SILE.typesetter:typeset(SILE.toPoints("100%ph") .. " x " .. SILE.toPoints("100%pw"))

SILE.typesetter:typeset(("%.0f x %.0f"):format(SILE.toPoints("100%ph"), SILE.toPoints("100%pw")))

Fix output with lua 5.3
Fix output with lua 5.3