Clarified comments

lib/parser_block.js

@@ -60,6 +60,8 @@ ParserBlock.prototype.tokenize = function (state, startLine, endLine) {
     state.line = line = state.skipEmptyLines(line);
     if (line >= endLine) { break; }
 
+    // Termination condition for nested calls.
+    // Nested calls currently used for blockquotes & lists
     if (state.tShift[line] < state.blkIndent) { break; }
     if (state.bqMarks[line] < state.bqLevel) { break; }
 

lib/rules_block/state_block.js

@@ -29,15 +29,16 @@ function State(src, parser, tokens, options, env) {
   this.bMarks = [];  // line begin offsets for fast jumps
   this.eMarks = [];  // line end offsets for fast jumps
   this.tShift = [];  // indent for each line
-  this.bqMarks = []; // lines shifts in blockquotes (calculated on bq enter)
+  this.bqMarks = []; // blockquote nesting level for each line (number of '>')
 
   // block parser variables
-  this.blkIndent  = 0;
+  this.blkIndent  = 0; // required block content indent
+                       // (for example, if we are in list)
   this.line       = 0; // line index in src
   this.lineMax    = 0; // lines count
   this.tight      = false; // loose/tight mode for lists
   this.listMode   = false; // if true, block parser stops on two newlines
-  this.bqLevel    = 0; // blockquote nesting level
+  this.bqLevel    = 0; // blockquote nesting level for currently tokenized block
 
   this.level = 0;