how to reduce libsingular verbosity?

[Brent W. Baccala]

I'm trying to use some functions from Singular's "normal" library, which is pretty verbose, i.e:

sage: R.<x,y> = GF(3)[]
sage: S = R.quo(ideal(y^4 + y - x^5))
sage: from sage.libs.singular.function import singular_function
sage: normalC = sage.libs.singular.function_factory.ff.normal__lib.normalC
sage: normalC(S.defining_ideal(), ['withGens'])[1][0]


// 'normalC' created a list, say nor, of three lists:
// To see the list type
      nor;


// * nor[1] is a list of 1 ring(s)
// To access the i-th ring nor[1][i] give it a name, say Ri, and type e.g.
     def R1 = nor[1][1]; setring R1;  norid; normap;
// For the other rings type first (if R is the name of your original basering)
     setring R;
// and then continue as for R1.
// Ri/norid is the affine algebra of the normalization of the i-th
// component R/P_i (where P_i is an associated prime of the input ideal id)
// and normap the normalization map from R to Ri/norid.


// * nor[2] is a list of 1 ideal(s), each ideal nor[2][i] consists of
// elements g1..gk of R such that the gj/gk generate the integral
// closure of R/P_i as sub-algebra in the quotient field of R/P_i, with
// gj/gk being mapped by normap to the j-th variable of Ri;


// * nor[3] shows the delta-invariant of each component and of id
// (-1 means infinite, and 0 that R/P_i resp. R/id is normal).
[y^4 + y, x^4*y, x^3*y^3 - x^3*y^2 + x^3*y, x^2*y^3 - x^2*y^2 + x^2*y, x^3*y^2 + x^3*y, x*y^3 - x*y^2 + x*y, x^4]
sage:

I'd like to get rid of that long message and just see the result.

Is there any way to control Singular's "printlevel" variable from Sage?

[Brent W. Baccala]

This is what I figured out to adjust Singular's printlevel:

from sage.libs.singular import function_factory
execute = function_factory.ff.execute
execute('printlevel=-1')

Now that previous example runs without all the clutter:

sage: R.<x,y> = GF(3)[]

....: S = R.quo(ideal(y^4 + y - x^5))
....: from sage.libs.singular.function import singular_function
....: normalC = sage.libs.singular.function_factory.ff.normal__lib.normalC
....: normalC(S.defining_ideal(), ['withGens'])[1][0]
....:

[Brent W. Baccala]

Expanding on my previous answer, I found a way to save printlevel and restore it when I'm done.  The key idea is try to get a handle to a function that may not exist, then create it if it doesn't:

from sage.libs.singular.function import singular_function, lib
lib('normal.lib')
normal = singular_function('normal')
execute = singular_function('execute')

try:
    get_printlevel = singular_function('get_printlevel')
except NameError:
    execute('proc get_printlevel {return (printlevel);}')
    get_printlevel = singular_function('get_printlevel')

saved_printlevel = get_printlevel()
execute('printlevel=-1')
pols_in_S = normal(S.ideal(g))[1][0]
execute('printlevel={}'.format(saved_printlevel))