Implemented 'generate only these targets'

TODO.md

@@ -2,5 +2,4 @@ Thinks it may make sense to add:
 
 * Tasks without file output
 * Tasks with more than one output
-* Run only tasks needed to produce specific outputs
-* Run only listed tasks
+* ~~Run only tasks needed to produce specific outputs~~

spec/croupier_spec.cr

@@ -382,6 +382,19 @@ describe Croupier::Task do
     end
   end
 
+  it "should run only required tasks to produce specified outputs" do
+    with_tasks do
+      Dir.cd "spec/files" do
+        Croupier::Task.run_tasks(["output4", "output5"])
+        File.exists?("output1").should be_false
+        File.exists?("output2").should be_false
+        File.exists?("output3").should be_true # Required for output4
+        File.exists?("output4").should be_true # Required
+        File.exists?("output5").should be_true # Required
+      end
+    end
+  end
+
   it "should fail if asked for dependencies of an unknown output" do
     with_tasks do
       Dir.cd "spec/files" do

src/croupier.cr

@@ -160,7 +160,7 @@ module Croupier
     end
 
     # Run the tasks needed to create or update the requested targets
-    def self.run_tasks(targets : Array(String))
+    def self.run_tasks(targets : Array(String), run_all : Bool = false)
       mark_stale_inputs
       tasks = dependencies(targets)
       _run_tasks(tasks, run_all)
@@ -174,7 +174,7 @@ module Croupier
       _, tasks = Task.sorted_task_graph
       _run_tasks(tasks, run_all)
     end
-    
+
     # Helper to run tasks
     def self._run_tasks(tasks, run_all : Bool = false)
       tasks.each do |task|