anonymous procedures

anonymous numbers

• the expression (* (+ 2 3) 4)) contains the subexpression (+ 2 3)
• we could introduced a name for the subexpression’s value instead
  with (define i (+ 2 3)) and then written (* i 4)
  
• but it’s convenient to have anonymous values

anonymous procedures

• compare this to
  (define (square i) (* i i))
  
  (square 5)
• what if we want to make the squaring procedure anonymous?
• we can write an expression whose value is the squaring procedure like this:
  (lambda (i) (* i i))
  
• now for (square 5), we can write
  ((lambda (i) (* i i)) 5)
  

is this a big deal?

• we’ll see more compelling uses of lambda later
• lambda will allow us to construct a procedure on the fly

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