This module implements an algorithm to compute the diff between two sequences of lines.

A basic example of diffInt on 2 arrays of integers:

import experimental/diff
echo diffInt([0, 1, 2, 3, 4, 5, 6, 7, 8], [-1, 1, 2, 3, 4, 5, 666, 7, 42])

Another short example of diffText to diff strings:

import experimental/diff
# 2 samples of text for testing (from "The Call of Cthulhu" by Lovecraft)
let txt0 = """I have looked upon all the universe has to hold of horror,
even skies of spring and flowers of summer must ever be poison to me."""
let txt1 = """I have looked upon all your code has to hold of bugs,
even skies of spring and flowers of summer must ever be poison to me."""

echo diffText(txt0, txt1)

To learn more see Diff on Wikipedia.

Imports

tables, strutils

Types

Item = object startA*: int ## Start Line number in Data A. startB*: int ## Start Line number in Data B. deletedA*: int ## Number of changes in Data A. insertedB*: int ## Number of changes in Data B.: An Item in the list of differences. Source Edit

Procs

proc diffInt(arrayA, arrayB: openArray[int]): seq[Item] {...}{.raises: [], tags: [].}

Find the difference in 2 arrays of integers.

arrayA A-version of the numbers (usually the old one)

arrayB B-version of the numbers (usually the new one)

Returns a sequence of Items that describe the differences.

Source Edit

proc diffText(textA, textB: string): seq[Item] {...}{.raises: [KeyError], tags: [].}

Find the difference in 2 text documents, comparing by textlines.

The algorithm itself is comparing 2 arrays of numbers so when comparing 2 text documents each line is converted into a (hash) number. This hash-value is computed by storing all textlines into a common hashtable so i can find duplicates in there, and generating a new number each time a new textline is inserted.

textA A-version of the text (usually the old one)

textB B-version of the text (usually the new one)

Returns a seq of Items that describe the differences.

Source Edit