How to Design Programs: Difference between revisions

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{{Short description|Computer programming textbook by Matthias Felleisen and colleagues}}

[[Image:Htdp.jpg|164px|thumb|right|Front cover]]

{{Use mdy dates|date=July 2018}}

{{Infobox book

| name = How to Design Programs

| image = How to Design Programs (front cover).jpg

| caption =

| author = [[Matthias Felleisen]], [[Robert Bruce Findler]], [[Matthew Flatt]], [[Shriram Krishnamurthi]]

| cover_artist =

| country = United States

| subject = [[Computer programming]]

| genre = [[Textbook]]

| publisher = [[MIT Press]]

| pub_date = February 12, 2001

| media_type = print

| pages = 720

| isbn = 0-262-06218-6

| oclc =

| dewey =

| congress = QA76.6 .H697 2001

| website = {{URL|htdp.org}}

}}

'''''How to Design Programs''''' ('''''HtDP''''') is a textbook by [[Matthias Felleisen]], [[Robert Bruce Findler]], [[Matthew Flatt]], and [[Shriram Krishnamurthi]] on the systematic design of [[computer program]]s. [[MIT Press]] published the first edition in 2001, and the second edition in 2018, which is freely available online and in print. The book introduces the concept of a ''design recipe'', a six-step process for creating programs from a problem statement. While the book was originally used along with the education project ''TeachScheme!'' (renamed [[ProgramByDesign]]), it has been adopted at many colleges and universities for teaching program design principles.

'''''How to Design Programs''''' (HTDP) is a textbook from MIT Press on the

systematic design of [[computer programs]]. The book introduces the concept of a

''design recipe'', a six-step process for creating programs from the problem

statement. The process starts with a careful analysis of the problem statement

with the goal of extracting a rigorous description of the kinds of [[data]] that

the desired program consumes and produces. The structure of these data

descriptions determines the organization of the program.

According to HtDP, the design process starts with a careful analysis of a problem statement with the goal of extracting a rigorous description of the kinds of [[data]] that the desired program consumes and produces. The structure of these data descriptions determines the organization of the program.

The book therefore carefully introduces more and more complex kinds of data,

which sets it apart from every other introductory programming book. It starts

from ''atomic'' forms of data and then progresses to ''compound'' forms of

data, including data that can be arbitrarily large. For each kind of data

definition, the book explains how to organize the program in principle, thus

enabling a programmer who encounters a new form of data to still construct a

program systematically.

Then, the book carefully introduces data forms of progressively growing complexity. It starts with data of ''atomic'' forms and then progresses to ''compound'' forms, including data that can be arbitrarily large. For each kind of data definition, the book explains how to organize the program in principle, thus enabling a programmer who encounters a new form of data to still construct a program systematically.

Like [[SICP]], HTDP relies on a variant of the [[Scheme programming language]]. Indeed, it comes with its own programming environment, dubbed [[DrScheme]], which provides a series of programming language. The first language supports only functions, atomic data and simple structures. Each language adds expressive power to the previous one. With the exception of the largest teaching language, all languages for HtDP are [[functional programming languages]].

Like ''[[SICPStructure and Interpretation of Computer Programs]]'' (SICP), HTDPHtDP relies on a variant of the programming language [[Scheme (programming language)|Scheme]]. Indeed, it comesIt withincludes its own programming [[integrated development environment]] (IDE), dubbednamed [[DrSchemeDrRacket]], which provides a series of programming languagelanguages. The first language supports only functions, atomic data, and simple structures. Each language adds expressive power to the previousprior one. WithExcept the exception offor the largest teaching language, all languages for HtDP are [[functional programming languages]] languages.

HTDP is available [http://www.htdp.org on-line].

==Pedagogical basis==

[[Category:Textbooks]]

In the 2004 paper, The Structure and Interpretation of the Computer Science Curriculum,<ref>{{Citation

|url=http://www.ccs.neu.edu/scheme/pubs/jfp2004-fffk.pdf

|title=The Structure and Interpretation of the Computer Science Curriculum. Journal of Functional Programming, Volume 14, Issue 4 (July 2004) Pages: 365 - 378

|year=2004

|publisher=NEU

|url-status=live

|archive-url=https://web.archive.org/web/20080511171056/http://www.ccs.neu.edu/scheme/pubs/jfp2004-fffk.pdf

|archive-date=May 11, 2008

}} a paper in which the authors compare and contrast HtDP with SICP.</ref> the same authors compared and contrasted the pedagogical focus of ''How to Design Programs'' (HtDP) with that of ''[[Structure and Interpretation of Computer Programs]]'' (SICP). In the 14-page paper, the authors distinguish the pedagogic focus of HtDP from that of SICP, and show how HtDP was designed as a textbook to address some problems that some students and teachers had with SICP.

The paper introduces the pedagogical landscape surrounding the publication of SICP. The paper starts with a history and critique of SICP, followed by a description of the goal of the [[computing]] curriculum. It then describes the principles of teaching behind HtDP; in particular, the difference between implicit vs. explicit teaching of design principles. It then continues on to describe the role of [[Scheme (programming language)|Scheme]] and the importance of an ideal [[Computer programming|programming]] environment, and concludes with an extensive evaluation of content and student/faculty reaction to experience with SICP vs. HtDP.

One of the major focuses of the paper is the emphasis on the difference in required [[___domain knowledge]] between SICP and HtDP. A chart in the paper compares major exercises in SICP and HtDP, and the related text describes how the exercises in the former require considerably more sophisticated ___domain knowledge than those of HtDP. The paper continues on to explain why this difference in required ___domain knowledge has resulted in certain students having confused ___domain knowledge with program design knowledge.

The paper claims the following four major efforts that the authors of HtDP have made to address perceived issues with SICP:

#HtDP addresses explicitly, rather than implicitly, how programs should be constructed.

#To make programming easier, the book guides students through five different knowledge levels corresponding to data definition levels of complexity.

#The book's exercises focus on program design guidelines, rather than ___domain knowledge.

#The book assumes less ___domain knowledge than that of SICP.

The paper then distinguishes between structural [[recursion]], where the related data definition happens to be [[self-referential]], requiring usually a straightforward design process, and generative recursion, where new problem data is generated in the middle of the problem-solving process and the problem solving method is re-used, often requiring ''ad hoc'' mathematical insight, and stresses how this distinction makes their approach scalable to the [[Object-oriented programming|object-oriented]] (OO) world.

Finally, the paper concludes with a description of responses from various faculty and students after having used HtDP in the classroom.

== References ==

{{Reflist}}

== External links ==

* {{Official website|htdp.org}}, 2018 2nd edition, 2003 1st edition

{{Lisp programming language}}

[[Category:2001 non-fiction books]]

[[Category:Computer science books]]

[[Category:TextbooksMIT Press books]]

[[Category:Computer programming books]]

[[Category:Scheme (programming language)]]

[[Category:Creative Commons-licensed books]]