add get_input facility to environment

TODO.org

@@ -36,7 +36,7 @@ I see at least before three projects to complete before making the first release
       result. I think this is not an issue (Maude)
     - [ ] Its calling signature should be rethought
     - The name should be changed in glob_parents and glob_seg
-  - [ ] Are we satisfied with seg_input, is this convenient, should we
+  - [X] Are we satisfied with seg_input, is this convenient, should we
     provide extra function to ease the retrieval of inputs.
   - [ ] Are we satisfied with the lst_par, lst_tag, load_param syntax (may become save(name1,name2 ...) and expose(name1,name2...))
   - [ ] logged_subprocess is the function I use in every segment,

pipelet/environment.py

@@ -151,6 +151,33 @@ class Environment(EnvironmentBase):
         self.logger = init_logger (self._get_data_fn(""), self._get_log_file(), level=[])
 
 
+    def get_input(self, seg=None):
+        """ Get segment input.
+        
+        Parameters
+        ----------
+        seg: string segment name
+        
+        Returns
+        -------
+        python object or None
+        """
+        if isinstance(self.seg_input, dict):
+            if seg is not None:
+                if self.seg_input.has_key(seg):
+                    return self.seg_input[seg]
+                else:
+                    self.logger.info("No input from parent named %s", seg)
+            else:
+                if len(self.seg_input.values())>0:
+                    return self.seg_input.values()[0]
+                else:
+                    self.logger.info("Empty input list")
+        elif isinstance(self.seg_input, list) and  len(self.seg_input)==0:
+            self.logger.info("Empty input list")
+        else:
+            return self.seg_input
+        return None
 
     def get_data_fn(self, x):
         """ Complete the filename with the path to the working

test/multiplex/a.py

 print seg_input
 import os
-os.system("touch %s"%get_data_fn("file%d.dat"%seg_input.values()[0]))
-seg_output = [seg_input.values()[0]]
+inp = get_input()
+os.system("touch %s"%get_data_fn("file%d.dat"%inp))
+seg_output = [inp]

test/multiplex/b.py

 #seg_output = ['aa', 'bb']
 import os
 print seg_input
-os.system("touch %s"%get_data_fn("bbbb%d.dat"%seg_input.values()[0]))
-#seg_output = [(seg_input.values()[0], "pp")]
+inp = get_input()
+os.system("touch %s"%get_data_fn("bbbb%d.dat"%inp))
+seg_output = [(inp, "pp")]

test/multiplex/c.py

 #multiplex cross_prod group_by "0"
+
 print seg_input
+
 import os
 f = glob_seg("a", "file*.dat")
 for file in f: