On Wed, Apr 5, 2017 at 10:15 AM, Ulrike Fischer
\starttext
\font\test={file:linlibertine_r.otf:+frac} \test 1/2 3/4 5/6 7/8 9/10 11/12 31415/27182 1000/1000000 \stoptext
gives as output
½ 3¾ 5⅚ 7⅜ 9/10 1⅟12 31415/27182 1000/1000000
\usetypescriptfile[libertine] \setupbodyfont[libertine,12pt] \definefontfeature[frac][frac=yes] \starttext {\addff{frac} 1/2 3/4 5/6 7/8 9/10 11/12 31415/27182 1000/1000000} \stoptext if you see fonts > otf chain > feature 'frac', type 'gsub_contextchain', chain lookup 's_s_7': is not yet supported (1) then ... it need to be supported. ( I have a local patch (by Hnas) that gives ¹⁄₂ ³⁄₄ ⁵⁄₆ ⁷⁄₈ ⁹⁄₁₀ ¹¹⁄₁₂ ³¹⁴¹⁵⁄₂₇₁₈₂ ¹⁰⁰⁰⁄₁₀₀₀₀₀₀ with the otf fonts from http://www.ctan.org/tex-archive/fonts/libertine ) -- luigi