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diff --git a/Com/Simatime/Core.scm b/Com/Simatime/Core.scm
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+(define-module (Com Simatime Core)
+  #:use-module ((ice-9 format))
+  #:export (
+            ;; simple printing
+            fmt printf pr prn
+
+                ;; navigating data
+            first next second rest
+
+            ;; booleans
+            true? false? nil nil?
+
+            ;; dev helpers
+            comment
+            ))
+
+(define (flip f)           (lambda (x y) (f y x)))
+(define (curry f a)        (lambda (b) (apply f (cons a (list b)))))
+(define pos?
+  (curry < 0))
+
+(define neg?
+  (curry > 0))
+
+(define (foldr f end lst)
+  (if (null? lst)
+    end
+    (f (car lst) (foldr f end (cdr lst)))))
+
+(define (foldl f acc lst)
+  (if (null? lst)
+    acc
+    (foldl f (f acc (car lst)) (cdr lst))))
+
+(define fold foldl)
+
+(define (unfold f init pred)
+  (if (pred init)
+    (cons init '())
+    (cons init (unfold f (f init) pred))))
+
+(define (sum lst)          (fold + 0 lst))
+(define (produce lst)      (fold * 1 lst))
+
+(define count length)
+
+
+;;
+;; clojure-like stuff
+;;
+
+(define (pr . a)
+  (for-each display a))
+
+(define (prn . a) (apply pr a) (newline))
+
+(define (first a)
+  "Return the first item in the collection."
+  (car a))
+
+(define (rest a)
+  "Returns a list of the items after the first."
+  (cdr a))
+
+(define (next a)
+  "Returns the next item after the first."
+  (cadr a))
+
+;; same thing, easier to remember/read
+(define second next)
+
+(define (ffirst a)
+  (first (first a)))
+
+(define (nnext a)
+  (next (next a)))
+
+(define (last coll)
+  "Return the last time in coll, in linear time."
+  (if (next coll)
+      (last coll)
+      (first coll)))
+
+(define (butlast ls)
+  "Return everthing execpt the last element in ls."
+  (let ((len (length ls)))
+    (list-head ls (- len 1))))
+
+(define (false? x)
+  (eq? #f x))
+
+(define (true? x)
+  (eq? #t x))
+
+(define nil #nil)
+
+(define (nil? x)
+  (eq? nil x))
+
+;; Ignores body, returns nil.
+(define-syntax comment
+  (syntax-rules ()
+    ((_ ...) nil)))
+
+(comment
+ ;; nil is different from null. nil is supposed to be more like
+ ;; 'Nothing' in Haskell, it is the absence of any value or type;
+ ;; whereas null is specifically the empty list, which still has a type
+ ;; of 'list'.
+ (null? '()) ;; => #t
+ (nil? '())  ;; => #f
+ )
+
+(define (some pred coll)
+  (or (pred (first coll))
+      (some pred (next coll))))
+
+(define comp compose)
+
+(define (not-any? pred coll)
+  (comp not some))
+
+(define (printf . args)
+  (display (apply format args)))
+
+(define-syntax fmt
+  (syntax-rules ()
+    ((_ s args ...)
+     (format #f s args ...))))
+
+;; If I implement ML-like interface abstractions in scheme, what would it look like?
+
+;; 
+;; ;; seq
+
+;; (define-class <seq> () (_first))
+
+;; 
+;; ;; Functor
+
+;; (define-class <functor> ())
+
+;; (define-method (fmap (f <procedure>) (coll <functor>)))
+
+;; 
+;; ;; Applicative
+
+;; ;; a -> f a
+;; (define-method (pure (a <any>)))
+
+;; ;; f (a -> b) -> f a -> f b
+;; (define-method (<*> (f <procedure>) (a <applicative>) (b <applicative>)))
+
+;; ;; f a -> f b -> f b
+;; (define-method (*> (a <applicative>) (b <applicative>)))
+
+;; ;; f a -> f b -> f a
+;; (define-method (<* (a <applicative>) (b <applicative>)))