There are three sensible ways of installing SWI-Prolog on MacOS X, in increasing order of complexity: Download the SWI-Prolog application. In this case, you just download a disk image, open it, and drag the application to your disk (e.g. To your Applications folder. You use the application as any other application by double-clicking on its icon. Backbone: Prologue is the first act of a noir roleplaying detective adventure. You are raccoon private eye Howard Lotor, a second-class citizen of dystopian Vancouver, BC inhabited by animals. Interrogate a diverse cast of characters, collect evidence, and choose which leads to follow. Prolog is a general purpose logic programming language that was released back in 1972, with very few updates since. Logtalk was created to add more modern features to Prolog, mainly performance improvements, lambda expressions, grammar rules, improved compiler errors.
Windows and Mac:
Linux (Ubuntu):
Quick start (Linux):
For more Getting started advice, please refer to the SWI-Prolog Tutorials.
1. How to Run Prolog
Other important prolog systems (Borland, XSB, LPA, Minerva ...) have been used for development and testing over the past 25 years. A new section of this tutorial is planned to describe prolog systemsin a general way, but that section is not available at this time.
SWI-Prolog's website has lots of information about SWI-Prolog, a downloadarea, and documentation. The upkeep for SWI-Prolog is excellent. The link ...
SWI-PrologHome Page (current as of August 2006)
The examples in this tutorial use a simplified form of interaction witha typical Prolog interpreter. The sample programs should executesimilarly on any system using an Edinburgh-style Prolog interpreter orinteractive compiler.
To start an interactive SWI-Prolog session under Unix, open a terminal window andtype the approprite command (indicated in the installation instructions). For example, on our Mac this is ...
$ /opt/local/bin/swipl
{We never type that last line: we employ Unix source files to start SWI-Prolog using additional command line arguments and/or switches for special purposes.The reader could explore this possibility soon after learning more prolog basics.}
Under Windows, SWI-Prolog installs a start icon that can be double-clickedto initiate the interpreter. The interpreter then starts in its own command window.
A startup message or banner may appear, and that will soon be followed bya goal prompt looking similar to the following
?- _Interactive goals in Prolog are entered by the user following the '?- ' prompt.
Many Prologs have command-line help information. SWI Prolog hasextensive help information. This help is indexed and guides the user. Tolearn more about it, try
Prolog Download Free?- help(help). Windows PrologNotice that all of the displayed symbols need to be typed in, followedby a carriage return.
To illustrate some particular interactions with prolog, consider thefollowing sample session. Each file referred to is assumed to be a localfile in the user's account, which was either created by the user, obtainedby copying directly from some other public source, or obtained by savinga text file while using a web browser. The way to achieve the latter iseither to follow a URL to the source file and then save, or to select textin a Prolog Tutorial web page, copy it, paste into a text editor windowand then save to file. The comments /* ... */ next to goals are referredto in the notes following the session.
Download Prolog For Windows 10The comments appearing at the right at various spots in a samplesession were added with a text processor. They also serve as referencesignposts for the notes which appear below. We discuss several points now, while other details will be deferred to later sections.
Notes:
1. A Prolog goal is terminated with a period '.' In this case the goalwas to load a program file. This 'bracket' style notation dates back tothe first Prolog implementations. Several files can be chain loaded bylisting the filenames sequentially within the brackets, separated by commas.In this case, the file's name is 2_1.pl (programs corresponding to Section7.1 of this tutorial), which contains two prolog programs for calculatingthe factorial of a positive integer. The actual program in the file isdiscussed in Section 2.1. The program file was located in the current directory.If it had not been, then the path to it would have to have been specifiedin the usual way.
2. The built-in predicate 'listing' will list the program in memory --in this case, the factorial program. The appearance of this listing isa little different than the appearance of the source code in the file,which we will see in Section 2.1. Actually, Quintus Prolog compiles programsunless predicates are declared to be dynamic. Compiled predicates do nothave an interactive source listing that can be supplied by a 'listing'goal. So, in order to illustrate this Prolog interpreter feature, the predicateswere declared as dynamic in the source code before this sample run.
3. The goal here, 'factorial(10,What)', essentially says 'the factorialof 10 is What?'. The word 'What' begins with an upper-case letter, denotinga logical variable. Prolog satisfies the goal by finding the value of thevariable 'What'.
4. Both 'programs' now reside in memory, from the two source files 2_1.pland 2_7.pl. The 2_7.pl file has many list processing definitions in it.(See Section 2.7.)
5. In the program just loaded is a definition of the logical predicate'takeout'. The goal 'takeout(X,[1,2,3,4],Y)' asks that X be taken out oflist [1,2,3,4] leaving remainder list Y, in all possible ways. There arefour ways to do this, as shown in the response. The 'takeout' predicateis discussed in Section 2.7. Note, however, how Prolog is prodded to produceall of the possible answers: After producing each answer, Prolog waitswith a cursor at the end of the answer. If the user types a semicolon ';', Prolog will look for a next answer, and so on. If the user just hitsEnter, then Prolog stops looking for answers.
6. A compound or conjunctive goal asks that two individual goals besatisfied. Note the arithmetic goal (built-in relation), 'X>3'. Prologwill attempt to satisfy these goals in the left-to-right order, just asthey would be read. In this case, there is only one answer. Note the useof an anonymous variable '_' in the goal, for which no binding is reported('don't-care variable').
7. The 'halt' goal always succeeds and returns the user to the operatingsystem.
Prolog Tutorial Contents
Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2020
Categories |