Practical Issues, Odds and Ends

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. • <Ch>(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 1 100 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 • declareclass Registry …endclass SubRegistry from Registry…endX=[a b c d]proc{Q U} … endproc{P A B} {Q X}endY=mySave(a:SubRegistry b:[e f g] c:P}{Pickle.save Y ‘xxx’} %%% everything saved directly or %%% indirectly • declareX={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