From a8653d4974f105c16bd0a21d8f405b6c3adf7ec3 Mon Sep 17 00:00:00 2001
From: Sean Corfield <sean@corfield.org>
Date: Fri, 30 May 2025 14:46:06 -0400
Subject: [PATCH] start of looking at transducers

Signed-off-by: Sean Corfield <sean@corfield.org>
---
 .gitignore                         |  3 +++
 notebooks/clojure_camp/pairing.clj | 42 ++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 notebooks/clojure_camp/pairing.clj

diff --git a/.gitignore b/.gitignore
index 91650535..df065b8c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,6 @@ _site/
 /checkouts
 /classes
 /target
+.calva/repl.calva-repl
+.calva/mcp-server/port
+.portal/vs-code.edn
diff --git a/notebooks/clojure_camp/pairing.clj b/notebooks/clojure_camp/pairing.clj
new file mode 100644
index 00000000..df9207cd
--- /dev/null
+++ b/notebooks/clojure_camp/pairing.clj
@@ -0,0 +1,42 @@
+
+(ns clojure-camp.pairing)
+
+;; let's work on an algorithm together!
+
+;; this produces a lazy sequence of strings:
+(map #(str "Hello, " % "!") ["Alice" "Bob" "Charlie"])
+
+;; here's the non-lazy transducer-based version:
+(into []
+      (map #(str "Hello, " % "!"))
+      ["Alice" "Bob" "Charlie"])
+
+;; map with a single function argument produces a transducer:
+(map #(str "Hello, " % "!"))
+
+;; we can build up xforms (transformers) using the `comp` function:
+(def xf (comp (filter #(> (count %) 3))
+              (map #(str "Hello, " % "!"))))
+
+;; and now use it with `into`:
+(into []
+      xf ; Bob gets filtered out
+      ["Alice" "Bob" "Charlie"])
+
+;; "traditional" SQL-like rows of columns:
+^:kind/table
+[{:name "Alice" :age 30 :city "Wonderland"}
+ {:name "Bob" :age 25 :city "Builderland"}
+ {:name "Charlie" :age 35 :city "Chocolate Factory"}]
+
+;; more columnar format:
+^:kind/table
+{:name ["Alice" "Bob" "Charlie"]
+ :age [30 25 35]
+ :city ["Wonderland" "Builderland" "Chocolate Factory"]}
+
+;; and display it as a portal widget:
+^:kind/portal
+{:name ["Alice" "Bob" "Charlie"]
+ :age [30 25 35]
+ :city ["Wonderland" "Builderland" "Chocolate Factory"]}