code: function NixIf(args) {
      this.ifExpr = args.ifExpr;
      this.thenExpr = args.thenExpr;
      this.elseExpr = args.elseExpr;
  }
docs: Creates a new NixIf instance.
  
  @class NixIf
  @extends NixBlock
  @classdesc Captures the abstract syntax of a Nix of if-then-else statement.
  
  @constructor
  @param {Object} args Arguments to this function
  @param {Mixed} args.ifExpr An object representing an expression evaluating to a boolean
  @param {Mixed} args.thenExpr Expression that gets evaluated if the condition is true
  @param {Mixed} args.elseExpr Expression that gets evaluated if the condition is false