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Lecture 17

Lecture 17. Programming Languages (S&G, ch. 8). Read S&G ch. 9 (Compilers and Language Translation). The Phenomenology of Tools. Phenomenology. A philosophical method A phenomenon is some aspect of concrete human experience of the world

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Lecture 17

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  1. Lecture 17 Programming Languages (S&G, ch. 8) CS 100 - Lecture 17

  2. Read S&G ch. 9(Compilers and Language Translation) CS 100 - Lecture 17

  3. The Phenomenology of Tools CS 100 - Lecture 17

  4. Phenomenology • A philosophical method • A phenomenon is some aspect of concrete human experience of the world • Phenomenology investigates the invariant structure of some phenomenon by systematic variation of that experience • Has its own technical terminology CS 100 - Lecture 17

  5. Phenomenology of Tools • The phenomena of concern are tools in the broadest sense • Developed by Don Ihde • Here we are concerned with tools related to computers: • computers themselves • programming languages • word processors • email • etc. CS 100 - Lecture 17

  6. Tools are Ampliative& Reductive • Example: using stick to knock down fruit • Ampliative aspects • Greater power or performance • Extended experience • Reductive aspects • Experience is less immediate • Action is channeled by the tool CS 100 - Lecture 17

  7. Examples • Consider ampliative & reductive aspects of: • eye glasses • automobiles • telephones • email • recorded music • internet • word processor CS 100 - Lecture 17

  8. Utopians vs. Dystopians • Technological utopians: • focus on ampliative aspects • emphasize practical advantages • Technological dystopians: • focus on reductive aspects • discount practical advantages • Both attitudes are reduced focuses • Better: • acknowledge essential ambivalence of our experience of the tool • “all technology is non-neutral” — Ihde CS 100 - Lecture 17

  9. Phenomenologyof Programming Languages • Ampliative aspect: • automation of tedious, error-prone activities • error checking • Reductive aspect: • loss of direct control of machine resources • possible inefficiency CS 100 - Lecture 17

  10. “Fascination” & “Fear” • Typical responses to a new technology • Utopians are fascinated by ampliative aspects • embrace & promote the new technology • tend to over-apply the new technology • inclined to further amplification • Dystopians fear reductive aspects • may view ampliative aspects as dangerous • ambivalent feelings of power or helplessness • Greater familiarity  balanced understanding of benefits & limitations CS 100 - Lecture 17

  11. Mastery & Embodiment • Tool replaces immediate (direct) with mediated (indirect) experience • When tool is mastered, its mediation becomes transparent (not invisible) • Contrast: • bad tool or unskillful use  experienced as object,relate to it • good tool & mastery  partially embodied,relate through it • With mastery, objectification becomes embodiment CS 100 - Lecture 17

  12. Focus & Action • Example: three writing technologies • dip pen • electric typewriter • word processor • Tools influence focus: • makes some aspects of situation salient,hides others • Tools influence action: • makes some actions easy, others awkward • Tools subtly influence what we notice and do CS 100 - Lecture 17

  13. Cultural Embedding • All technologies are culturally embedded • Our reactions to them are influenced by: • personal backgrounds • collective background • Stylistic inclinations may vary from user to user CS 100 - Lecture 17

  14. Conclusions • The phenomenology of tools helps us to: • understand people’s experience to tools • move beyond our own limited perspectives • understand social consequences of tools • exercise informed choice about adopting new technologies • design better tools • understand tool’s effect on focus & action • “All technology in non-neutral” CS 100 - Lecture 17

  15. Functional Programming CS 100 - Lecture 17

  16. Definition In functional programming, all programs are mathematical functions: • The arguments of the function are the inputs to the program • The computed value of the function is the only output from the program • There are no side-effects • The assignment statement is not used! CS 100 - Lecture 17

  17. functional program: function arguments result procedural program: procedure inputs output X side-effects Side-effects are hidden interfaces to a program Functions vs. Procedures with Side-Effects CS 100 - Lecture 17

  18. like a verb like the objects of the verb Scheme & LISP Syntax ( <function> <argument 1> <argument 2> … ) CS 100 - Lecture 17

  19. Examples • (log 2) — compute the logarithm of 2 and return it • (* 2 x) — compute the product of 2 and x • (list 3 4 5) — make a list out of the numbers 3, 4, and 5 • (define (double x) (* 2 x)) — define a function with the header “(double x)” and the body “(* 2 x)” • (double 4) — apply the user-defined function double to 4 CS 100 - Lecture 17

  20. Conditional Functions (if <condition><value if true> <value if false> ) (cond ( <condition 1><value if cond 1 true> ) ( <condition 2><value if cond 2 true> ) … ( else <value if all conds false> ) ) CS 100 - Lecture 17

  21. Run DrScheme CS 100 - Lecture 17

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