ITEC 380 2008fall ibarland

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lect01b
Scheme intro

- go over course-info
- languages;
   examples: enscript -o foo.ps       (wimpout.ps)
   also, sh: Example: cd ~/Unix 
                      find . -name \*.ps -print
                      find . -name \*.ps -print | grep -i wimpout
- How to call a function:
   Java:  obj.meth(...)
          class.meth(...)
          meth(...)
          new ClassName(...)
          a + b
          !a
          arr[i]           Cf. List.get(i)
          arr[i] = ...     Cf. List.set(i,...)
- Left with the question: pros/cons of having 
  operators, as distinct from functions?
  - pro: more natural for human readers
  - con: a different syntax (harder for compiler-writer; learning?) 
  - con: requires(?) that those characters are reserved 
  - con: 37 operators with 14 levels of precedence:
         http://www.cs.wisc.edu/~willb/cs302/java-operator-precedence.pdf

2.0-1.1
25*(7/25)


- Scheme overview:
   - Values:  2, 3.8, #i3.8, "hello", 'orange, >insert-image;  true, false
       (symbols are like enumerated types)
 
(Got to here)
   - Placeholders
      (define a 4.2)
      (define z 2.7)
      (define ufo >insert-image)
   - expressions
      (/ (+ (- b) (sqrt (- (* b b) (* 4 a c)))) 
         (* 2 a))

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©2008, Ian Barland, Radford University Last modified 2008.Sep.06 (Sat)

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