Tutorial: Retro Computer Screen Typewriter Effect

Expression 1 (Typewriter effect):

L = text.sourceText.length;
T = time*effect("Speed")("Slider");
F = Math.round(T % 1);

if(F==1 |(T <L & T>0)){Fl="_";}else{Fl=" ";}

substr(0,T) + Fl;
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Expression 2 (Position of bottom line stays in place):

pos = this.sourceRectAtTime(time).height;
value-[0,pos];