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

• 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 ...

See also the following sources of information about Poplog and Pop-11.

(a) at Birmingham (UK): ftp://ftp.cs.bham.ac.uk/pub/dist/poplog/

and

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

(b) at Sussex University: Poplog Information at Sussex.

Pop-11 information at Sussex.

(c) at Reading University Reading University

(d) At Integral Solutions Ltd, the main Poplog distributors http://www.isl.co.uk/

and a brief introductory overview of Pop-11 http://www.isl.co.uk/pop11int.html