▼Datalog for PLT Scheme
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format-datum
format-variable
format-constant
format-term
format-literal
format-literals
format-clause
format-assertion
format-retraction
format-query
format-statement
format-program
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6 Pretty-Printing

This library provides facilities for pretty-printing Datalog source. It can be required via:

 (require (planet jaymccarthy/datalog:1:3/pretty))

This library depends on the pprint PLaneT package, which can be required via:

  (require (planet dherman/pprint:4))

See the documentation for pprint for information on how to use it.

(format-datum d) → doc?
  d : datum/c
Formats a datum.

Examples:

  > (pretty-print (format-datum 'sym))

  sym

  > (pretty-print (format-datum "str"))

  "str"

(format-variable v) → doc?
  v : variable?
Formats a variable.

Example:

  > (pretty-print (format-variable (make-variable #f 'Ancestor)))

  Ancestor

(format-constant c) → doc?
  c : constant?
Formats a constant.

Examples:

  > (pretty-print (format-constant (make-constant #f 'joseph)))

  joseph

  > (pretty-print (format-constant (make-constant #f "whom")))

  "whom"

(format-term t) → doc?
  t : term/c
Formats a term.

Examples:

  > (pretty-print (format-term (make-variable #f 'Ancestor)))

  Ancestor

  > (pretty-print (format-term (make-constant #f 'joseph)))

  joseph

  > (pretty-print (format-term (make-constant #f "whom")))

  "whom"

(format-literal l) → doc?
  l : literal?
Formats a literal.

Examples:

  > (pretty-print (format-literal (make-literal #f 'true (list))))

  true

  > (pretty-print
     (format-literal
      (make-literal #f 'ancestor
       (list (make-variable #f 'A) (make-constant #f 'jay)))))

  ancestor(A, jay)

  > (pretty-print
     (format-literal
      (make-literal #f '=
       (list (make-constant #f 'joseph) (make-constant #f 'jay)))))

  joseph = jay

(format-literals ls) → doc?
  ls : (listof literal?)
Formats a list of literals as assertions for formatting prove results.

Example:

  > (pretty-print
     (format-literals
      (list
       (make-literal #f 'true (list))
       (make-literal #f 'ancestor
        (list (make-constant #f 'joseph) (make-constant #f 'jay)))
       (make-literal #f '=
        (list (make-constant #f 'joseph) (make-constant #f 'jay))))))

  true.

  ancestor(joseph, jay).

  joseph = jay.

  

(format-clause c) → doc?
  c : clause?
Formats a clause.

Examples:

  > (pretty-print
     (format-clause
      (make-clause
       #f (make-literal #f 'ancestor
           (list (make-constant #f 'joseph)
                 (make-constant #f 'jay)))
       (list))))

  ancestor(joseph, jay)

  > (pretty-print
     (format-clause
      (make-clause
       #f (make-literal
           #f 'ancestor
           (list (make-constant #f 'A) (make-constant #f 'B)))
       (list (make-literal
              #f 'parent
              (list (make-constant #f 'A) (make-constant #f 'B)))))))

  ancestor(A, B) :- parent(A, B)

  > (pretty-print
     (format-clause
      (make-clause
       #f (make-literal
           #f 'ancestor
           (list (make-constant #f 'A) (make-constant #f 'B)))
       (list (make-literal
              #f 'parent
              (list (make-constant #f 'A) (make-constant #f 'C)))
             (make-literal
              #f 'ancestor
              (list (make-constant #f 'C) (make-constant #f 'B)))))))

  ancestor(A, B) :- parent(A, C), ancestor(C, B)

(format-assertion a) → doc?
  a : assertion?
Formats a assertion.

Example:

  > (pretty-print
     (format-assertion
      (make-assertion
       #f (make-clause
        #f (make-literal #f 'ancestor
            (list (make-constant #f 'joseph)
                  (make-constant #f 'jay)))
        (list)))))

  ancestor(joseph, jay).

(format-retraction r) → doc?
  r : retraction?
Formats a retraction.

Example:

  > (pretty-print
     (format-retraction
      (make-retraction
       #f (make-clause
        #f (make-literal #f 'ancestor
            (list (make-constant #f 'joseph)
                  (make-constant #f 'jay)))
        (list)))))

  ancestor(joseph, jay)~

(format-query q) → doc?
  q : query?
Formats a query.

Example:

  > (pretty-print
     (format-query
      (make-query
       #f (make-literal #f 'ancestor
           (list (make-constant #f 'joseph)
                 (make-constant #f 'jay))))))

  ancestor(joseph, jay)?

(format-statement s) → doc?
  s : statement/c
Formats a statement.

Example:

  > (pretty-print
     (format-statement
      (make-query
       #f (make-literal #f 'ancestor
           (list (make-constant #f 'joseph)
                 (make-constant #f 'jay))))))

  ancestor(joseph, jay)?

(format-program p) → doc?
  p : program/c
Formats a program.

Example:

  > (pretty-print
     (format-program
      (list
       (make-assertion
        #f (make-clause
         #f (make-literal #f 'ancestor
             (list (make-constant #f 'joseph)
                   (make-constant #f 'jay)))
         (list)))
       (make-query
        #f (make-literal #f 'ancestor
            (list (make-constant #f 'joseph)
                  (make-constant #f 'jay)))))))

  ancestor(joseph, jay).

  ancestor(joseph, jay)?

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