1 Practical Issues, Odds and Ends Per Brand

2 Base Environment - Reference Manual Table of Contents 1 Introduction 2 Type Structure and Description Format 3 Values 4 Numbers 5 Literals 6 Records, Tuples, and Lists 7 Text 8 Procedures and Cells 9 Chunks 10 Control 11 Infix Notations 12 Miscellaneous Bibliography Index

3 Base Environment Contains a short description of all language entities (types) Contains a short description of fundamental operations on language entities Contains a number of useful abstractions on language entities Part 6 - Records, tuples, lists –Many useful list/record abstractions Part 10 - Control –What you can do with 1st class threads Part 4 - Numbers –Arithmetical operations Part 9- Chunks –Also arrays, dictionaries

4 Chunks A chunk is similar to a record except that:.The label of a chunk is an Oz-name..There is no Arity operation available on chunks. This means one can hide certain components of a chunk if the feature of the component is an Oz-name that is visible only (by lexical scoping) to user-defined operations on the chunk.

5 Chunks II A chunk is created by: {NewChunk Record ?Chunk}. This creates a chunk with the same arguments as the record, but having a unique label. local X in {Browse X={NewChunk f(c:3 a:1 b:2)}} {Browse X.c} end This will display the following. – (a:1 b:2 c:3) 3

6 Chunks-III Chunks and cells are primitive in Oz. –Objects, classes etc. can be defined in terms of them –Interesting as the smaller the kernel of a programming system is predictability good properties for program analysis, etc. For our purposes we will briefly consider arrays and dictionaries- abstractions that can be built on top of chunks

7 Arrays Arr={NewArray nil} –creates an array of 100 elements indexed by 1 to 100 that are initialized to nil {Array.put Arr 1 a} or Arr.1:=a X={Array.get Arr 1}or X=Arr.1 R={Array.toRecord +Label +Array} –creates a record(tuple) that is a stateless copy of the array –(you may find this useful for distribution)

8 Dictionaries Dict={NewDict} –creates a dictionary and association between Keys and Entries –Keys are atoms, integers, or names –Entries can be anything {Dictionary.put Dict Key WhatEver} or Dict.Key:=WhatEver X={Dictionary.get Dict Key}or X=Dict.Key X={Dictionary.condGet Dict Key Default} –equivalent to Dictionary.get if there is a entry in the Dictionary for that key- otherwise X=Default X={Dictionary.keys Dict} –returns a list of current keys X={Dictionary.entries Dict} –returns a list of current entries of form Key#Entry R={Dictionary.toRecord +Label +Dict} –creates a record(tuple) that is a stateless copy of the dictionary –(you may find this useful for distribution)

9 System Modules Part I: Application Programming –1 Application Support: Application –2 Module Managers: Module need to know this Part II: Constraint Programming not needed for this course Part III: Distributed Programming will be considered later Part IV: Open Programming –17 Files, Sockets, and Pipes: Open –18 Operating System Support: OS These are just the OZ interface to OS and File system services Read on need

10 More System Modules Part V: System Programming –19 Persistent Values: Pickle –20 Emulator Properties: Property read for overview - read on need –21 Error Formatting: Error –22 System Error Formatters: ErrorFormatters –23 Memory Management: Finalize –24 Miscelleanous System Support: System read for overview - details on need Part VI: Window Programming – 25 The Module Tk – 26 Graphical Tools: TkTools deals with graphics you won’t need this because we have done it for you Part VII: Miscellaneous –27 Support Classes for Objects: ObjectSupport

11 Pickle A pickle is a file that represents stateless Oz graphs (transitive closure) Any stateless value can be pickled - i.e. stored on file and retrieved from file Stateless includes numbers, atoms, strings, procedures, classes –stateless includes both data and code Stateless does not include cells, objects, single-assignment variables The Mozart system consists of two parts –the engine (a virtual machine) –a number of Oz modules –all the Oz modules exist in pickled form - when you start Oz the Oz- base environment modules will be loaded eagerly and the other modules upon need (access) The user can pickle and unpickle himself

12 Pickles-cont’d declare class Registry … end class SubRegistry from Registry … end X=[a b c d] proc{Q U} … end proc{P A B} {Q X} end Y=mySave(a:SubRegistry b:[e f g] c:P} {Pickle.save Y ‘xxx’} %% everything saved directly or %% indirectly declare X={Pickle.load ‘xxx’} %% get everything

13 Resources Resources are references from Oz to system resources –files, file system –windows, standard input/output Resources may not be pickled - reasons –Security –Unclear scoping - dynamic or static dynamic - resources of loader static - resources of saver Instead pickle functors that are dynamically linked to resources upon loading

14 Stand-alone -.ozf Standalone application, file p1.oz ( ozc -c p1.oz ) results in the file p1.ozf functor import System Application define {System.show 'hello world'} {Application.exit 0} end ozengine p1.ozf