Evaluating AST Tree of PostCSS

index.js

var postcss = require('postcss'),
  fs = require('fs'),
  path = require('path'),
  css = fs.readFileSync(path.join(__dirname, 'lesstest.less'), 'utf-8'),
  root = postcss.parse(css);

console.log(require('util').inspect(root, { depth: 6 }));

input.css

.foo {
  border: none;
}

input2.css

.mixin (...) {
  &[input],
  [input]& {
    border: 0;
  }
}

result-ast-2.js

{ raws: { semicolon: false, after: '\n' },
  type: 'root',
  nodes: 
   [ { raws: { before: '', between: ' ', semicolon: false, after: '\n' },
       type: 'rule',
       nodes: 
        [ { raws: { before: '\n  ', between: ' ', semicolon: true, after: '\n  ' },
            type: 'rule',
            nodes: 
             [ { raws: { before: '\n    ', between: ': ' },
                 type: 'decl',
                 parent: [Circular],
                 source: 
                  { start: { line: 4, column: 5 },
                    input: 
                     { css: '.mixin (...) {\n  &[input],\n  [input]& {\n    border: 0;\n  }\n}\n',
                       id: '<input css 1>' },
                    end: { line: 4, column: 14 } },
                 prop: 'border',
                 value: '0' } ],
            parent: [Circular],
            source: 
             { start: { line: 2, column: 3 },
               input: 
                { css: '.mixin (...) {\n  &[input],\n  [input]& {\n    border: 0;\n  }\n}\n',
                  id: '<input css 1>' },
               end: { line: 5, column: 3 } },
            selector: '&[input],\n  [input]&' } ],
       parent: [Circular],
       source: 
        { start: { line: 1, column: 1 },
          input: 
           { css: '.mixin (...) {\n  &[input],\n  [input]& {\n    border: 0;\n  }\n}\n',
             id: '<input css 1>' },
          end: { line: 6, column: 1 } },
       selector: '.mixin (...)' } ],
  source: 
   { input: 
      { css: '.mixin (...) {\n  &[input],\n  [input]& {\n    border: 0;\n  }\n}\n',
        id: '<input css 1>' },
     start: { line: 1, column: 1 } } }

result-ast.js

{ raws: { semicolon: false, after: '\n' },
  type: 'root',
  nodes: 
   [ { raws: { before: '', between: ' ', semicolon: true, after: '\n' },
       type: 'rule',
       nodes: 
        [ { raws: { before: '\n  ', between: ': ' },
            type: 'decl',
            parent: [Circular],
            source: 
             { start: { line: 2, column: 3 },
               input: { css: '.foo {\n  border: none;\n}\n', id: '<input css 1>' },
               end: { line: 2, column: 15 } },
            prop: 'border',
            value: 'none' } ],
       parent: [Circular],
       source: 
        { start: { line: 1, column: 1 },
          input: { css: '.foo {\n  border: none;\n}\n', id: '<input css 1>' },
          end: { line: 3, column: 1 } },
       selector: '.foo' } ],
  source: 
   { input: { css: '.foo {\n  border: none;\n}\n', id: '<input css 1>' },
     start: { line: 1, column: 1 } } }