Organization of the New Course on Complier Construction in Novi Sad

1
Organization of the New Course on Complier
Construction in Novi Sad

• Vladimir Kurbalija, Mirjana Ivanovic
• Department of Mathematics and Informatics
• University of Novi Sad
• Serbia

2
Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

3
CC Course in Novi Sad

• One of core software courses at Computer Science
  directions
• 7th semester CC1 (obligatory), 8th semester CC2
  (elective), for students of
• Computer Science,
• Business Computer Science,
• Teaching of Computer Science

4
Previous CC Course

• Practical approach
• Development of Pascal- compiler
• Subset of Pascal language
• data types boolean and integer standard types,
  arrays and fixed records as structured types
• basic statements assignment statement, procedure
  call, if and while statements
• Standard input/output (read and write)
  procedures, user defined procedures including
  recursion.
• The implementation
• recursive-descent manner for syntax analysis
• code generation for abstract P machine

5
Previous CC Course - Exercises

• Students repeat and train practical skills gained
  during lectures
• Several independent tasks small grammars
• Implementation language is Modula-2
• Compiler generator Coco/R
• Tasks
• Lexical and syntax analysis and some parts of
  semantic analysis using Coco/R
• Hand written parsers (LA SA)
• Hand written parsers with semantic analysis and
  rarely with code generation or interpretation
• Some algorithms on grammars (memory organisation,
  checking consistency, computing first and follow
  sets)

6
Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

7
Current CC Course

• More theoretical approach on lectures
• Course goes through all phases of a compiler
  writing
• Shows the theoretical concepts underlying each
  phase as well as how to implement it efficiently
• Examples MicroJava compiler in Java, target
  language subset of Java byte code
• Goals of the course
• acquire the practical skills to write a simple
  compiler for an imperative programming language
• understand the concepts of scanning, parsing,
  name management in nested scopes, and code
  generation.
• learn to transfer the skills also to general
  software engineering tasks

8
Current CC Course

• Structure of Lectures
• Overview (1 week)
• Lexical Analysis (1 week)
• Syntax Analysis (2 weeks) --- TEST
• Attribute Grammars (1 week)
• Symbol Table (2 weeks)
• Code Generation (3 weeks) --- TEST
• BU Parsing (2 weeks)
• Compiler Generators (1 week) --- TEST

9
Current CC Course Exercises

• Students should acquire practical skills in
  compiler writing
• One (big) project divided in smaller subtasks
• Students should write a small compiler for a
  Java-like language - MicroJava
• The implementation language is also Java

10
Current CC Course Exercises

• Study material
• Teaching material (slides)
• Description of the project
• Specification of MicroJava language (tokens,
  language grammar, semantic and context
  constraints)
• Specification of MicroJava virtual machine
  (similar but simpler than Java VM) Memory
  layout and Instruction set
• Specification of object file format

11
Current CC Course Exercises

• The project consists of three levels
• Level 1 implementation of a scanner and a
  parser for the language MicroJava, error handling
  3 TASKS
• Level 2 - deals with symbol table handling and
  type checking 1 TASK
• Level 3 - deals with code generation for the
  MicroJava 1 TASK

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Current CC Course Exercises

• Level 1 Task 1
• Lexical analysis
• Implementation of a scanner for MicroJava
• Scanner should skip blanks, end of line
  characters, tabulator characters and comments
• Types of errors
• The occurrence of an invalid character (e.g., )
• A missing quote at the end of the character
  constant ('x)
• Integer constants that are too large
• Some algorithms for token recognition are
  explained
• Given material
• A frameworks of Scanner.java and Token.java
  classes
• Test examples

13
Current CC Course Exercises

• Level 1 Task 2
• Syntax analysis
• Implementation of a recursive descent parser for
  MicroJava
• Without error handling stop on first error
• The algorithm for recursive descent parser is
  explained
• Given material
• A complete grammar of MicroJava
• A framework of Parser.java class
• Test examples Programs in MicroJava

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Current CC Course Exercises

• Level 1 Task 3
• Error handling
• Modification of the parser and error() method
• 2 kinds of algorithms
• method with special anchors
• method with general anchors
• These 2 algorithms are explained in detail
• Given material
• Set of anchors

15
Current CC Course Exercises

• Level 2
• Semantic analysis
• Symbol table handling and type checking
• Semantic analyzer should check
• Type compatibility
• Predeclared names
• Scope
• Students should implement Obj.java, Struct.java,
  Scope.java and Tab.java classes and modify parser
• The functionality of these classes is explained
• Given material
• Frameworks of Obj.java, Struct.java, Scope.java
  and Tab.java classes
• Context conditions in the grammar
• Test examples

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Current CC Course Exercises

• Level 3
• Code generation
• Generate code for the MicroJava Virtual Machine
  (stack machine)
• MicroJava Virtual Machine and its instruction set
  (57 instructions) are described in detail
• Students should implement Code.java, Item.java
  and Label.java classes and modify parser
• Given material
• Full implementation of MicroJava VM
• Decoder.java class for viewing generated code
• Frameworks of Code.java, Item.java and Label.java
  classes
• Test examples

17
Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

18
Assessment by students in Novi Sad

• Questionnaire - students opinion
• 52 students, 34 filled questionnaire
• 26 questions
• For every question grade 1 to 5
• Meaning of answers
• 1 I do not agree at all
• 5 I agree completely

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Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

20
Questionnaire - General

• The organization of the course was good
• 1 2 3 4 5
• 1 1 2 14 16 AVERAGE 4.26
• The possibility of passing the exam using
  colloquiums and tests is useful
• 1 2 3 4 5
• 2 2 2 9 19 AVERAGE 4.21
• Type and difficulty of tasks are correct
• 1 2 3 4 5
• 1 2 14 12 5 AVERAGE 3.53
• The amount of material is good
• 1 2 3 4 5
• 0 0 7 12 15 AVERAGE 4.24

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Questionnaire - General

• Lectures and exercises were good synchronized
• 1 2 3 4 5
• 0 0 8 9 17 AVERAGE 4.26
• Teaching material is good
• 1 2 3 4 5
• 1 4 15 9 5 AVERAGE 3.38
• The quality of course is good
• 1 2 3 4 5
• 0 0 8 18 8 AVERAGE 4.00
• Course is useful
• 1 2 3 4 5
• 0 2 7 13 12 AVERAGE 4.03

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Questionnaire - Lectures

• Lectures were good prepared
• 1 2 3 4 5
• 0 1 2 12 19 AVERAGE 4.44
• Teaching style is good
• 1 2 3 4 5
• 1 0 4 14 15 AVERAGE 4.24
• I have learned enough during lectures
• 1 2 3 4 5
• 1 2 19 10 2 AVERAGE 3.29
• Lecturer was willing to give additional answers
• 1 2 3 4 5
• 0 0 3 9 21 AVERAGE 4.55
• The speed of presentation was adequate
• 1 2 3 4 5
• 0 3 9 12 10 AVERAGE 3.85
• Generally, I am satisfied with the lectures
• 1 2 3 4 5
• 0 1 6 16 10 AVERAGE 4.06

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Questionnaire Exercises

• Exercises were good prepared
• 1 2 3 4 5
• 0 0 4 8 22 AVERAGE 4.53
• Teaching style of assistant is good
• 1 2 3 4 5
• 0 1 3 8 22 AVERAGE 4.50
• Assistant was willing to give additional answers
• 1 2 3 4 5
• 0 0 0 5 29 AVERAGE 4.85
• I have learned enough during exercises
• 1 2 3 4 5
• 0 0 9 13 12 AVERAGE 4.09
• The speed of presentation was adequate
• 1 2 3 4 5
• 0 0 5 14 15 AVERAGE 4.29
• The difficulty of tasks was adequate
• 1 2 3 4 5
• 0 1 10 11 11 AVERAGE 3.97
• Generally, I am satisfied with the exercises

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Questionnaire - Effort

• How many times did you miss lectures?
• lt3 3-7 gt7
• 24 9 1
• How many times did you miss exercises?
• lt3 3-7 gt7
• 23 10 1
• Did you need additional consultations?
• YES NO
• 7 27
• By your own opinion, how many hours per week
  should be spent preparing for this course?
• AVERAGE 5.66
• How many hours per week did you spent preparing
  for this course?
• AVERAGE 4.05

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Exam results

• 52 students, 41 passed the exam
• 38 in January
• 1 in April
• 2 in June
• Grade distribution (6-10)
• 6 7 students
• 7 14 students
• 8 16 students
• 9 2 students (oral exam)
• 10 1 student (oral exam)

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Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

27
JCCC - Material

• Novi Sad
• CC1 obligatory, CC2 elective
• CC1 use Teaching material of prof. Mössenböck,
  Linz
• CC2
• More theoretical, Automata theory, Formal
  languages theory
• Other parsing methods (LR, LALR)
• Detailed presentation of code generation
• Different techniques of code optimization
• Exercises and practical work Real-world (more
  serious project)

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JCCC - Material

• Belgrad
• CC1 obligatory, CC2 elective
• CC1
• Partially use teaching material of prof.
  Mössenböck, Linz,
• more theory,
• extended version of microJava with object
  inheritance
• CC2
• Similar to Novi Sad
• .doc file

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JCCC - Material

• Possibilities to prepare common material
• Belgrad is more ambitious then Novi Sad
• Dragan want to prepare his own material and
  slides
• But he has not time and appropriate motivation
  for that
• Novi Sad
• Will use Linz material, completely for CC1
• We are willing to prepare presentations for CC2
  topics
• But also seems that we have not appropriate
  motivation
• Open Question Writing book
• We have a lot of draft materials
• Motivation? project, publishing,
• Problem CC2 is elective, we do not expect
  students

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Agenda

• Previous CC Course
• Current CC Course
• Assessment by students in Novi Sad
• Questionnaire and Exam results
• JCCC Material
• Conclusion

31
Conclusion Novi Sad Approach

• Advantages of new course
• Concepts of compiler construction are shown on
  formal way
• Modern and object-oriented language is used (Java
  and Java byte code)
• Most of students autonomously write important
  parts of compiler
• Better students are able to write (almost) whole
  compiler
• The exam can be passed during the semester
  continual assessment
• Some students complain that there is not enough
  literature on Serbian (enough motivation for
  book?)

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Thank you for your attention