Fixed some typos, added comments.

.gitignore

@@ -147,3 +147,6 @@ tramp
 Session.vim
 .netrwhist
 *~
+
+# JFlex
+src/main/jflex/chocopy/pa1/ChocoPyLexer.java

src/main/jflex/chocopy/pa1/ChocoPy.jflex

@@ -32,9 +32,10 @@ import java.util.ArrayList;
 
     /** Producer of token-related values for the parser. */
     final ComplexSymbolFactory symbolFactory = new ComplexSymbolFactory();
-    private int currIndent = 0;
+    private int currIndent = 0; //Current Indentation Level
     private int currString = "";
-    private ArrayList<Integer> stack = new ArrayList<Integer>(20);
+    /*A stack that keeps track of the spaces in each Indentation Level*/
+    private ArrayList<Integer> stack = new ArrayList<Integer>(20); 
     /** Return a terminal symbol of syntactic category TYPE and no
      *  semantic value at the current source location. */
     private Symbol symbol(int type) {
@@ -57,7 +58,7 @@ import java.util.ArrayList;
         return stack.remove(stack.size() - 1);
     }
     private int top(){
-        if(stack.isEmpty) return 0;
+        if(stack.isEmpty()) return 0;
         return stack.get(stack.size() - 1);
     }
 %}
@@ -67,39 +68,74 @@ import java.util.ArrayList;
 WhiteSpace = [ \t]
 LineBreak  = \r|\n|\r\n
 
-IntegerLiteral = 0|[1-9][0-9]*
-StringLiteral = ([^\"\\]|(\\\")|(\\t)|(\\r)|(\\n)|(\\\\))*
-Names = (_|[a-z]|[A-Z])(_|[a-z]|[A-Z])*
+IntegerLiteral = 0|[1-9][0-9]* // Accroding to the manual, 00+ is illeagal
+StringLiteral = ([^\"\\]|(\\\")|(\\t)|(\\r)|(\\n)|(\\\\))* // \n, \r, \t, \\, \" and Anything except \ and " 
+Identifiers = (_|[a-z]|[A-Z])(_|[a-z]|[A-Z][0-9])* 
 Comments = #[^\r\n]*
 %%
 
 <YYINITIAL>{
   {WhiteSpace}                
   { 
-      String space = yytext();
-      if(space == "\t")
-        currIndent += 8;
+      /*Add indentation */
+      if(yytext() == "\t")
+        currIndent += 8; //'\t' = 8 spaces
       else 
         currIndent ++;
   }
-  {LineBreak}
+/*
+# This python code will test if '\t' is 8 spaces
+# It will run and print '1\n2'
+# Please tell me if your Python reports an error
+# Or you find documentations that says otherwise
+
+if True:
+    print(1) # \t
+        print(2) # 8 spaces
+*/
+  
+  {LineBreak} 
   {
+      /*
+      If this is a blank line, start over on the next line.
+      An empty line should just be ignored, therefore we don't 
+      pass a NEWLINE to Cup.
+      */
       currIndent = 0;
   }
-  {Comments}           { /* ignored */ }
-  [^ \t\r\n#]               
+  {Comments}           { /* ignored */ } //Ignore blank lines
+
+  /*If it's not a blank line (Current character isn't a 
+    Whitespace/linebreak/comment), deal with indentation here and 
+    start accepting whatever is on this line in `AFTER' state*/
+  [^ \t\r\n#] 
   {
+      //rewind the current character.
       yypushback(1);
       if(top() > currIndent)
-      {    
+      {   
+          /*
+          If the indentation of the line < indents current level should have,
+          keep dedenting until it reaches the right level.
+          It's like a loop, because we're not changing the state 
+          and we rewinded the current character. So it will keep 
+          going until top()<= currIndent and it will switch to 
+          AFTER state.
+          */ 
           pop();
-          return symbol(ChocoPyTokens.DEDENT);
+          return symbol(ChocoPyTokens.DEDENT, currIndent);
       }
+      /*Otherwise, we will start dealing with the rest 
+        of the line after indentation in from the next token.*/
       yystart(AFTER);
       if(top()< currIndent)
-      {
+      {   
+          /*
+          If current indentation > indents current level should have, 
+          start a new level which will have `currIndent' spaces.
+          */
           push(currIndent);
-          return symbol(ChocoPyTokens.INDENT);
+          return symbol(ChocoPyTokens.INDENT, currIndent);
       }
   }
 }
@@ -113,8 +149,7 @@ Comments = #[^\r\n]*
   /* Literals. */
   {IntegerLiteral}            { return symbol(ChocoPyTokens.NUMBER,
                                                  Integer.parseInt(yytext())); }
-//  {StringLiteral}             { return symbol(ChocoPyTokens.STRING, yytext());}
-  "\""                           {yystart(STR); currString = "";} 
+  "\""                           {yystart(STR); currString = "";} //Start taking a string when see a "
   "False"                        { return symbol(ChocoPyTokens.BOOL, false); }
   "True"                         { return symbol(ChocoPyTokens.BOOL, true); }
   "None"                         { return symbol(ChocoPyTokens.NONE); }
@@ -154,7 +189,7 @@ Comments = #[^\r\n]*
   "-"                         { return symbol(ChocoPyTokens.MINUS); }
   "*"                         { return symbol(ChocoPyTokens.MUL); }
   "//"                         { return symbol(ChocoPyTokens.DIV); }  
-  "/"                         { return symbol(ChocoPyTokens.DIV); }  
+  "/"                         { return symbol(ChocoPyTokens.DIV); }  //Accroding to manual, chocopy don't have fp division, '/', '//' should be integr division
   "%"                         { return symbol(ChocoPyTokens.MOD); }  
   ">"                         { return symbol(ChocoPyTokens.GT); }
   "<"                         { return symbol(ChocoPyTokens.LT); }
@@ -176,16 +211,16 @@ Comments = #[^\r\n]*
   
  
   /*Identifiers*/
-  {Names}                     {return symbol(ChocoPyTokens.NAMES, yytext());}
+  {Identifiers}                     {return symbol(ChocoPyTokens.ID, yytext());}
   /* Whitespace. */
   {WhiteSpace}                { /* ignore */ }
   /* Comment. */
   {Comments}                  { /* ignore */ }
 }
 <STR>{
-    {StringLiteral}           {currString+=yytext();}
+    {StringLiteral}           {currString += yytext();}
     \\$                       { /*'\' at the end of line, do nothing.*/ }
-    "\""                      {yybegin(AFTER); return symbol(ChocoPyTokens.STRING, currString);}
+    "\""                      {yybegin(AFTER); return symbol(ChocoPyTokens.STRING, currString);} // accepted a ", return to AFTER state
 }
 <<EOF>>                       { return symbol(ChocoPyTokens.EOF); }