Alasdair McAndrew? points out that calls to iprint results in a hard error. He writes:

I was running a long program recently, and every now and again I wanted a little output to indicate how far the program had got. The "output" command includes a line feed, which I don't want. I've tried:

 )set expose add constructor IPRNTPK

but then, for example:

 for i in 1..10 repeat iprint(i::String)

produces the output:

 1
    >> System error:
    FLUSH is invalid as a function.

Although not exactly reproducable on Silver, there is an error and the fix appears to be:

 --- a/src/algebra/newdata.spad.pamphlet
 +++ b/src/algebra/newdata.spad.pamphlet
 @@ -49,7 +49,7 @@ InternalPrintPackage(): Exports == Implementation where
    Implementation == add
       iprint(s:String) == 
            PRINC(coerce(s)@Symbol)$Lisp
 -          FORCE_-OUTPUT$Lisp
 +          FORCE_-OUTPUT()$Lisp

Status: testing => pending (next release)

Status: pending (next release) => closed