  The pion light-cone distribution amplitude (LCDA) is a central
non-perturbative object of interest for high-energy exclusive processes in
quantum chromodynamics. In this article, the second Mellin moment of the pion
LCDA is determined as a proof-of-concept calculation for the first numerical
implementation of the heavy-quark operator product expansion (HOPE) method. The
resulting value for the second Mellin moment, determined in quenched QCD at a
pion mass of $m_\pi=550$ MeV at a factorization scale of 2 GeV is $ \langle
\xi^2 \rangle = 0.210 \pm 0.013\text{ (stat.)} \pm 0.034\text{ (sys.)}$. This
result is compatible with those from previous determinations of this quantity.
