From e200e606900328bea1c237287d55ccd1f2b3ff2f Mon Sep 17 00:00:00 2001
From: Arun Isaac
Date: Sat, 14 Oct 2023 23:38:58 +0100
Subject: Use list-transduce.

list-transduce allows us to see desired house listings as soon as they
are found. We don't have to wait until all desired house listings are
processed.

* rent.scm (main): Use list-transduce.
---
 rent.scm | 41 +++++++++++++++++++++++------------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/rent.scm b/rent.scm
index 64ec3e0..6b64245 100644
--- a/rent.scm
+++ b/rent.scm
@@ -23,6 +23,7 @@
              (srfi srfi-26)
              (srfi srfi-71)
              (srfi srfi-43)
+             (srfi srfi-171)
              (ice-9 match)
              (ice-9 regex)
              (ice-9 string-fun)
@@ -460,21 +461,25 @@ Cycling distance to Wembley stadium: ~,1f km
 ;; - there is at least one tube station in the vicinity
 ;; - is not a bedsit
 ;;
-;; Sort the listed houses newest advertisments last.
-(list-houses
- (filter (lambda (house)
-           (and (not (house-bills-included? house))
-                (< (house-hours-live house) 100)
-                (not (house-shared? house))
-                (<= (house-bedrooms house) 1)
-                (>= (house-rent house) 1200)
-                (<= (house-rent house) 1400)
-                (house-unfurnished? house)
-                (house-live? house)
-                (>= (house-maximum-tenants house) 2)
-                (not (null? (house-tube-stations house)))
-                (not (string-contains-ci (house-title house) "bedsit"))))
-         (sort (all-houses)
-               (lambda (house1 house2)
-                 (> (house-hours-live house1)
-                    (house-hours-live house2))))))
+;; Sort the listed houses newest advertisments first.
+(format (current-output-port)
+        "~a houses~%"
+        (list-transduce (compose (tfilter (lambda (house)
+                                            (and (not (house-bills-included? house))
+                                                 (< (house-hours-live house) 100)
+                                                 (not (house-shared? house))
+                                                 (<= (house-bedrooms house) 1)
+                                                 (>= (house-rent house) 1200)
+                                                 (<= (house-rent house) 1400)
+                                                 (house-unfurnished? house)
+                                                 (house-live? house)
+                                                 (>= (house-maximum-tenants house) 2)
+                                                 (not (null? (house-tube-stations house)))
+                                                 (not (string-contains-ci (house-title house) "bedsit")))))
+                                 (tlog (lambda (_ house)
+                                         (list-house house))))
+                        rcount
+                        (sort (all-houses)
+                              (lambda (house1 house2)
+                                (< (house-hours-live house1)
+                                   (house-hours-live house2))))))
-- 
cgit v1.2.3