Tables with higher-order functions

Lecture overview -- Keyboard shortcut: 'u'

Previous page: Making tables with the real mirror -- Keyboard shortcut: 'p'

Next page: HTML element modifications -- Keyboard shortcut: 'n'

Lecture notes - all slides and notes together

Lecture 4 - Page 30 : 34

Functional Programming in Scheme
Higher-order Functions

Tables with higher-order functions

Instead of explicit composition of td and tr elements we can use a mapping to apply tr to rows and td to elements

Expression

Value

(define rows 
  '(("This" "is" "first" "row")
   ("This" "is" "second" "row")
   ("This" "is" "third" "row")
   ("This" "is" "fourth" "row"))
)

(table 'border 5
 (gmap
   (compose tr (gmap td)) rows))

This	is	first	row
This	is	second	row
This	is	third	row
This	is	fourth	row

In the table expression we map - at the outer level - a composition of tr and a td-mapper. The td-mapper is made by (gmap td).

The last example illustrates that (gmap td) is a useful building block, which can be composed with other functions.

The last example depends on the fact that the HTML mirror functions accept lists of elements and attributes.