Module: RubyLLM::Toolbox::TextDiff

Defined in:
lib/ruby_llm/toolbox/text_diff.rb

Overview

Line-based diff via longest-common-subsequence. Produces a readable diff (‘-’/‘+’/‘ ’ prefixes) with long unchanged runs elided. Pure stdlib.

Class Method Summary collapse

Class Method Details

.diff_ops(a, b) ⇒ Object 



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# File 'lib/ruby_llm/toolbox/text_diff.rb', line 19

def diff_ops(a, b)
  n = a.size
  m = b.size
  lcs = Array.new(n + 1) { Array.new(m + 1, 0) }
  (n - 1).downto(0) do |i|
    (m - 1).downto(0) do |j|
      lcs[i][j] = a[i] == b[j] ? lcs[i + 1][j + 1] + 1 : [lcs[i + 1][j], lcs[i][j + 1]].max
    end
  end

  ops = []
  i = 0
  j = 0
  while i < n && j < m
    if a[i] == b[j]
      ops << [:eq, a[i]]
      i += 1
      j += 1
    elsif lcs[i + 1][j] >= lcs[i][j + 1]
      ops << [:del, a[i]]
      i += 1
    else
      ops << [:add, b[j]]
      j += 1
    end
  end
  ops.concat(a[i..].map { |line| [:del, line] }) if i < n
  ops.concat(b[j..].map { |line| [:add, line] }) if j < m
  ops
end

.emit_context(out, run, context) ⇒ Object 



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# File 'lib/ruby_llm/toolbox/text_diff.rb', line 70

def emit_context(out, run, context)
  if run.size > (context * 2) + 1
    run.first(context).each { |line| out << "  #{line.chomp}" }
    out << "  ⋮ (#{run.size - (context * 2)} unchanged lines)"
    run.last(context).each { |line| out << "  #{line.chomp}" }
  else
    run.each { |line| out << "  #{line.chomp}" }
  end
end

.render(ops, old_label, new_label, context) ⇒ Object 



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# File 'lib/ruby_llm/toolbox/text_diff.rb', line 50

def render(ops, old_label, new_label, context)
  out = ["--- #{old_label}", "+++ #{new_label}"]
  i = 0
  while i < ops.size
    type, line = ops[i]
    if type == :eq
      run = []
      while i < ops.size && ops[i][0] == :eq
        run << ops[i][1]
        i += 1
      end
      emit_context(out, run, context)
    else
      out << "#{type == :del ? '-' : '+'} #{line.chomp}"
      i += 1
    end
  end
  out.join("\n")
end

.unified(old_text, new_text, old_label: "old", new_label: "new", context: 3) ⇒ Object 



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# File 'lib/ruby_llm/toolbox/text_diff.rb', line 10

def unified(old_text, new_text, old_label: "old", new_label: "new", context: 3)
  a = old_text.to_s.lines
  b = new_text.to_s.lines
  ops = diff_ops(a, b)
  return "(no differences)" if ops.all? { |type, _| type == :eq }

  render(ops, old_label, new_label, context)
end