Julian Monteiro wrote:
> I'm trying do make a Robot which interpretate Javascript pages.
HTML is a STRUCTURAL language. It describes the STRUCTURE of a document. A robot
can analyze and validate the structure to see if it conforms to the rules of the
language. It can also extract "meaning" (e.g. a link) from the document because
the structure defines what the parts "mean".
JavaScript (and Java) are PROCEDURAL languages. They can make branching
decisions and execute loops. A robot could validate the syntax of the language,
but to find out what it "means" (e.g. to extract links for a spider) the robot
would have to execute or emulate the instructions. In other words, a badly coded
web page could put your robot into an infinite loop.
Also, for your robot to fully examine the "meaning" of the program, it would
have to follow BOTH SIDES of each branch in the logic, to see where it leads.
This quickly creates a nearly infinite group of permutations in all but the
simplest programs.
Anyone intending to develop (or ask someone else to develop) a JavaScript
"interpretater" needs to consider these issues and realize that reliably
extracting the "meaning" from program source code is a computationally
prohibitive task.
To put it another way, a compiler can identify syntax errors in a program. So
could a robot. But to find logic errors (or the outcome of correct logic) you
have to actually run the code.
So what is it you want this "interpretater" to produce?
