How do I trace a query in Prolog?

How do I trace a query in Prolog?

To activate the graphical debugger, click on Debug, Graphical Debugger on the menu. Then type the trace command followed by the query. Press the spacebar to follow the pretty colours and the logic.

Which command is used to debug the Prolog program?

Elementary use of the debugger: SICStus Prolog uses a fairly standard Prolog debugging environment. You will need the debugger to follow the working of your programs when they behave wrongly. You can also use debugging tools to understand how example programs work. The simplest command is trace.

How do you use SWI in Prolog?

  1. Write a prolog program as a text file with a .
  2. Open a terminal (Ctrl+Alt+T) and navigate to the directory where you stored your program.
  3. Open SWI-Prolog by invoking swipl .
  4. In SWI-Prolog, type [program] to load the program, i.e. the file name in brackets, but without the ending.

What does creep mean in Prolog?

* What is this “creep” business? In SWI Prolog, the implementation of Prolog which this dictionary uses for the syntax of its examples, when you press return at the end of a line of tracing, Prolog prints “creep” on the same line, and then prints the next line of trace output on the next line.

How do you stop a trace in Prolog?

A CTRL-d or the atom end_of_file followed by a period terminates the input stream. If you want to exit SWI-Prolog, issue the command halt., or simply type CTRL-d at the SWI-Prolog prompt.

How do you create a list in Prolog?

In Prolog list elements are enclosed by brackets and separated by commas. Another way to represent a list is to use the head/tail notation [H|T]. Here the head of the list, H, is separated from the tail of the list, T, by a vertical bar. The tail of a list is the original list with its first element removed.

How do you program a Prolog?

To create a program in Prolog, the simple way is to type it into the text editor and then save it as a text file like The following example shows a simple program of Prolog. The program contains three components, which are known as clauses. Each clause is terminated using a full stop.

Is SWI-Prolog open source?

SWI-Prolog offers a comprehensive free Prolog environment. Since its start in 1987, SWI-Prolog development has been driven by the needs of real world applications.

How do you run a function in Prolog?

When you have finished your code, do the following steps to run your code:

  1. Step 1: open your prolog terminal. (See pic1)
  2. Step 2: click “File” on the left of the top, then choose “Consult” to open the prolog file(your code file). (See pic2)
  3. Step 3: type in your function name and parameters.

How do I quit Prolog?

If you want to exit SWI-Prolog, issue the command halt., or simply type CTRL-d at the SWI-Prolog prompt.