Entering the whileTrue: object at the st> prompt causes a parser error

[Gary Highberger]

ifTrue: works as expected, whileTrue: fails. Is this behavior known, expected?

st> (true) ifTrue: ['foobar']
'foobar'
st> (true) whileTrue: ['foobar']
Object: true error: did not understand #whileTrue:
MessageNotUnderstood(Exception)>>signal (ExcHandling.st:254)
True(Object)>>doesNotUnderstand: #whileTrue: (SysExcept.st:1448)
UndefinedObject>>executeStatements (a String:1)
nil
st>