2005.02.10 - SLIDE 1IS146 - Spring 2005

Computation: Programmability

Prof. Marc Davis & Prof. Peter Lyman

UC Berkeley SIMS

Tuesday and Thursday 2:00 pm – 3:30 pm

Spring 2005http://www.sims.berkeley.edu/academics/courses/is146/s05/

IS146:

Foundations of New Media

2005.02.10 - SLIDE 2IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 3IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 4IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 5IS146 - Spring 2005

Algorithms and Programming

• Algorithm– A step-by-step description of a procedure to

achieve a desired result

• Programming– Primitives– Means of combination– Means of abstraction

2005.02.10 - SLIDE 6IS146 - Spring 2005

From Algorithms to Programs

• Algorithm– A step-by-step description of a procedure to

achieve a desired result– How can we walk a square?

• Walk forward• Turn• Walk forward• Turn• Walk forward• Turn• Walk forward

2005.02.10 - SLIDE 7IS146 - Spring 2005

LOGO Square Example

• to square– forward 50– right 90– forward 50– right 90– forward 50– right 90– forward 50– end

2005.02.10 - SLIDE 8IS146 - Spring 2005

LOGO Square Example

• to square– params [size]– forward :size– right 90– forward :size– right 90– forward :size– right 90– forward :size– end

2005.02.10 - SLIDE 9IS146 - Spring 2005

LOGO Window Example

• to window– params [size]– square :size– square :size– square :size– square :size– end

2005.02.10 - SLIDE 10IS146 - Spring 2005

LOGO Window Example

• to window– params [size]– repeat 4 [square :size]– end

2005.02.10 - SLIDE 11IS146 - Spring 2005

LOGO Window Example

• to window– params [size]– make squaresize (:size/2)– repeat 4 [square :squaresize]– end

2005.02.10 - SLIDE 12IS146 - Spring 2005

LOGO Square Example

• to square– params [size]– forward :size– right 90– forward :size– right 90– forward :size– right 90– forward :size– end

2005.02.10 - SLIDE 13IS146 - Spring 2005

LOGO Square Example

• to square– params [size]– forward :size– right 90– forward :size– right 90– forward :size– right 90– forward :size– end

2005.02.10 - SLIDE 14IS146 - Spring 2005

LOGO Square Example

• to square– params [size]– forward :size– right 90– forward :size– right 90– forward :size– right 90– forward :size– end

2005.02.10 - SLIDE 15IS146 - Spring 2005

LOGO Square Example

• to square– params [size]– forward :size– right 90– forward :size– right 90– forward :size– right 90– forward :size– end

2005.02.10 - SLIDE 16IS146 - Spring 2005

LOGO Polygon Example

• to poly – params [sides length]

– repeat :sides [forward :length right (360/:sides)]

– end

2005.02.10 - SLIDE 17IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 18IS146 - Spring 2005

Programming Concepts

• Basic programming constructs– Parameters– Loops– Procedural abstraction– Subroutines– Conditionals

2005.02.10 - SLIDE 19IS146 - Spring 2005

Making a “C”

• to c– params [height]– make halfheight :height/2– left 90– forward :height– right 90– forward :halfheight – right 180– forward :halfheight– left 90– forward :height – left 90– forward :halfheight– end

2005.02.10 - SLIDE 20IS146 - Spring 2005

Making an “A”

• to a– params [height]– make halfheight :height/2– left 90– forward :height– right 90– forward :halfheight – right 90– forward :halfheight – right 90– forward :halfheight– right 180– forward :halfheight– right 90– forward :halfheight– left 90– end

2005.02.10 - SLIDE 21IS146 - Spring 2005

Making an “M”

• to m– params [height]– make diagonal (:height/2)*7/5– left 90– forward :height– right 135– forward :diagonal – left 90– forward :diagonal – right 135– forward :height– left 90– end

2005.02.10 - SLIDE 22IS146 - Spring 2005

Making an “R”

• to r– params [height]– make halfheight :height/2– make diagonal :halfheight*7/5– left 90– forward :height– right 90– forward :halfheight – right 90– forward :halfheight – right 90– forward :halfheight – left 135– forward :diagonal– left 45– end

2005.02.10 - SLIDE 23IS146 - Spring 2005

Making a “space”

• to space– params [length]– penup– forward :length– pendown– end

2005.02.10 - SLIDE 24IS146 - Spring 2005

Making “MARC”

• to marc– params [height kerning]– m :height– space :kerning– a :height– space :kerning– r :height– space :kerning– c :height– end

2005.02.10 - SLIDE 25IS146 - Spring 2005

Making “hopback”

• to hopback– params [length]– penup – back :length– pendown– end

2005.02.10 - SLIDE 26IS146 - Spring 2005

Making a Circle of “MARC”

• to marccircle– params [letterheight letterkerning]– make marcnamewidth

((:letterheight*5/2)+(3*:letterkerning))– repeat 360/:letterheight – [marc :letterheight :letterkerning– hopback :marcnamewidth – right :letterheight– ]– end

2005.02.10 - SLIDE 27IS146 - Spring 2005

Conditionally Making “MARC” Circles• to marccirclecond

– params [letterheight letterkerning circletightness]– make marcnamewidth

((:letterheight*5/2)+(3*:letterkerning))– ifelse (:circletightness=0)– [make rotation :letterheight] – [make rotation :letterkerning]– repeat 360/:rotation [marc :letterheight :letterkerning– hopback :marcnamewidth – right :rotation– ]– end

2005.02.10 - SLIDE 28IS146 - Spring 2005

Making a Square of “MARC”

• to marcsquare– params [letterheight letterkerning]– make marcnamewidth ((:letterheight*5/2)+(3*:letterkerning))– repeat :marcnamewidth/:letterheight– [marc :letterheight :letterkerning– hopback :marcnamewidth– left 90– penup– forward :letterheight– right 90– pendown– ]– end

2005.02.10 - SLIDE 29IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 30IS146 - Spring 2005

Andrea Brown on Hillis

• Hillis says that “Learning a programming language is not nearly as difficult as learning a natural human language.” Do you think that if humans had difficulty comprehending natural language that their ability to learn programming language would be affected?

2005.02.10 - SLIDE 31IS146 - Spring 2005

Andrea Brown on Hillis

• Hillis mentions that the “most successful computers … are generally regarded by computer designers as having poorly designed instruction sets.” Why is that? If computers are meant to mimic the complexity of humans why don’t “successful computers” have elaborate instruction sets?

2005.02.10 - SLIDE 32IS146 - Spring 2005

Lecture Overview

• Assignment Check In– Assignment 3: Documenting Artifact Usage

• Review of Last Time– Computation: Programming Concepts

• Today– Computation: Programmability

• Preview of Next Time– Computational Media

2005.02.10 - SLIDE 33IS146 - Spring 2005

Readings for Next Time

• Walter Benjamin. The Work of Art in the Age of Mechanical Reproduction. In: Illuminations, edited by Walter Benjamin, New York: Schocken Books, 1985, p. 217-251. – Discussion Questions

• Steven Lybeck

• Lev Manovich. The Language of New Media, Cambridge, Massachusetts: The MIT Press, 2001, p.18-61. – Discussion Questions

• Mark Martell