Using units in mathjax and asciimathml - mathjax

Question

We're using MathJax to render ASCIIMathML equations with units of measure. We have found a situation where MathJax is being too clever for our own good...
3.14 in
renders as...
3.14 ∈
where ∈ is the set membership symbol.
Any suggestions on turning that cleverness off? The doc has some options but none that seem to cover this use case.
These are student entered strings so we can't ask them to understand the nuances of MathJax.
Thanks!
Jim

Answer 1

How about 3.14 text{in} or 3.14 text{ in} if you want a space between the number and unit?
Since you trying to use AsciiMath for student input, one approach would be to limit the number of commands that are available. For example, you can modify the symbol list to remove the ones you don't want. One approach would be to simply replace the list with a new one that contains only the ones you want (this may be the easiest way). For example, you could put the following code in your page just before the script tag that loads MathJax.js itself.
<script type="text/x-mathjax-config">
MathJax.Hub.Register.StartupHook("AsciiMath Jax Config",function () {
var AM = MathJax.InputJax.AsciiMath.AM;
var CONST = AM.TOKEN.CONST,
UNARY = AM.TOKEN.UNARY,
BINARY = AM.TOKEN.BINARY,
INFIX = AM.TOKEN.INFIX,
TEXT = AM.TOKEN.TEXT,
DEFINITION = AM.TOKEN.DEFITION,
UNDEROVER = AM.TOKEN.UNDEROVER,
LEFTRIGHT = AM.TOKEN.LEFTRIGHT,
LEFTBRACKET = AM.TOKEN.LEFTBRACKET,
RIGHTBRACKET = AM.TOKEN.RIGHTBRACKET;
AM.symbols.splice(0,AM.symbols.length,
{input:"*", tag:"mo", output:"\u22C5", tex:"cdot", ttype:CONST},
{input:"-:", tag:"mo", output:"\u00F7", tex:"div", ttype:CONST},
{input:"divide", tag:"mo", output:"-:", tex:null, ttype:DEFINITION},
{input:"!=", tag:"mo", output:"\u2260", tex:"ne", ttype:CONST},
{input:"lt", tag:"mo", output:"<", tex:null, ttype:CONST},
{input:"<=", tag:"mo", output:"\u2264", tex:"le", ttype:CONST},
{input:"lt=", tag:"mo", output:"\u2264", tex:"leq", ttype:CONST},
{input:"gt", tag:"mo", output:">", tex:null, ttype:CONST},
{input:">=", tag:"mo", output:"\u2265", tex:"ge", ttype:CONST},
{input:"gt=", tag:"mo", output:"\u2265", tex:"geq", ttype:CONST},
//grouping brackets
{input:"(", tag:"mo", output:"(", tex:null, ttype:LEFTBRACKET},
{input:")", tag:"mo", output:")", tex:null, ttype:RIGHTBRACKET},
{input:"[", tag:"mo", output:"[", tex:null, ttype:LEFTBRACKET},
{input:"]", tag:"mo", output:"]", tex:null, ttype:RIGHTBRACKET},
{input:"{", tag:"mo", output:"{", tex:null, ttype:LEFTBRACKET},
{input:"}", tag:"mo", output:"}", tex:null, ttype:RIGHTBRACKET},
{input:"|", tag:"mo", output:"|", tex:null, ttype:LEFTRIGHT},
{input:"(:", tag:"mo", output:"\u2329", tex:"langle", ttype:LEFTBRACKET},
{input:":)", tag:"mo", output:"\u232A", tex:"rangle", ttype:RIGHTBRACKET},
{input:"<<", tag:"mo", output:"\u2329", tex:null, ttype:LEFTBRACKET},
{input:">>", tag:"mo", output:"\u232A", tex:null, ttype:RIGHTBRACKET},
{input:"{:", tag:"mo", output:"{:", tex:null, ttype:LEFTBRACKET, invisible:true},
{input:":}", tag:"mo", output:":}", tex:null, ttype:RIGHTBRACKET, invisible:true},
//miscellaneous symbols
{input:"+-", tag:"mo", output:"\u00B1", tex:"pm", ttype:CONST},
{input:"O/", tag:"mo", output:"\u2205", tex:"emptyset", ttype:CONST},
{input:"oo", tag:"mo", output:"\u221E", tex:"infty", ttype:CONST},
{input:"...", tag:"mo", output:"...", tex:"ldots", ttype:CONST},
{input:"'", tag:"mo", output:"\u2032", tex:"prime", ttype:CONST},
{input:"CC", tag:"mo", output:"\u2102", tex:null, ttype:CONST},
{input:"NN", tag:"mo", output:"\u2115", tex:null, ttype:CONST},
{input:"QQ", tag:"mo", output:"\u211A", tex:null, ttype:CONST},
{input:"RR", tag:"mo", output:"\u211D", tex:null, ttype:CONST},
{input:"ZZ", tag:"mo", output:"\u2124", tex:null, ttype:CONST},
{input:"f", tag:"mi", output:"f", tex:null, ttype:UNARY, func:true},
{input:"g", tag:"mi", output:"g", tex:null, ttype:UNARY, func:true},
//standard functions
{input:"lim", tag:"mo", output:"lim", tex:null, ttype:UNDEROVER},
{input:"Lim", tag:"mo", output:"Lim", tex:null, ttype:UNDEROVER},
{input:"sin", tag:"mo", output:"sin", tex:null, ttype:UNARY, func:true},
{input:"cos", tag:"mo", output:"cos", tex:null, ttype:UNARY, func:true},
{input:"tan", tag:"mo", output:"tan", tex:null, ttype:UNARY, func:true},
{input:"sinh", tag:"mo", output:"sinh", tex:null, ttype:UNARY, func:true},
{input:"cosh", tag:"mo", output:"cosh", tex:null, ttype:UNARY, func:true},
{input:"tanh", tag:"mo", output:"tanh", tex:null, ttype:UNARY, func:true},
{input:"cot", tag:"mo", output:"cot", tex:null, ttype:UNARY, func:true},
{input:"sec", tag:"mo", output:"sec", tex:null, ttype:UNARY, func:true},
{input:"csc", tag:"mo", output:"csc", tex:null, ttype:UNARY, func:true},
{input:"arcsin", tag:"mo", output:"arcsin", tex:null, ttype:UNARY, func:true},
{input:"arccos", tag:"mo", output:"arccos", tex:null, ttype:UNARY, func:true},
{input:"arctan", tag:"mo", output:"arctan", tex:null, ttype:UNARY, func:true},
{input:"coth", tag:"mo", output:"coth", tex:null, ttype:UNARY, func:true},
{input:"sech", tag:"mo", output:"sech", tex:null, ttype:UNARY, func:true},
{input:"csch", tag:"mo", output:"csch", tex:null, ttype:UNARY, func:true},
{input:"exp", tag:"mo", output:"exp", tex:null, ttype:UNARY, func:true},
{input:"abs", tag:"mo", output:"abs", tex:null, ttype:UNARY, rewriteleftright:["|","|"]},
{input:"log", tag:"mo", output:"log", tex:null, ttype:UNARY, func:true},
{input:"ln", tag:"mo", output:"ln", tex:null, ttype:UNARY, func:true},
{input:"gcd", tag:"mo", output:"gcd", tex:null, ttype:UNARY, func:true},
{input:"lcm", tag:"mo", output:"lcm", tex:null, ttype:UNARY, func:true},
{input:"min", tag:"mo", output:"min", tex:null, ttype:UNDEROVER},
{input:"max", tag:"mo", output:"max", tex:null, ttype:UNDEROVER},
//arrows
{input:"uarr", tag:"mo", output:"\u2191", tex:"uparrow", ttype:CONST},
{input:"darr", tag:"mo", output:"\u2193", tex:"downarrow", ttype:CONST},
{input:"rarr", tag:"mo", output:"\u2192", tex:"rightarrow", ttype:CONST},
{input:"->", tag:"mo", output:"\u2192", tex:"to", ttype:CONST},
{input:">->", tag:"mo", output:"\u21A3", tex:"rightarrowtail", ttype:CONST},
{input:"->>", tag:"mo", output:"\u21A0", tex:"twoheadrightarrow", ttype:CONST},
{input:">->>", tag:"mo", output:"\u2916", tex:"twoheadrightarrowtail", ttype:CONST},
{input:"|->", tag:"mo", output:"\u21A6", tex:"mapsto", ttype:CONST},
{input:"larr", tag:"mo", output:"\u2190", tex:"leftarrow", ttype:CONST},
{input:"harr", tag:"mo", output:"\u2194", tex:"leftrightarrow", ttype:CONST},
{input:"rArr", tag:"mo", output:"\u21D2", tex:"Rightarrow", ttype:CONST},
{input:"lArr", tag:"mo", output:"\u21D0", tex:"Leftarrow", ttype:CONST},
{input:"hArr", tag:"mo", output:"\u21D4", tex:"Leftrightarrow", ttype:CONST},
//commands with argument
{input:"sqrt", tag:"msqrt", output:"sqrt", tex:null, ttype:UNARY},
{input:"root", tag:"mroot", output:"root", tex:null, ttype:BINARY},
{input:"frac", tag:"mfrac", output:"/", tex:null, ttype:BINARY},
{input:"/", tag:"mfrac", output:"/", tex:null, ttype:INFIX},
{input:"_", tag:"msub", output:"_", tex:null, ttype:INFIX},
{input:"^", tag:"msup", output:"^", tex:null, ttype:INFIX},
{input:"text", tag:"mtext", output:"text", tex:null, ttype:TEXT},
{input:"color", tag:"mstyle", ttype:BINARY},
{input:"cancel", tag:"menclose", output:"cancel", tex:null, ttype:UNARY}
);
});
</script>
It would also be possible to turn this into a configuration file that you could load rather than having to include it in each page directly.
I'm not sure all these are appropriate for your situation, but you can remove the ones you don't think are appropriate. Just be sure that you don't leave an extra comma at the end of the last one in the list
Finally, if you want things like "in" to be able to be used for inches, then you could add commands for them, like
{input:"in", tag:"mtext", output:"\u2006in", tex:null, ttype:CONST},
say at the top of the list. (Here the \u2006 is a character that represents a small amount of space.) You may need to include several other forms, as well, such as
{input:"in", tag:"mtext", output:"\u2006in", tex:null, ttype:CONST},
{input:"inch", tag:"mtext", output:"\u2006in", tex:null, ttype:CONST},
{input:"inches", tag:"mtext", output:"\u2006in", tex:null, ttype:CONST},
Include whatever units you might need.