allow support module name in info() tag

Gives the option of reducing the input link
length and preventing runtime switching of
module.

devsupApp/src/devsup/db.py

@@ -320,11 +320,19 @@ def processLink(name, lstr):
     """Process the INP or OUT link
     
     Expects lstr to be "module arg1 arg2"
+    if the 'pySupportMod' info tag is not given.
+    When it is, the link string is passed
+    to the module build() function without
+    processing.
 
-    Returns (callable, Record, "arg1 arg2")
+    Returns (Record, Support)
     """
     rec = getRecord(name)
+    modname = rec.info('pySupportMod', None)
+    if not modname:
         parts = lstr.split(None,1)
         modname, args = parts[0], parts[1] if len(parts)>1 else None
+    else:
+        args = lstr
     mod = importmod(modname)
     return rec, mod.build(rec, args)

documentation/interfaces.rst

@@ -150,13 +150,22 @@ This support code can then be referenced from records. ::
 
   record(longin, "my:int:counter") {
     field(DTYP, "Python Device")
-    field(INP , "counter hello world")
+    field(INP , "@counter hello world")
   }
   
 The following will fail to associate. ::
 
   record(longin, "my:int:counter") {
     field(DTYP, "Python Device")
-    field(INP , "counter do what I say")
+    field(INP , "@counter do what I say")
   }
 
+If a shorter INP link string is necessary, or to prevent
+runtime switching of modules, the module name may also
+be given in the *pySupportMod* info() tag. ::
+
+  record(longin, "my:int:counter") {
+    field(DTYP, "Python Device")
+    field(INP , "@hello world")
+    info("pySupportMod", "counter")
+  }