Turtle Graphics implementation using a graphical dataflow programming approach.

202 Pages·1.8 MB·en_US

by  Lovejoy, Robert Steven.;Wu, C. Thomas.;Erickson, David A.

DUDLEY > uBRARY
NAVAL POSTGRADUATE SCHOOL
MONTEREY CA
93943-5101

Approved for public release; distribution is unlimited
Turtle Graphics Implementation Usinga
GraphicalDataflow ProgrammingApproach
by
RobertSteven Lovejoy
Lieutenant, UnitedStates Navy
B.S., Bradley University, 1983
Submitted in partial fulfillment ofthe
requirements for the degree of
MASTER OF COMPUTER SCIENCE
from the
NAVAL POSTGRADUATE SCHOOL
September, 1992
UlM^Lv/\3,Mrlcl;
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SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION/AVAILABILITYOF REPORT
Approved for public release;
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PERFORMING ORGANIZATION REPORT KIUMBER(s) 5. MONITORING ORGANIZATION REPORT NUMBER(s)
NAME OF Performing ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OPMONITORINGORGANIZATION
omputer Science Dept. (ifapplicable) Naval Postgraduate School
aval Postgraduate School 37
ADDRESS (City, State, andZIPCode) 7b.ADDRESS (City, State, andZIPCode)
onterey, CA 93943-5000 Monterey, CA 93943-5000
NAME OF FUNDING/SPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENTINSTRUMENTIDENTIFICATION NUMBER
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ADDRESS (City, State, andZIPCode) 10. SOURCE OF FUNDING NUMBERS
PROGRAM PROJECT TASK WORKUNI
ELEMENTNO. NO. NO. ACCESSIO
TITLE (IncludeSecurityClassification)
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JRTLE GRAPHICS IMPLEMENTATION USING A GRAPHICALDATAFLOW PROGRAMMING APPROACH
PERSONALAUTHOR(S)
.
Lovejoy, Robert Steven
a. TYPE OFREPORT 13b. TIME COVERED 14. DATEOF REPORT(Year, Month, Day) 15. PAGE COUNT
aster sThesis FROM to: 1992, September 194
SUPPLEMENTARY NOTATION
The views expressed in this thesis are those ofthe authorand do not reflect the offic
policy or position ofthe Department ofDefense or the United States Government
COSATI CODES 18. SUBJECTTERMS(Continueonreverseifnecessaryandidentifybyblocknumber)
OBJECT ORIENTED PROGRAMMING, TURTLE GRAPHICS,
FIELD GROUP SUB-GROUP VISUAL DATAFLOW PROGRAMMING
ABSTRACT(Continueonreverseifnecessaryandidentifybyblocknumber)
This thesis expands the concepts of object-oriented programming to implement a visual dataflow programi
nguage. Themain thrustofthisresearchis to developafunctional prototypelanguage,based upon theTurtleGr
LOGO
5 tool provided by programming language, forchildren to develop both theirproblem solving skills, as
their general programming skills.
The language developed for this thesis was implemented in the object-oriented, dataflow programming lang
ograph. The dataflow paradigm was emulated in order to provide a more intuitive, easy to learn programming
ronment for children to use. Additionally, Prograph was chosen because it provides the necessary base class,
sily implement an interactive user interface, and it provides the necessary primitive operations for all grail
awing routines.
This thesis demonstrates a prototype for a potential visual programming language that can be used at all levej
ucation to teach problem solving, higher-order thinking skills, mathematical concepts, and the fundamental
mputer science.
disTribuTiOn/AvaIlaBIlITYOF ABSTRACT 21 ABSTRACTSECURITY CLASSIFICATION
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ABSTRACT
This thesis expands the concepts ofobject-oriented programming to implement
a visual dataflow programming language. The main thrust of this research is to
develop a functional prototype language, based upon the Turtle Graphics tool
LOGO
provided by programming language, for children to develop both their
problem solving skills as well as their general programming skills.
The language developed for this thesis was implemented in the object-oriented,
dataflow programming language Prograph. The dataflow paradigmwas emulated in
order to provide a more intuitive, easy to learn programming environment for
children to use. Additionally, Prograph was chosen because it provides the
necessary base classes to easily implement an interactive user interface and it
provides the necessary primitive operations for all graphics drawing routines
This thesis demonstrates a prototype for a potential visual programming
language thatcan be used atall levels ofeducation to teach problem solving, higher-
order thinking skills, mathematical concepts, and the fundamentals of computer
science.
Ul
$335$ Table Of Contents
CI
INTRODUCTION
I. 1
SURVEY OF THE LITERATURE
II. 3
A. OBJECT-ORIENTED PROGRAMMING 3
1. Classes/Objects and Related Variables and Methods 4
2. Inheritance 5
3. Encapsulation 7
4. Polymorphism... 8
B. TURTLE GRAPHICS PROGRAMMING LANGUAGE 9
1. Turtle Graphics Origin 9
2. Overall Educational Benefit 10
a. Case Studies 10
b. Problem Solving Skills 11
c. Specific Curriculum Benefits 12
3. The Language 13
a. Turtle Space 13
b. Making Shapes 14
c. Making Procedures 14
d. Generalizing Procedures 15
C. PROGRAPH: AVisual Dataflow Program Style 16
1. Visual Systems-Iconic Based 17
a. Classes 17
b. Attributes 18
c. Methods 19
2. Visual Systems-Dataflow Based 20
a. Message Passing/Invoking a Method 22
b. Control Structures 23
III. DATAFLOW TURTLE GRAPHICS 28
A. LANGUAGE EVOLUTION 28
B. WHY VISUAL PROGRAMMING 29
IV
DUDLEY KNOX LIBRARY
NAV.AL POSTGRADUATE SCHOOL
^^..S*...™<&™
1. Dual Brain Theory
2. A Need For a New Programming Style 30
WHY DATAFLOW PROGRAMMING
C. 30
1. Executable versus Non-Executable Diagrams 31
2. Dataflow Functionality 31
D. ICONIC LANGUAGES 32
1 Iconic Guidelines 32
.
E. TURTLE GRAPHICS DESIGN AND IMPLEMENTATION 33
1. Developing Turtle Class/Objects and Methods 34
a. Class Hierarchy 34
b. Turtle/pTurtle Class Definitions 35
c. User Interface Design and Implementation: First Phase 36
2. Integration ofTurtle Code and Dataflow Programming Code 39
a. Class Hierarchy 39
b. DFObject and Descendents 40
c. User Interface Design and Implementation: Second Phase 41
d. Program Objects: Icon-Description and Functionality 44
IV. PROBLEM SOLVING WITH DATAFLOW TURTLE GRAPHICS 48
A. GENERALDISCUSSION 48
B. PROBLEM STATEMENT 48
C. DEVELOPING A SOLUTION 48
1. DFTG's Object-Oriented Approach to Problem Solving 48
2. "Man-Project" Problem Reduction 49
a. Create Turtles 49
b. Creating the Head 49
c. Create a Face 50
d. Create a body 50
e. Create a bowtie 51
f. Create legs 53
.
g. Create arms 54
h. Final Code Encapsulation 54
SUMMARY, CONCLUSIONS, & SUGGESTIONS FOR FUTURE
V.
RESEARCH
58
SUMMARY
A. 58
CONCLUSIONS
B. 59
SUGGESTIONS FOR FUTURE RESEARCH
C. 59
1 Completion of"user-defined Turtle command" functionality 60
2. Completion of"user-help" functionality 60
3. Expand language control constructs 60
4. Fully implement Error detection/correction capabilities 60
5. Incorporate a programming pallet ofavailable commands 61
6. Implement additional Turtle functionality 61
7. Perform statistical studies ofuser effectiveness 61
APPENDIXA - USER COMMAND/METHOD DEFINITIONS 62
APPENDIX B - NEW TURTLE GRAPHICS - SOURCE CODE 66
LIST OF REFERENCES 180
BIBLIOGRAPHY
182
INITIAL DISTRIBUTION LIST 183
VI