dbg_up/dbg_down

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

Dear PARI developers,

As discussed at the Ateliers PARI/GP,
I have implemented the dunction dbg_up/dbg_down for use in
the breaklook. This is mostly useful to see hidden variables:

This is an example session.

? f(i)=bnfinit(x^2-i).no;
? for(j=1,10,print(j,":",f(j^3+1)))
1:1
  ***   at top-level: for(j=1,10,print(j,":",f(j^3+1)))
  ***                                        ^----------
  ***   in function f: bnfinit(x^2-i).no
  ***                  ^-----------------
  *** bnfinit: not an irreducible polynomial in nfinit: x^2 - 9.
  ***   Break loop: type 'break' to go back to GP
break> i
9
break> j
j
break> dbg_up()
  ***   at top-level: for(j=1,10,print(j,":",f(j^3+1)))
  ***                                        ^----------
break> j
2

Cheers,
Bill.