TEACH PRIMER -- AN OVERVIEW OF POP-11

(Second Edition)

Aaron Sloman

School of Computer Science, The University of Birmingham

With help from the Poplog development team

Updated For Poplog V15.01, Jan 1996

Minimal Model of Pop-11 added before Chapter 2 on 23 Oct 1997

A PDF version of this primer, more suitable for printing, is available. Further information is here.

NOTE: POPLOG IS NOW FREE
In July 1999, version 15.53 of the Poplog system, including all its languages Pop-11, Prolog, Common Lisp, Standard ML, and most recently Scheme, became available free of charge with full system system sources. Since then there has been considerable further development work, especially on Linux x86 poplog, along with a project to port poplog to OSX on power pc, a port to HPUX, and there is an ongoing project to produce a new platform-independent version including graphics compatible with windows as well as linux and unix-based systems.

Further information is available at the Free Poplog site:

ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/freepoplog.html or

http://www.cs.bham.ac.uk/research/poplog/freepoplog.html

Distribution information in this HTML version of this primer is out of date. ISL no longer distribute Poplog or Pop-11 (though it was used to develop their Clementine system, which proved so successful that they were bought by SPSS specifically in order to obtain Clementain). For more information about the change see

http://www.cs.bham.ac.uk/research/poplog/poplog.info.html or

ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/poplog.info.html

Addition: 28 Feb 2002

Examples of displays produced by Pop-11's "RCLIB" Graphic Library can be found in http://www.cs.bham.ac.uk/research/poplog/figs/rclib/

• Contents
• INTRODUCTION TO SECOND EDITION (Jan 1996)
  • FOR NEW USERS: A TASTE OF POP-11
  • ACKNOWLEDGEMENTS
  • POPLOG INFORMATION AND FTP SITES
  • Sussex Web and FTP addresses
  • The Birmingham Poplog FTP directory
• PREFACE TO THE FIRST EDITION (Sept 1994)
  • Advantages of Pop-11
  • Pop-11 as a teaching language
  • Disadvantages of Pop-11
  • A brief history of Pop-11
  • The Poplog editor VED
  • Interactive programming
  • Declarative and procedural languages
  • The need for procedures
  • Monitors
  • TEACH files and the VED editor
  • The HELP command
  • The REF command
• CHAPTER.1: INTRODUCTION --- THE ROOMS EXAMPLE
  • POP-11 facilities illustrated in this chapter
  • The ROOMS DATABASE Example
  • Preliminary analysis
  • "Top down" and "Bottom up" design
  • Exercise on the ROOMS example
  • Searching for information in the "rooms" database
  • Finding several rooms
  • Exercises
  • Type-less higher order procedures
  • POP-11 : A MINIMAL MODEL
• CHAPTER.2: INTRODUCTION TO THE SYNTAX AND SEMANTICS OF POP-11
  • Internal semantics and external semantics
  • Expressions denote objects. Imperatives denote actions
  • Compile time vs run time processes
  • How a programming language is specified: virtual machines
  • Some Pop-11 data-types and their external forms
  • Some Pop-11 actions
  • Built in and user-defined procedures
  • Errors and error messages
  • Comments in Pop-11 programs
  • Pop-11 Expressions: some examples
  • Imperatives: some examples
  • Procedure definitions are initialised identifier declarations
  • Global and local procedure definitions
  • Procedure calls in Pop-11
  • Using infix operators
  • Procedures which produce results
  • Exercises
  • Introduction to printing in Pop-11
  • Conditionals and conditions
  • Predicates and recognizer procedures
  • Summary of syntactic roles in Pop-11 programs
  • Lexical analysis and the Pop-11 itemiser
  • Itemisation rules in Pop-11
  • Revision questions
  • Built in Pop-11 data types
  • Procedures associated with data-types
  • Data creation, memory management and the heap
  • List of Pop-11 Data-types
  • Further information on built in data types
  • Objectclass - An object oriented extension to Pop-11
  • Additional information needed to define Pop-11
  • The garbage collector
  • Exercises
• CHAPTER.3: PROCEDURES AND THE STACK
  • Procedures communicate via the stack
  • The DOT-notation for procedure calls
  • Assignment as a two stage operation
  • The stack and arithmetic expressions
  • Implicit uses of the stack
  • Example: implicit uses of the stack when running "perim"
  • Exercises on the stack
  • More examples of uses of the stack
  • "->" does not always represent an assignment
  • The print arrow "=>"
  • The pretty print arrow ==>
  • Using assignment to store something in a structure
  • Invoking the updater of a procedure
  • Other updaters: subscrv, subscrs
  • Using a numerical subscript to access or update a structure
  • updaters, the stack and "explode"
  • Defining updaters
  • Non-destructive assignment "->>"
  • Exercise
  • Multiple assignments
  • Some procedures which work on the stack
  • Clearing items from the stack (erase)
  • Removing unwanted items from the stack
  • Swapping items using the stack
  • Conditionals and the stack
• CHAPTER.4: PROCEDURES IN POP-11
  • Procedures as "first class objects"
  • Other languages able to manipulate procedures
  • Example: creating new procedures from old
  • Using "partial application" to create a closure
  • Using both partial application and procedure composition
  • Exercises on procedure creation and manipulation
  • Using non-procedures (e.g. lists, vectors) as procedures
  • Arrays are procedures in Pop-11
  • Properties as procedures
  • Exercise using properties for the rooms database
  • DEFINING PROCEDURES IN POP-11
  • Using "define <name> = ... enddefine"
  • Specifying the syntactic type of a procedure identifier
  • Executing (calling, running, applying) a procedure
  • Procedures with more than one output local
  • Output locals and the stack
  • Precedence and parentheses
  • Defining new infix procedures
  • Different types of procedures: normal, infix, macros, syntax
  • Some important constructs used in defining procedures
  • Loops: instructions to do something repeatedly
  • Using conditionals to jump out of, or re-start a loop.
  • Other syntactic constructs
  • Tracing procedures
  • Defining macros and syntax words to extend the language.
• CHAPTER.5: NUMERICAL AND LOGICAL FACILITIES IN POP-11
  • Mathematical knowledge presupposed
  • The machine representation of numbers in Poplog
  • Types of numbers in Pop-11
  • Forming numerical expressions
  • Additional facilities for printing numbers
  • Maximum and minimum integer sizes: pop_max_int, pop_min_int
  • The representation of floating point numbers: lib float_parameters
  • Basic arithmetical facilities
  • Arithmetical operators
  • Infix predicates on numbers
  • Recognizer predicates for number types
  • Coercing numbers from one type to another
  • Other arithmetic procedures
  • Illustrating popradians
  • Other global variables controlling arithmetical computations
  • Miscellaneous operations on integers, ratios, floats
  • Complex Specific Operations
  • random and oneof
  • Additional mathematical functions
  • Exercises
  • Testing for equality and inequality
  • Bitwise (Logical) integer operators
  • Iteration over numbers
  • Using external mathematical libraries
• CHAPTER.6: LIST PROCESSING IN POP-11
  • On knowing about lists
  • Why use lists?
  • Lists vs other representations
  • Lists in AI
  • Constructing lists in Pop-11
  • WARNING lists in procedures are not "constants"
  • Concatenating lists using <>
  • Merging lists using the double up-arrow
  • Lists are a derived data-type
  • Why use "hd" and "tl" instead of "front" and "back" ?
  • Diagrams showing static lists represented as pairs
  • Dynamic lists: generators and pdtolist
  • Some procedures for manipulating lists
  • Predicates on lists
  • Iterating on lists
  • Using for ... in ... do .... with lists
  • Iterating over two or more lists
  • Iteration vs Recursion
  • Exercises
  • More exercises on lists
  • Exercises on the meaning of the single and double up-arrows
• CHAPTER.7: THE POP-11 PATTERN MATCHER AND DATABASE
  • Using matches to define a procedure
  • Exercise
  • Use of the matcher to extract the contents of a list
  • The use of "?" variables
  • The matcher arrow "-->"
  • Findroom revisited
  • Setting a value ("?") vs Using a value ("^")
  • List pattern matching
  • Describing the shape of a list pattern
  • Using variables in a pattern specification
  • Matching a "segment" of a list
  • Retrieving details of the target list
  • Using a "restriction" to control or check the match
  • Summary of match notations
  • MATCHing on a corpus of lists - the DATABASE concept
  • Adding and removing database items
  • Using "it" to record what was removed
  • Finding items in the database
  • Using "it" to record what was matched
  • Retrieving values from within a matching ITEM
  • Using LOOKUP to extract information from the database
  • FOREACH: iterates over all items PRESENT matching a pattern
  • Checking a set of patterns against the database
  • Forevery: simultaneously satisfying a collection of patterns
  • LIB FMATCHES overcomes some limitations of the matcher
• CHAPTER.8 AN AI APPLICATION: A GENERAL PROBLEM SOLVER
  • Procedures to be supplied by users
  • The definition of solve_problem
  • Using solve_problem to solve a simple problem
  • Exercises
• CHAPTER.9 RECORDS, VECTORS AND OBJECTCLASS
  • Records
  • Defining new record types in Pop-11
  • Defining new vector types in Pop-11
  • OBJECTCLASS: an Object-Oriented extension to Pop-11
• APPENDIX
  • VMS DCL or UNIX shell commands in Pop-11
  • ADDITIONAL READING
• About this document ...

WARNING: some of the links below are now out of date and will not work. See also the following sources of information about Poplog and Pop-11.

(a) At The University of Birmingham (UK): http://www.cs.bham.ac.uk/research/poplog/poplog.info.html
or ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/poplog.info.html

(b) At The University of Sussex: Poplog Information at Sussex,

Pop-11 information at Sussex.

(c) At Reading University: the Reading Poplog site.

At the POPLOG.ORG web site