'added inport':
  from: |
    'default' -> IN read(ReadSomething)
  to: |
    INPORT=read.IN:FILENAME
    'default' -> IN read(ReadSomething)
  diff: "+ INPORT=read.IN:FILENAME"

'removed inport':
  from: |
    INPORT=read.IN:FILENAME
    'default' -> IN read(ReadSomething)
  to: |
    'default' -> IN read(ReadSomething)
  diff: "- INPORT=read.IN:FILENAME"

'renamed inport':
  from: |
    INPORT=read.IN:FILENAME
    'default' -> IN read(ReadSomething)
  to: |
    INPORT=read.IN:newfilename
    'default' -> IN read(ReadSomething)
  diff: ".rename INPORT=read.IN:newfilename was INPORT=read.IN:FILENAME"

'added outport':
  from: |
    INPORT=read.IN:FILENAME
    'default' -> IN read(ReadSomething)
  to: |
    INPORT=read.IN:FILENAME
    OUTPORT=read.OUT:OUTPUT
    'default' -> IN read(ReadSomething)
  diff: "+ OUTPORT=read.OUT:OUTPUT"

'removed outport':
  from: |
    INPORT=read.IN:FILENAME
    OUTPORT=read.OUT:OUTPUT
    OUTPORT=read.ERROR:ERROR
    'default' -> IN read(ReadSomething)
  to: |
    INPORT=read.IN:FILENAME
    OUTPORT=read.OUT:OUTPUT
    'default' -> IN read(ReadSomething)
  diff: "- OUTPORT=read.ERROR:ERROR"

'change target of outport':
  from: |
    INPORT=read.IN:FILENAME
    OUTPORT=read.OUT:OUTPUT
    'default' -> IN read(ReadSomething)
  to: |
    INPORT=read.IN:FILENAME
    OUTPORT=read.OUTPUT:OUTPUT
    'default' -> IN read(ReadSomething)
  diff: ". OUTPORT=read.OUTPUT:OUTPUT was OUTPORT=read.OUT:OUTPUT"