2 files changed, 47 insertions(+), 0 deletions(-)

M README.md
M src/simplediff.nim

@@ 31,6 31,8 @@ for diff in stringDiff("the word is blue", "the word is red", seps={' '}):
 
 Other convenience wrappers may be added in the future! Feel free to request one or submit a patch.
 
+See the `when isMainModule` block within `simplediff.nim` for an example of using these functions to build a simple diff application.
+
 ## Contributing
 
 Contributions are welcome! Please send patches, questions, requests, etc. to my [public inbox](mailto:~reesmichael1/public-inbox@lists.sr.ht).

@@ 71,3 71,48 @@ proc stringDiff*(s1, s2: string, seps: set[char] = Newlines): seq[Diff[string]] 
   ## Each entry of the returned seq is an instruction describing the
   ## shortest method of changing s1 into s2.
   return diff(split(s1, seps = seps), split(s2, seps = seps))
+
+
+when isMainModule:
+  import parseopt
+  import terminal
+
+  var p = initOptParser()
+  var oldFile, newFile: string
+  var argsSeen = 0
+  while true:
+    p.next()
+    case p.kind
+    of cmdEnd: break
+    of cmdShortOption, cmdLongOption:
+      stdout.write "unrecognized option: " & p.key & "\n"
+      quit(1)
+    of cmdArgument:
+      if argsSeen == 0:
+        oldFile = p.key
+        argsSeen += 1
+      elif argsSeen == 1:
+        newFile = p.key
+        argsSeen += 1
+      else:
+        argsSeen += 1
+
+  if argsSeen != 2:
+    stdout.write "usage: simplediff [old] [new]\n"
+    quit(1)
+
+  let diffed = stringDiff(readFile(oldFile), readFile(newFile))
+
+  for entry in diffed:
+    case entry.kind
+    of NoChange: discard
+    of Insertion:
+      for line in entry.tokens:
+        setForegroundColor(fgGreen)
+        writeStyled("++++ " & line & "\n", {styleBright})
+        setForegroundColor(fgDefault)
+    of Deletion:
+      for line in entry.tokens:
+        setForegroundColor(fgRed)
+        writeStyled("---- " & line & "\n", {styleBright})
+        setForegroundColor(fgDefault)