sexp-diff

Diffs s-expressions based on Levenshtein-like edit distance.

Documentation

DIFF-SEXP computes a diff between two s-expressions which minimizes the number of atoms in the result tree, also counting edit conditionals #:new, #:old. The OLD & NEW markers are parameterized.

[procedure] (sexp-diff OLD NEW) -> list

OLD: any ; original s-expression
NEW: any ; replacement s-expression

sexp-diff-markers

[parameter] (sexp-diff-markers [MARKERS]) -> (list keyword keyword)

MARKERS: (list keyword keyword) ; keywords for OLD & NEW.

Examples

 (sexp-diff
  '(DEFUN F (X) (+ (* X 2) 1))
  '(DEFUN F (X) (- (* X 2) 3 1)))

 ==>

 ((DEFUN F (X) (#:new - #:old + (* X 2) #:new 3 1)))

 (sexp-diff
  '(DEFUN F (X) (+ (* X 2) 4 1))
  '(DEFUN F (X) (- (* X 2) 5 3 1)))

 ==>

 ((DEFUN F (X) (#:new - #:old + (* X 2) #:new 5 #:new 3 #:old 4 1)))

 (parameterize ((sexp-diff-markers (list #:❌ #:✅)))
   (sexp-diff
    '(DEFUN F (X) (+ (* X 2) 4 4 1))
    '(DEFUN F (X) (- (* X 2) 5 5 3 1))) )

 ==>

 ((DEFUN F (X) (#:✅ - #:❌ + (* X 2) #:✅ 5 #:✅ 5 #:✅ 3 #:❌ 4 #:❌ 4 1)))