Jean Abou Samra schreef op di 19-04-2022 om 18:52 [+0200]: > The simple file > > (format #f "~f" 'invalid) > > gives me > > FORMAT: error with call: (format #f "~f<===" ===>invalid ) >          argument is not a number or a number string > FORMAT: INTERNAL ERROR IN FORMAT-ERROR! >          destination: #f >          format string: "~f" >          format args: (invalid) >          error args:  (#f "error in format" () #f) > ice-9/boot-9.scm:1685:16: In procedure raise-exception: > error in format > > > Is it expected to see 'INTERNAL ERROR IN FORMAT-ERROR!'? > To me, that has a meaning similar to an assertion failure. Doesn't look internal to me, looks like an error at the use site of 'format'. I think the error message can be reworded a bit to make it clearer: format: The format string is incompatible with the passed arguments. relevant part of format string: "~f" invalid argument: invalid expected: a number destination: #f format string: "~f" format arguments: (invalid) [no error args, because that would be redundant] Greetings, Maxime.