asciimathml.js

数值计算方法网络课件系统是浙江大学过程装备与控制工程专业2001级本科生毕业设计成果。本系统采用ASP＋ACCESS架构

//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:"\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
AMsqrt, AMroot, AMfrac, AMdiv, AMover, AMsub, AMsup,
{input:"hat", tag:"mover", output:"\u005E", tex:null, ttype:UNARY, acc:true},
{input:"bar", tag:"mover", output:"\u00AF", tex:"overline", ttype:UNARY, acc:true},
{input:"vec", tag:"mover", output:"\u2192", tex:null, ttype:UNARY, acc:true},
{input:"dot", tag:"mover", output:".",      tex:null, ttype:UNARY, acc:true},
{input:"ddot", tag:"mover", output:"..",    tex:null, ttype:UNARY, acc:true},
{input:"ul", tag:"munder", output:"\u0332", tex:"underline", ttype:UNARY, acc:true},
AMtext, AMmbox, AMquote,
{input:"bb", tag:"mstyle", atname:"fontweight", atval:"bold", output:"bb", tex:null, ttype:UNARY},
{input:"mathbf", tag:"mstyle", atname:"fontweight", atval:"bold", output:"mathbf", tex:null, ttype:UNARY},
{input:"sf", tag:"mstyle", atname:"fontfamily", atval:"sans-serif", output:"sf", tex:null, ttype:UNARY},
{input:"mathsf", tag:"mstyle", atname:"fontfamily", atval:"sans-serif", output:"mathsf", tex:null, ttype:UNARY},
{input:"bbb", tag:"mstyle", atname:"mathvariant", atval:"double-struck", output:"bbb", tex:null, ttype:UNARY, codes:AMbbb},
{input:"mathbb", tag:"mstyle", atname:"mathvariant", atval:"double-struck", output:"mathbb", tex:null, ttype:UNARY, codes:AMbbb},
{input:"cc",  tag:"mstyle", atname:"mathvariant", atval:"script", output:"cc", tex:null, ttype:UNARY, codes:AMcal},
{input:"mathcal", tag:"mstyle", atname:"mathvariant", atval:"script", output:"mathcal", tex:null, ttype:UNARY, codes:AMcal},
{input:"tt",  tag:"mstyle", atname:"fontfamily", atval:"monospace", output:"tt", tex:null, ttype:UNARY},
{input:"mathtt", tag:"mstyle", atname:"fontfamily", atval:"monospace", output:"mathtt", tex:null, ttype:UNARY},
{input:"fr",  tag:"mstyle", atname:"mathvariant", atval:"fraktur", output:"fr", tex:null, ttype:UNARY, codes:AMfrk},
{input:"mathfrak",  tag:"mstyle", atname:"mathvariant", atval:"fraktur", output:"mathfrak", tex:null, ttype:UNARY, codes:AMfrk}
];

function compareNames(s1,s2) {
  if (s1.input > s2.input) return 1
  else return -1;
}

var AMnames = []; //list of input symbols

function AMinitSymbols() {
  var texsymbols = [], i;
  for (i=0; i<AMsymbols.length; i++)
    if (AMsymbols[i].tex) 
      texsymbols[texsymbols.length] = {input:AMsymbols[i].tex, 
        tag:AMsymbols[i].tag, output:AMsymbols[i].output, ttype:AMsymbols[i].ttype};
  AMsymbols = AMsymbols.concat(texsymbols);
  AMsymbols.sort(compareNames);
  for (i=0; i<AMsymbols.length; i++) AMnames[i] = AMsymbols[i].input;
}

var AMmathml = "http://www.w3.org/1998/Math/MathML";

function AMcreateElementMathML(t) {
  if (isIE) return document.createElement("mml:"+t);
  else return document.createElementNS(AMmathml,t);
}

function AMcreateMmlNode(name,frag) {
  var node = AMcreateElementMathML(name);
  node.appendChild(frag);
  return node;
}

function AMremoveCharsAndBlanks(str,n) {
//remove n characters and any following blanks
  var st;
  if (str.charAt(n)=="\\" && str.charAt(n+1)!="\\" && str.charAt(n+1)!=" ") 
    st = str.slice(n+1);
  else st = str.slice(n);
  for (var i=0; i<st.length && st.charCodeAt(i)<=32; i=i+1);
  return st.slice(i);
}

function AMposition(arr, str, n) { 
// return position >=n where str appears or would be inserted
// assumes arr is sorted
  if (n==0) {
    var h,m;
    n = -1;
    h = arr.length;
    while (n+1<h) {
      m = (n+h) >> 1;
      if (arr[m]<str) n = m; else h = m;
    }
    return h;
  } else
    for (var i=n; i<arr.length && arr[i]<str; i++);
  return i; // i=arr.length || arr[i]>=str
}

var AMseparated = true;

function AMgetSymbol(str) {
//return maximal initial substring of str that appears in names
//return null if there is none
  var k = 0; //new pos
  var j = 0; //old pos
  var mk; //match pos
  var st;
  var tagst;
  var match = "";
  var more = true;
  for (var i=1; i<=str.length && more; i++) {
    st = str.slice(0,i); //initial substring of length i
    j = k;
    k = AMposition(AMnames, st, j);
    if (k<AMnames.length && str.slice(0,AMnames[k].length)==AMnames[k]){
      match = AMnames[k];
      mk = k;
      i = match.length;
    }
    more = k<AMnames.length && str.slice(0,AMnames[k].length)>=AMnames[k];
  }
  if (match!="")
    if (separatetokens) {
      i = match.length;
      if ("a">str.charAt(0) || str.charAt(0)>"z" || 
        "a">str.charAt(i-1) || str.charAt(i-1)>"z") {
        AMseparated = true;
        return AMsymbols[mk];
      }
      st = str.charAt(i);
      AMseparated = AMseparated && ("a">st || st>"z");
      if (AMseparated) return AMsymbols[mk];
    } else return AMsymbols[mk]; 
// if str[0] is a digit or - return maxsubstring of digits.digits
  k = 1;
  st = str.slice(0,1);
  var pos = true;
  var integ = true;
  if (st == "-") {
    pos = false;
    st = str.slice(k,k+1);
    k++;
  }
  while ("0"<=st && st<="9" && k<=str.length) {
    st = str.slice(k,k+1);
    k++;
  }
  if (st == ".") {
    integ = false;
    st = str.slice(k,k+1);
    k++;
    while ("0"<=st && st<="9" && k<=str.length) {
      st = str.slice(k,k+1);
      k++;
    }
  }
  if ((pos && integ && k>1) || ((pos || integ) && k>2) || k>3) {
    st = str.slice(0,k-1);
    tagst = "mn";
    AMseparated = true;
  } else {
    k = 2;
    st = str.slice(0,1); //take 1 character
    AMseparated = ("A">st || st>"Z") && ("a">st || st>"z");
    tagst = (AMseparated?"mo":"mi");
    AMseparated = AMseparated || str.charAt(1)<"a" || str.charAt(1)>"z";
  }
  return {input:str.slice(0,k-1), tag:tagst, output:st, ttype:CONST};
}

function AMremoveBrackets(node) {
  var st;
  if (node.nodeName=="mrow") {
    st = node.firstChild.firstChild.nodeValue;
    if (st=="(" || st=="[" || st=="{") node.removeChild(node.firstChild);
  }
  if (node.nodeName=="mrow") {
    st = node.lastChild.firstChild.nodeValue;
    if (st==")" || st=="]" || st=="}") node.removeChild(node.lastChild);
  }
}

/*Parsing ASCII math expressions with the following grammar
V ::= [A-Za-z] | greek letters | numbers | other constant symbols
U ::= sqrt | text | bb | other unary symbols for font commands
B ::= frac | root | stackrel         binary symbols
L ::= ( | [ | { | (: | {:            left brackets
R ::= ) | ] | } | :) | :}            right brackets
S ::= V | LER | US | BSS             simple expression
E ::= SE | S/S | S_S | S^S | S_S^S   expression
Each terminal symbol is translated into a corresponding mathml node.*/

var AMnestingDepth;

function AMparseSexpr(str) { //parses str and returns [node,tailstr]
  var symbol, node, result, i, st, newFrag = document.createDocumentFragment();
  str = AMremoveCharsAndBlanks(str,0);
  symbol = AMgetSymbol(str);             //either a token or a bracket or empty
  if (symbol == null || symbol.ttype == RIGHTBRACKET && AMnestingDepth > 0)
    return [null,str];
  if (symbol.ttype == DEFINITION) {
    str = symbol.output+AMremoveCharsAndBlanks(str,symbol.input.length); 
    symbol = AMgetSymbol(str);
  }
  switch (symbol.ttype) {
  case UNDEROVER:
  case CONST:
    str = AMremoveCharsAndBlanks(str,symbol.input.length); 
    if (symbol.tag=="mn" && symbol.output.charAt(0)=="-") {
      node = AMcreateMmlNode("mo",document.createTextNode("-"));
      node = AMcreateMmlNode("mrow",node);
      node.appendChild(AMcreateMmlNode(symbol.tag,        //its a constant
                             document.createTextNode(symbol.output.slice(1))));
      return [node,str];
    } else
    return [AMcreateMmlNode(symbol.tag,        //its a constant
                             document.createTextNode(symbol.output)),str];
  case LEFTBRACKET:   //read (expr+)
    AMnestingDepth++;
    str = AMremoveCharsAndBlanks(str,symbol.input.length); 
    result = AMparseExpr(str);
    if (typeof symbol.invisible == "boolean" && symbol.invisible) 
      node = AMcreateMmlNode("mrow",result[0]);
    else {
      node = AMcreateMmlNode("mo",document.createTextNode(symbol.output));
      node = AMcreateMmlNode("mrow",node);
      node.appendChild(result[0]);
    }
    return [node,result[1]];
  case UNARY:
    if (symbol == AMtext || symbol == AMmbox || symbol == AMquote) {
      if (symbol!=AMquote) str = AMremoveCharsAndBlanks(str,symbol.input.length);
      if (str.charAt(0)=="{") i=str.indexOf("}");
      else if (str.charAt(0)=="(") i=str.indexOf(")");
      else if (str.charAt(0)=="[") i=str.indexOf("]");
      else if (symbol==AMquote) i=str.slice(1).indexOf("\"")+1;
      else i = 0;
      if (i==-1) i = str.length;
      st = str.slice(1,i);
      if (st.charAt(0) == " ") {
        node = AMcreateElementMathML("mspace");
        node.setAttribute("width","1ex");
        newFrag.appendChild(node);
      }
      newFrag.appendChild(
        AMcreateMmlNode(symbol.tag,document.createTextNode(st)));
      if (st.charAt(st.length-1) == " ") {
        node = AMcreateElementMathML("mspace");
        node.setAttribute("width","1ex");
        newFrag.appendChild(node);
      }
      str = AMremoveCharsAndBlanks(str,i+1);
      return [AMcreateMmlNode("mrow",newFrag),str];
    } else {
      str = AMremoveCharsAndBlanks(str,symbol.input.length); 
      result = AMparseSexpr(str);
      if (result[0]==null) return [AMcreateMmlNode("mo",
                             document.createTextNode(symbol.input)),str];
      AMremoveBrackets(result[0]);
      if (symbol == AMsqrt) {           // sqrt
        return [AMcreateMmlNode(symbol.tag,result[0]),result[1]];
      } else if (typeof symbol.acc == "boolean" && symbol.acc) {   // accent
        node = AMcreateMmlNode(symbol.tag,result[0]);
        node.appendChild(AMcreateMmlNode("mo",document.createTextNode(symbol.output)));
        return [node,result[1]];
      } else {                        // font change command