<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I'm trying to find some way of minimally marking up a text that contains a lot of fractions. I thought that \XeTeXinterchartoks might come to the rescue. Something like:<div><br></div><div>%%=====%%</div><div><br></div><div><div>% !TEX encoding = UTF-8 Unicode</div><div>% !TEX TS-program = xetex</div><div><br></div><div>\XeTeXinterchartokenstate = 1 </div><div><br></div><div>\XeTeXcharclass `\1 7 </div><div>\XeTeXcharclass `\2 7</div><div>\XeTeXcharclass `\3 7</div><div><br></div><div>\def\makefrac#1/#2{#1yy#2}</div><div><br></div><div>\XeTeXinterchartoks 255 7 = {\makefrac}</div><div><br></div><div>test 1/2 more</div><div><br></div><div>\bye</div><div><br></div><div>%%=====%%</div><div><br></div><div>This is plain TeX sample for simplicity's sake, and the definition of \makefrac will be changed to make the appropriate font call.</div><div><br></div><div>The problem arises, as has been discussed before, that the frac OT feature turns on the feature for all numbers, not just those surrounding a slash. As all of the fractions are preceded by spaces, I thought that the above might work. It does not. It gives this fairly unexpected (to me, that is) error:</div><div><br></div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; ">! Paragraph ended before \makefrac was complete.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; "><to be read again> </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; "> \par </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; ">l.15 </div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; ">What am I doing wrong?</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; ">Thanks.</div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 10px/normal Monaco; ">Stephen Moye</div></div></div></body></html>