text: // CodeMirror, copyright (c) by Marijn Haverbeke and others
  // Distributed under an MIT license: http://codemirror.net/LICENSE
  
  /**
   * Author: Koh Zi Han, based on implementation by Koh Zi Chun
   */
  
  (function(mod) {
    if (typeof exports == "object" && typeof module == "object") // CommonJS
      mod(require("../../lib/codemirror"));
    else if (typeof define == "function" && define.amd) // AMD
      define(["../../lib/codemirror"], mod);
    else // Plain browser env
      mod(CodeMirror);
  })(function(CodeMirror) {
  "use strict";
  
  CodeMirror.defineMode("scheme", function () {
      var BUILTIN = "builtin", COMMENT = "comment", STRING = "string",
          ATOM = "atom", NUMBER = "number", BRACKET = "bracket";
      var INDENT_WORD_SKIP = 2;
  
      function makeKeywords(str) {
          var obj = {}, words = str.split(" ");
          for (var i = 0; i < words.length; ++i) obj[words[i]] = true;
          return obj;
      }
  
      var keywords = makeKeywords("λ case-lambda call/cc class define-class exit-handler field import inherit init-field interface let*-values let-values let/ec mixin opt-lambda override protect provide public rename require require-for-syntax syntax syntax-case syntax-error unit/sig unless when with-syntax and begin call-with-current-continuation call-with-input-file call-with-output-file case cond define define-syntax delay do dynamic-wind else for-each if lambda let let* let-syntax letrec letrec-syntax map or syntax-rules abs acos angle append apply asin assoc assq assv atan boolean? caar cadr call-with-input-file call-with-output-file call-with-values car cdddar cddddr cdr ceiling char->integer char-alphabetic? char-ci<=? char-ci<? char-ci=? char-ci>=? char-ci>? char-downcase char-lower-case? char-numeric? char-ready? char-upcase char-upper-case? char-whitespace? char<=? char<? char=? char>=? char>? char? close-input-port close-output-port complex? cons cos current-input-port current-output-port denominator display eof-object? eq? equal? eqv? eval even? exact->inexact exact? exp expt #f floor force gcd imag-part inexact->exact inexact? input-port? integer->char integer? interaction-environment lcm length list list->string list->vector list-ref list-tail list? load log magnitude make-polar make-rectangular make-string make-vector max member memq memv min modulo negative? newline not null-environment null? number->string number? numerator odd? open-input-file open-output-file output-port? pair? peek-char port? positive? procedure? quasiquote quote quotient rational? rationalize read read-char real-part real? remainder reverse round scheme-report-environment set! set-car! set-cdr! sin sqrt string string->list string->number string->symbol string-append string-ci<=? string-ci<? string-ci=? string-ci>=? string-ci>? string-copy string-fill! string-length string-ref string-set! string<=? string<? string=? string>=? string>? string? substring symbol->string symbol? #t tan transcript-off transcript-on truncate values vector vector->list vector-fill! vector-length vector-ref vector-set! with-input-from-file with-output-to-file write write-char zero?");
      var indentKeys = makeKeywords("define let letrec let* lambda");
  
      function stateStack(indent, type, prev) { // represents a state stack object
          this.indent = indent;
          this.type = type;
          this.prev = prev;
      }
  
      function pushStack(state, indent, type) {
          state.indentStack = new stateStack(indent, type, state.indentStack);
      }
  
      function popStack(state) {
          state.indentStack = state.indentStack.prev;
      }
  
      var binaryMatcher = new RegExp(/^(?:[-+]i|[-+][01]+#*(?:\/[01]+#*)?i|[-+]?[01]+#*(?:\/[01]+#*)?@[-+]?[01]+#*(?:\/[01]+#*)?|[-+]?[01]+#*(?:\/[01]+#*)?[-+](?:[01]+#*(?:\/[01]+#*)?)?i|[-+]?[01]+#*(?:\/[01]+#*)?)(?=[()\s;"]|$)/i);
      var octalMatcher = new RegExp(/^(?:[-+]i|[-+][0-7]+#*(?:\/[0-7]+#*)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?@[-+]?[0-7]+#*(?:\/[0-7]+#*)?|[-+]?[0-7]+#*(?:\/[0-7]+#*)?[-+](?:[0-7]+#*(?:\/[0-7]+#*)?)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?)(?=[()\s;"]|$)/i);
      var hexMatcher = new RegExp(/^(?:[-+]i|[-+][\da-f]+#*(?:\/[\da-f]+#*)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?@[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?[-+](?:[\da-f]+#*(?:\/[\da-f]+#*)?)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?)(?=[()\s;"]|$)/i);
      var decimalMatcher = new RegExp(/^(?:[-+]i|[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)i|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)@[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)?i|(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*))(?=[()\s;"]|$)/i);
  
      function isBinaryNumber (stream) {
          return stream.match(binaryMatcher);
      }
  
      function isOctalNumber (stream) {
          return stream.match(octalMatcher);
      }
  
      function isDecimalNumber (stream, backup) {
          if (backup === true) {
              stream.backUp(1);
          }
          return stream.match(decimalMatcher);
      }
  
      function isHexNumber (stream) {
          return stream.match(hexMatcher);
      }
  
      return {
          startState: function () {
              return {
                  indentStack: null,
                  indentation: 0,
                  mode: false,
                  sExprComment: false
              };
          },
  
          token: function (stream, state) {
              if (state.indentStack == null && stream.sol()) {
                  // update indentation, but only if indentStack is empty
                  state.indentation = stream.indentation();
              }
  
              // skip spaces
              if (stream.eatSpace()) {
                  return null;
              }
              var returnType = null;
  
              switch(state.mode){
                  case "string": // multi-line string parsing mode
                      var next, escaped = false;
                      while ((next = stream.next()) != null) {
                          if (next == "\"" && !escaped) {
  
                              state.mode = false;
                              break;
                          }
                          escaped = !escaped && next == "\\";
                      }
                      returnType = STRING; // continue on in scheme-string mode
                      break;
                  case "comment": // comment parsing mode
                      var next, maybeEnd = false;
                      while ((next = stream.next()) != null) {
                          if (next == "#" && maybeEnd) {
  
                              state.mode = false;
                              break;
                          }
                          maybeEnd = (next == "|");
                      }
                      returnType = COMMENT;
                      break;
                  case "s-expr-comment": // s-expr commenting mode
                      state.mode = false;
                      if(stream.peek() == "(" || stream.peek() == "["){
                          // actually start scheme s-expr commenting mode
                          state.sExprComment = 0;
                      }else{
                          // if not we just comment the entire of the next token
                          stream.eatWhile(/[^/s]/); // eat non spaces
                          returnType = COMMENT;
                          break;
                      }
                  default: // default parsing mode
                      var ch = stream.next();
  
                      if (ch == "\"") {
                          state.mode = "string";
                          returnType = STRING;
  
                      } else if (ch == "'") {
                          returnType = ATOM;
                      } else if (ch == '#') {
                          if (stream.eat("|")) {                    // Multi-line comment
                              state.mode = "comment"; // toggle to comment mode
                              returnType = COMMENT;
                          } else if (stream.eat(/[tf]/i)) {            // #t/#f (atom)
                              returnType = ATOM;
                          } else if (stream.eat(';')) {                // S-Expr comment
                              state.mode = "s-expr-comment";
                              returnType = COMMENT;
                          } else {
                              var numTest = null, hasExactness = false, hasRadix = true;
                              if (stream.eat(/[ei]/i)) {
                                  hasExactness = true;
                              } else {
                                  stream.backUp(1);       // must be radix specifier
                              }
                              if (stream.match(/^#b/i)) {
                                  numTest = isBinaryNumber;
                              } else if (stream.match(/^#o/i)) {
                                  numTest = isOctalNumber;
                              } else if (stream.match(/^#x/i)) {
                                  numTest = isHexNumber;
                              } else if (stream.match(/^#d/i)) {
                                  numTest = isDecimalNumber;
                              } else if (stream.match(/^[-+0-9.]/, false)) {
                                  hasRadix = false;
                                  numTest = isDecimalNumber;
                              // re-consume the intial # if all matches failed
                              } else if (!hasExactness) {
                                  stream.eat('#');
                              }
                              if (numTest != null) {
                                  if (hasRadix && !hasExactness) {
                                      // consume optional exactness after radix
                                      stream.match(/^#[ei]/i);
                                  }
                                  if (numTest(stream))
                                      returnType = NUMBER;
                              }
                          }
                      } else if (/^[-+0-9.]/.test(ch) && isDecimalNumber(stream, true)) { // match non-prefixed number, must be decimal
                          returnType = NUMBER;
                      } else if (ch == ";") { // comment
                          stream.skipToEnd(); // rest of the line is a comment
                          returnType = COMMENT;
                      } else if (ch == "(" || ch == "[") {
                        var keyWord = ''; var indentTemp = stream.column(), letter;
                          /**
                          Either
                          (indent-word ..
                          (non-indent-word ..
                          (;something else, bracket, etc.
                          */
  
                          while ((letter = stream.eat(/[^\s\(\[\;\)\]]/)) != null) {
                              keyWord += letter;
                          }
  
                          if (keyWord.length > 0 && indentKeys.propertyIsEnumerable(keyWord)) { // indent-word
  
                              pushStack(state, indentTemp + INDENT_WORD_SKIP, ch);
                          } else { // non-indent word
                              // we continue eating the spaces
                              stream.eatSpace();
                              if (stream.eol() || stream.peek() == ";") {
                                  // nothing significant after
                                  // we restart indentation 1 space after
                                  pushStack(state, indentTemp + 1, ch);
                              } else {
                                  pushStack(state, indentTemp + stream.current().length, ch); // else we match
                              }
                          }
                          stream.backUp(stream.current().length - 1); // undo all the eating
  
                          if(typeof state.sExprComment == "number") state.sExprComment++;
  
                          returnType = BRACKET;
                      } else if (ch == ")" || ch == "]") {
                          returnType = BRACKET;
                          if (state.indentStack != null && state.indentStack.type == (ch == ")" ? "(" : "[")) {
                              popStack(state);
  
                              if(typeof state.sExprComment == "number"){
                                  if(--state.sExprComment == 0){
                                      returnType = COMMENT; // final closing bracket
                                      state.sExprComment = false; // turn off s-expr commenting mode
                                  }
                              }
                          }
                      } else {
                          stream.eatWhile(/[\w\$_\-!$%&*+\.\/:<=>?@\^~]/);
  
                          if (keywords && keywords.propertyIsEnumerable(stream.current())) {
                              returnType = BUILTIN;
                          } else returnType = "variable";
                      }
              }
              return (typeof state.sExprComment == "number") ? COMMENT : returnType;
          },
  
          indent: function (state) {
              if (state.indentStack == null) return state.indentation;
              return state.indentStack.indent;
          },
  
          closeBrackets: {pairs: "()[]{}\"\""},
          lineComment: ";;"
      };
  });
  
  CodeMirror.defineMIME("text/x-scheme", "scheme");
  
  });
  