Add float built-in parsers

src/crustimoney/built_ins.clj

@@ -44,20 +44,25 @@
   (c/with-error :expected-natural-number
     (c/regex #"\d+")))
 
+(def float
+  "Parse a floating point number."
+  (c/with-error :expected-float
+    (c/regex #"-?\d+(\.\d+)?")))
+
 (def word
   "Parse an alphabetical word."
   (c/with-error :expected-word
     (c/regex #"[A-Za-z]+")))
 
 (def dquote
-  "Parse an double quoted string, allowing \\\" escapes."
+  "Parse an double quoted string, including \\\" escapes."
   (c/with-error :expected-double-qoute-string
     (c/chain (c/literal "\"")
              (c/regex #"(\\\"|[^\"])*")
              (c/literal "\""))))
 
 (def squote
-  "Parse an single quoted string, allowing \\' escapes."
+  "Parse an single quoted string, including \\' escapes."
   (c/with-error :expected-single-qoute-string
     (c/chain (c/literal "'")
              (c/regex #"(\\'|[^'])*")

test/crustimoney/built_ins_test.clj

@@ -44,6 +44,15 @@
   (is (= #{(r/->error :expected-natural-number 0)}
          (core/parse b/natural "-10"))))
 
+(deftest float-test
+  (is (= (r/->success 0 3) (core/parse b/float "123")))
+  (is (= (r/->success 0 3) (core/parse b/float "-23")))
+  (is (= (r/->success 0 1) (core/parse b/float "0")))
+  (is (= (r/->success 0 4) (core/parse b/float "1.23")))
+  (is (= (r/->success 0 5) (core/parse b/float "-12.3")))
+  (is (= #{(r/->error :expected-float 0)}
+         (core/parse b/float "nan"))))
+
 (deftest word-test
   (is (= (r/->success 0 3) (core/parse b/word "Foo")))
   (is (= #{(r/->error :expected-word 0)}