X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=docs%2Fusers_guide%2Fghci.xml;h=929e9dd37686c87d65e4e4c38809978e9507c994;hp=b5642b127fff061260371412e715055a32050884;hb=0583778f773db20f20c547aa67abe59dfc77b875;hpb=e8982ebc45244da2f414eb920dfa798dbdc8cebc diff --git a/docs/users_guide/ghci.xml b/docs/users_guide/ghci.xml index b5642b1..929e9dd 100644 --- a/docs/users_guide/ghci.xml +++ b/docs/users_guide/ghci.xml @@ -633,9 +633,9 @@ Prelude> it * 2 expression, and if it doesn't have an IO type, then it transforms it as follows: an expression e turns into - - let it = e; - print it + +let it = e; +print it which is then run as an IO-action. @@ -644,10 +644,14 @@ Prelude> it * 2 complain: -Prelude> id -No instance for `Show (a -> a)' -arising from use of `print' -in a `do' expression pattern binding: print it +Prelude> id + +<interactive>:1:0: + No instance for (Show (a -> a)) + arising from use of `print' at <interactive>:1:0-1 + Possible fix: add an instance declaration for (Show (a -> a)) + In the expression: print it + In a 'do' expression: print it The error message contains some clues as to the @@ -659,14 +663,15 @@ in a `do' expression pattern binding: print it which is of type a. eg.: Prelude> Time.getClockTime +Wed Mar 14 12:23:13 GMT 2001 Prelude> print it Wed Mar 14 12:23:13 GMT 2001 The corresponding translation for an IO-typed e is - - it <- e + +it <- e