COSC 3127 Programming Languages Dave Goforth dgoforth@cs.laurentian.ca FA377

COSC 3127Programming Languages

Dave Goforth

dgoforth@cs.laurentian.ca

FA377

Topics of the course

• Understand current “state-of-the-art”

• Describe languages formally

• Understand implementation concepts

• Understand design concepts

With what purpose?

• More skillful use of languages

• Evaluation of languages

• Learning to learn languages

• New languages

Organization

• Lectures (notes on my website)

• Textbook (Sebesta, 8/e)

• Reference materials on Sebesta website

Evaluation

5 assignments 20%

1 project 20%

1 midterm exam 20%

1 final exam 40%

Why programming languages?

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if (n<0) x := x+1;else x := 2x;n++;

Computer

processing

Why programming languages?

Human

effort1949

2007

???

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Computer

processing

Why programming languages?

Human

effort

1949

Computer

processing

Why programming languages?

Human

effort

2007

Language design

Question 1

Domain specific OR General purpose?

Maple

Excel

Photoshop

awk

JAVA

C,C++,C#

Pascal

libraries

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Language design - constraints

Humans:

Creative

Intuitive

Forgetful

Prone to error

Computers:

Precise

Logical

von Neumann architecture

von Neumann Architecture(Sebesta)

Execution of Machine Code(Sebesta)

• Fetch-execute-cycle

(on a von Neumann architecture)

initialize the program counter

repeat forever

fetch the instruction pointed by the counter

increment the counter

decode the instruction

execute the instruction

end repeat

Move data

I/O data

Operate on data (test, compute)

Reset program counter

Instruction setMemory codes

Execution of Machine Code(Sebesta)

• Fetch-execute-cycle

(on a von Neumann architecture)

initialize the program counter

repeat forever

fetch the instruction pointed by the counter

increment the counter

decode the instruction

execute the instruction

end repeat

Instruction setMove dataOperate on dataI/O dataReset program counter

Memory codes

Primitive data types

arrays

records

objects

Reset program counter

if

switch

counted

recursion

branch

goto

selection repetition

logicalsubprogram

Language Evolution from machine level

Instruction set

Sample slide page

• Text

• Text

• Text