On Fri, Jan 13, 2017 at 09:51:51AM +0100, Otto Moerbeek wrote:
> On Fri, Jan 13, 2017 at 09:46:54AM +0100, Anton Lindqvist wrote:
>
> > Consider the following script which calculates the sum of the first N
> > integers recursively:
> >
> > $ cat >sum.sh <<!
> > sum() {
> > [ $1 -eq 0 ] && echo $2 || sum $(($1 - 1)) $(($2 + $1))
> > }
> >
> > sum 5
> > !
> >
> > Executing the script with the x option gives the following output:
> >
> > $ sh -x sum.sh
> > + sum 5
> > 15
> >
> > I would expect the recursive calls to be traced, similar to how GNU
> > bash/sh behaves. With the patch below applied the output is as expected:
> >
> > $ sh -x sum.sh
> > + sum 5
> > + [ 5 -eq 0 ]
> > + sum 4 5
> > + [ 4 -eq 0 ]
> > + sum 3 9
> > + [ 3 -eq 0 ]
> > + sum 2 12
> > + [ 2 -eq 0 ]
> > + sum 1 14
> > + [ 1 -eq 0 ]
> > + sum 0 15
> > + [ 0 -eq 0 ]
> > + echo 15
> > 15
> >
> > The patch make sure to assigns the TRACE flag to every user-defined
> > function if the x option is present. The piece of code that led me to
> > this:
> >
> > $ sed -n 606,607p /usr/src/bin/ksh/exec.c
> > old_xflag = Flag(FXTRACE);
> > Flag(FXTRACE) = tp->flag & TRACE ? true : false;
>
> Hmmm,
>
> afaik -x has always been local to a function in ksh-like shells.
> To enable tracing within function call set -x in the fucntion te be traced.
or set the trace attribute for a specific function:
typeset -ft sum
>
> -Otto
>
> >
> > Index: exec.c
> > ===================================================================
> > RCS file: /cvs/src/bin/ksh/exec.c,v
> > retrieving revision 1.68
> > diff -u -p -r1.68 exec.c
> > --- exec.c 11 Dec 2016 17:49:19 -0000 1.68
> > +++ exec.c 12 Jan 2017 20:10:48 -0000
> > @@ -796,6 +796,9 @@ define(const char *name, struct op *t)
> > if (t->u.ksh_func)
> > tp->flag |= FKSH;
> >
> > + if (Flag(FXTRACE))
> > + tp->flag |= TRACE;
> > +
> > return 0;
> > }
