initial commit

.gitignore

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+pom.xml
+*jar
+lib
+classes

README.md

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+# pretzel
+
+General predicate functions.
+Combine predicates into new ones, plus a bunch of predicates on strings.
+
+## Usage
+
+   (looks-like-email? "foo@example.com")
+   (natural? "1234")
+   (integer? "-123213")
+   (web-url "http://foo.bar/somewhere")
+   (hex? "deadb33f")
+   (length? "bla" 3)
+   (length? "bla" 2 4)
+
+   ((every-p?
+     natural
+     #(length % 2 3)
+    "123")
+
+## License
+
+Copyright (C) 2010 Joost Diepenmaat, Zeekat Softwareontwikkeling
+joost@zeekat.nl - http://joost.zeekat.nl/
+
+Distributed under the Eclipse Public License, the same as Clojure.

project.clj

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+(defproject pretzel "1.0.0-SNAPSHOT"
+  :description "FIXME: write"
+  :dependencies [[org.clojure/clojure "1.2.0"]
+                 [org.clojure/clojure-contrib "1.2.0"]])

src/pretzel/combine.clj

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+(ns pretzel.combine
+  {:doc "Combine predicates"})
+
+(defn combine-p
+  "Combine predicates using collection function f.
+Returns a new predicate that tests the collection of predicates
+against the given value(s) using f."
+  [f predicates]
+  (fn [& values]
+    (f #(apply % values) predicates)))
+
+(defn every-p?
+  "Create a new predicate which is true if every predicate is true"
+  [& predicates]
+  (combine-p every? predicates))
+
+(defn some-p
+  "Create a new predicate returning the first true value of predicates"
+  [& predicates]
+  (combine-p some predicates))
+
+(defn not-any-p?
+  "Create a new predicate returning false if all predicates return true"
+  [& predicates]
+  (combine-p not-any? predicates))
+
+(defn not-every-p?
+  "Create a new predicate returning true if any predicate returns false"
+  [& predicates]
+  (combine-p not-every? predicates))
+
+

src/pretzel/strings.clj

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+(ns pretzel.strings
+  {:doc "Predicates on strings"}
+  (:import java.net.URL
+           java.net.MalformedURLException))
+
+(defn length?
+  "true if length of string s is len or within the range [min ... max]"
+  ([^String s len]
+     (= (.length s) len))
+  ([^String s min max]
+     (<= min (.length s) max)))
+
+(defn natural?
+  "s represents a natural number (0 - 9999...)"
+  [^String s]
+  (re-matches #"\A[0-9]+\z"))
+
+(defn integer?
+  "s represents an integer (- 999... to 999...)"
+  [^String s]
+  (re-matches #"\A-?[0-9]+\z"))
+
+(defn hex?
+  "s is a hexadecimal string (case-insensitive)"
+  [^String s]
+  (re-matches #"\A[0-9A-Fa-f]+\z" s))
+
+(defn blank?
+  "s contains only whitespace"
+  [^String s]
+  (every? #(Character/isWhitespace %) s))
+
+(defn url
+  "return a java.net.URL from string or nil if s is malformed.
+Note that this will mean any URL valid according to java.net.URL"
+  [^String s]
+  (try
+    (URL. s)
+    (catch MalformedURLException e
+      nil)))
+
+(defn web-url
+  "returns a java.net.URL if that is an http or https URL"
+  [^String s]
+  (if-let [u (url s)]
+    (if-let [p (.getProtocol s)]
+      (or (= p "http")
+          (= p "https")))))
+
+(defn looks-like-email?
+  "a fairly permissive check; s should contain no whitespace, a @
+  character between the name and the domain, and a dot in the domain.
+People with email at a TLD probably have other mail addresses too"
+  [^String s]
+  (re-matches #"\A[^\s@]+@[^\s@]+\.[^\s@]+\z" s))