Added "print" command to print a templates value to stdout

README.md

@@ -14,7 +14,7 @@ that is passed to stencil contains a combination of:
 
 To use from Leiningen add to `project.clj`:
 ```clojure
-:plugins [ [lein-resource "15.10.1"] ] 
+:plugins [ [lein-resource "15.10.2"] ] 
 ```
 To have it run before the jar file creation:
 ```clojure
@@ -60,6 +60,13 @@ To see all the properties that are passed to stencil:
 
     lein resource pprint
 
+
+To print the value of a stencil passed as an argument (useful for build scripts & testing templates)
+
+     lein resource print  "{{version}}"
+     export MY_PROJECT_VERSION=$(lein resource print "{{name}}:{{version}}")
+
+
 To delete all the copied files and empty directories:
 
     lein resource clean

project.clj

@@ -1,5 +1,5 @@
 
-(defproject lein-resource "15.10.1" 
+(defproject lein-resource "15.10.2" 
   :description 
   "
 A task that copies the files for the resource-paths to the
@@ -21,6 +21,12 @@ Remove the files created by the plugin.
      lein resource clean 
 
 
+###  Print
+Print the value of a stencil specified as an argument, useful for build scripts
+
+     lein resource print  \"{{version}}\"
+     export MY_PROJECT_VERSION=$(lein resource print \"{{name}}:{{version}}\")
+
 ### Pretty Print
 Dump the map of values sent to stencil.
 

src/leiningen/resource.clj

@@ -217,15 +217,19 @@ Return a FileSpec"
                         (verbose-msg project-info "file-spec-seq")
                         (map (partial copy-file-spec project-info)))))
 
+(defn print-task [value-map patterns]
+  (doseq [patt patterns]
+    (println (stencil/render-string patt value-map))))
+
 ;; ## resource
-;; This is the main entry point into the plugin.  It supports 3 tasks:
-;; copy, clean and pprint.
+;; This is the main entry point into the plugin.  It supports 4 tasks:
+;; copy, clean, print and pprint.
 ;;
 ;; This function creates the `ProjectInfo`, determines which task is
 ;; needs and calls it.
 
 (defn resource
-  "Task name can also be pprint or clean"
+  "Task name can also be print, pprint or clean"
   [project & task-keys]
   (stencil.loader/set-cache {})
   (let [{:keys [resource-paths target-path extra-values excludes includes 
@@ -245,11 +249,12 @@ Return a FileSpec"
           project-info (ProjectInfo. resource-paths target-path value-map includes excludes skip-stencil update silent verbose)]
       (verbose-msg project-info "project-info" project-info)
       ;;(println "TASK:" task-name)
-      (cond
-       (= "pprint" task-name) (pprint value-map)
-       (= "clean" task-name) (clean-task project-info)
-       (= "copy" task-name) (copy-task project-info)
-       :else (copy-task project-info)))))
+      (condp = task-name
+       "print" (print-task value-map (rest task-keys))
+       "pprint" (pprint value-map)
+       "clean" (clean-task project-info)
+       "copy" (copy-task project-info)
+       (copy-task project-info)))))
 
 (defn compile-hook [task & [project & more-args :as args]]
   (msg (:silent project) "Copying resources...")

test/plugin/test/core.clj

@@ -29,3 +29,9 @@
 (deftest test-pprint
   (let [^String r (with-out-str (resource project "pprint"))]
     (is (.contains r (str mykey)))))
+
+(deftest test-print
+  (let [out-str (with-out-str (resource project "print" "{{resource.target-path}}={{resource.extra-values.key}}"))
+        expected (str (get-in project [:resource :target-path]) "="
+                      (get-in project [:resource :extra-values mykey]) "\n")]
+    (is (= expected out-str))))