//ketlib
pL=[];
hintflg=0;

//figures
Getvalue(no,default):=(
  regional(str,out,tmp);
  out=default;
  str=Textedit(no);
  tmp=indexof(str,"=");
  if(tmp>0,
    str=substring(str,tmp,length(str));
    if(length(str)>0,
      out=parse(str);
    );
  );
  out;
);

Ketinit();
Setketcindyjs(["Nolabel=all"]);
Setwindow([-5,5],[-5,5]);

ww=round(NE.x-SW.x);
hh=round(NE.y-SW.y);
xL0=apply(1..ww,10);
yL0=apply(1..hh,10);
Tabledata(xL0,yL0,[],[0,"dr,0.5","Move=SW.xy"]);
htick=[];
tmp=(round(SW.x))..(round(NE.x));
forall(remove(tmp,[0]),
  htick=concat(htick,[#,text(#)]);
);
Htickmark(htick,["Size=1.5"]);
vtick=[];
tmp=(round(SW.y))..(round(NE.y));
forall(remove(tmp,[0]),
 vtick=concat(vtick,[#,text(#)]);
);
Vtickmark(vtick,["Size=1.5"]);
Addax(1);

a=2;
x=""; y="";
//a=Getvalue(50,2); //only ketjs on
//x=Getvalue(51,"");
//y=Getvalue(52,""); //only ketjs off
opred=["Size=1.6","Color=red"];
opblue=["Size=1.6","Color=blue"];
opred3=["Size=3","Color=red"];
opblue3=["Size=3","Color=blue"];
loga(a,x):=log(x)/log(a);
Plotdata("1",Assign("a^x",["a",a]),"x",["Color=blue"]);
pos=[loga(a,NE.y),NE.y+0.7];
Expr(pos,"w","y="+a+"^x",opblue);
pos=[loga(a,NE.y),NE.y+0.7];
Expr(pos+[1,0],"e","y=\log_{"+a+"}"+"x",opred);
if((!isstring(x))&(!isstring(y)),
  Pointdata("1",[0,x],opblue3);
  tmp=[NE.x+1,0];
  Expr(tmp,"ne","y=\log_{"+a+"}"+x,["Size=1.6"]);
  if(hintflg==1,
    tmp=[[0,x],[loga(a,x),x],[loga(a,x),0]];
    Listplot("1",tmp,["dr,2","Color=red"]);
  );
  tmp=[NE.x+1,-2];
  if(|y-loga(a,x)|<0.1,
    tmp1="Correct! y="+Sprintf(loga(a,x),4);
    Letter(tmp,"e",tmp1,opred);
    pL=append(pL,[x,y]);
    Changestyle(["sg1"],["nodisp"]);
  ,
    Letter(tmp,"e","Not correct",opred);
  );
);
if(length(pL)>0,
  Pointdata("2",pL,opred3);
);

Windispg();