) k v)
+                   (set-add (cdr dh) (cons k v)))))]
+
+@section{Conclusion}
+
+@chunk[<module-main>
+       (module main typed/racket
+         (require (for-syntax syntax/parse
+                              racket/syntax
+                              "../lib/low-untyped.rkt")
+                  "../lib/low.rkt")
+         
+         (provide fold-queues)
+         
+         <Δ-hash>
+         <fold-queue-multi-sets-immutable-tags>)]
+
+@chunk[<module-test>
+       (module* test typed/racket
+         (require (submod "..")
+                  typed/rackunit)
+         
+         ; TODO
+         
+         (require (submod ".." doc)))]
+
+@chunk[<*>
+       (begin
+         <module-main>
+         
+         (require 'main)
+         (provide (all-from-out 'main))
+         
+         <module-test>)]
+