medm: better macro handling

should fix:

https://bugzilla.ligo-wa.caltech.edu/bugzilla3/show_bug.cgi?id=1115

lib/guardian/medm/__main__.py

@@ -70,7 +70,6 @@ def main():
     """Exec Guardian MEDM screen for system.
 
     """
-
     args = parser.parse_args()
 
     if args.paths:
@@ -147,11 +146,12 @@ composite {{
     ############################################################
 
     cmd += ['-macro',
-            'IFO={ifo},SYSTEM={name},SYSTEM_PATH={path}'.format(
-                ifo=os.getenv('IFO'),
-                name=system.name,
-                path=system.path,
-                )]
+            gen.gen_macro_str(
+                IFO=const.IFO,
+                SYSTEM=system.name,
+                SYSTEM_PATH=system.path,
+            )
+    ]
 
     prefix = const.CAS_PREFIX_FMT.format(IFO=const.IFO, SYSTEM=system.name).strip('_')
     wargs = ()

lib/guardian/medm/gen.py

@@ -7,15 +7,23 @@ from .screens import get_path
 
 ##################################################
 
+MACROS = dict(
+    IFO = '$(IFO)',
+    SYSTEM = '$(SYSTEM)',
+    SYSTEM_PATH = '$(SYSTEM_PATH)',
+    )
+
+
+def gen_macro_str(**kwargs):
+    macros = MACROS.copy()
+    if kwargs:
+        macros.update(kwargs)
+    return ','.join(['{}={}'.format(k, v) for k, v in macros.items()])
+
+
 def gen_composite(**kwargs):
     path = get_path(kwargs['screen'])
-    macros = ['IFO=$(IFO)',
-              'SYSTEM=$(SYSTEM)',
-              ]
-    if 'macros' in kwargs:
-        macros += kwargs['macros']
-        del kwargs['macros']
-    macros = ','.join(macros)
+    kwargs['macros'] = gen_macro_str(**kwargs.get('macros', {}))
     return '''
 composite {{
         object {{
@@ -27,7 +35,7 @@ composite {{
         "composite name"=""
         "composite file"="{path}; {macros}"
 }}
-'''.format(path=path, macros=macros, **kwargs)
+'''.format(path=path, **kwargs)
 
 ##################################################
 
@@ -110,7 +118,8 @@ def write_screen_states(f, system):
                                                is_request=is_request,
                                                is_goto=is_goto,
                                                ))
-        f.write(gen_composite(screen='GRD_STATES_TARGET.adl', macros=['STATE_N={}'.format(index)],
+        f.write(gen_composite(screen='GRD_STATES_TARGET.adl',
+                              macros={'STATE_N': index},
                               x=x+270, y=y,
                               width=25, height=25))