<para>
Hint: GHCi will tab-complete names that are in scope; for
example, if you run GHCi and type <literal>J<tab></literal>
<para>
Hint: GHCi will tab-complete names that are in scope; for
example, if you run GHCi and type <literal>J<tab></literal>
instance that returns <literal>IO a</literal>.
However, it is only able to return
<literal>undefined</literal>
instance that returns <literal>IO a</literal>.
However, it is only able to return
<literal>undefined</literal>
- (the reason for the instance having this type is to not require
- extensions to the class system), so if the type defaults to
+ (the reason for the instance having this type is so that printf
+ doesn't require extensions to the class system), so if the type defaults to
function definition or expression in the program. When the function
is called, or the expression evaluated, GHCi suspends
execution and returns to the prompt, where you can inspect the
function definition or expression in the program. When the function
is called, or the expression evaluated, GHCi suspends
execution and returns to the prompt, where you can inspect the
<title>Listing and deleting breakpoints</title>
<para>The list of breakpoints currently enabled can be displayed using
<title>Listing and deleting breakpoints</title>
<para>The list of breakpoints currently enabled can be displayed using
<para>Most of the command-line options accepted by GHC (see <xref
linkend="using-ghc"/>) also make sense in interactive mode. The ones
<para>Most of the command-line options accepted by GHC (see <xref
linkend="using-ghc"/>) also make sense in interactive mode. The ones
- that don't make sense are mostly obvious; for example, GHCi
- doesn't generate interface files, so options related to interface
- file generation won't have any effect.</para>
+ that don't make sense are mostly obvious.</para>