Put yaml parsing into its own namespace

Future content parsers will need to use the same yaml parsing that
`markdown` does. This is a modified form of changes in hashobject#113.

Author: bhagany

src/io/perun/markdown.clj

@@ -1,12 +1,8 @@
 (ns io.perun.markdown
   (:require [io.perun.core   :as perun]
-            [clojure.java.io :as io]
-            [clojure.string  :as str]
-            [clj-yaml.core   :as yaml]
-            [clojure.walk    :as walk])
-  (:import [org.pegdown PegDownProcessor Extensions]
-           [flatland.ordered.map OrderedMap]
-           [flatland.ordered.set OrderedSet]))
+            [io.perun.yaml   :as yaml]
+            [clojure.java.io :as io])
+  (:import [org.pegdown PegDownProcessor Extensions]))
 
 ;; Extension handling has been copied from endophile.core
 ;; See https://github.com/sirthias/pegdown/blob/master/src/main/java/org/pegdown/Extensions.java
@@ -35,8 +31,6 @@
    :all-optionals        Extensions/ALL_OPTIONALS
    :all-with-optionals   Extensions/ALL_WITH_OPTIONALS})
 
-(def ^:dynamic *yaml-head* #"---\r?\n")
-
 (defn extensions-map->int [opts]
   (->> opts
        (merge {:autolinks true
@@ -49,55 +43,17 @@
        (apply bit-or 0)
        int))
 
-(defn substr-between
-  "Find string that is nested in between two strings. Return first match.
-  Copied from https://github.com/funcool/cuerdas"
-  [s prefix suffix]
-  (cond
-    (nil? s) nil
-    (nil? prefix) nil
-    (nil? suffix) nil
-    :else
-    (some-> s
-            (str/split prefix)
-            second
-            (str/split suffix)
-            first)))
-
-(defn normal-colls
-  "Clj-yaml keeps order of map properties by using ordered maps. These are inconvenient
-  for us as the ordered library is not necessarily available in other pods."
-  [x]
-  (walk/postwalk
-    (fn [y]
-      (cond
-        (instance? OrderedMap y) (into {} y)
-        (instance? OrderedSet y) (into #{} y)
-        :else y))
-    x))
-
-(defn parse-file-metadata [file-content]
-  (when-let [metadata-str (substr-between file-content *yaml-head* *yaml-head*)]
-    (when-let [parsed-yaml (normal-colls (yaml/parse-string metadata-str))]
-      parsed-yaml)))
-
-(defn remove-metadata [content]
-  (let [splitted (str/split content *yaml-head* 3)]
-    (if (> (count splitted) 2)
-      (first (drop 2 splitted))
-      content)))
-
 (defn markdown-to-html [file-content options]
   (let [processor (PegDownProcessor. (extensions-map->int (:extensions options)))]
     (->> file-content
-         remove-metadata
+         yaml/remove-metadata
          char-array
          (.markdownToHtml processor))))
 
 (defn process-file [file options]
   (perun/report-debug "markdown" "processing markdown" (:filename file))
   (let [file-content (-> file :full-path io/file slurp)
-        md-metadata (merge (:meta options) (parse-file-metadata file-content))
+        md-metadata (merge (:meta options) (yaml/parse-file-metadata file-content))
         html (markdown-to-html file-content (:options options))]
     (merge md-metadata {:content html} file)))
 

src/io/perun/yaml.clj

@@ -0,0 +1,45 @@
+(ns io.perun.yaml
+  (:require [clojure.string  :as str]
+            [clj-yaml.core   :as yaml]
+            [clojure.walk    :as walk])
+  (:import [flatland.ordered.map OrderedMap]
+           [flatland.ordered.set OrderedSet]))
+
+(def ^:dynamic *yaml-head* #"---\r?\n")
+
+(defn substr-between
+  "Find string that is nested in between two strings. Return first match.
+  Copied from https://github.com/funcool/cuerdas"
+  [s prefix suffix]
+  (cond
+    (nil? s) nil
+    (nil? prefix) nil
+    (nil? suffix) nil
+    :else
+    (some-> s
+            (str/split prefix)
+            second
+            (str/split suffix)
+            first)))
+
+(defn normal-colls
+  "Clj-yaml keeps order of map properties by using ordered maps. These are inconvenient
+  for us as the ordered library is not necessarily available in other pods."
+  [x]
+  (walk/postwalk
+    (fn [y]
+      (cond
+        (instance? OrderedMap y) (into {} y)
+        (instance? OrderedSet y) (into #{} y)
+        :else y))
+    x))
+
+(defn parse-file-metadata [file-content]
+  (when-let [metadata-str (substr-between file-content *yaml-head* *yaml-head*)]
+    (normal-colls (yaml/parse-string metadata-str))))
+
+(defn remove-metadata [content]
+  (let [splitted (str/split content *yaml-head* 3)]
+    (if (> (count splitted) 2)
+      (first (drop 2 splitted))
+      content)))