Module: AsciiChem::RingBonds

Defined in:
lib/asciichem/ring_bonds.rb

Overview

Derives ring bonds from atoms with matching ring_closures digits. Single source of truth for the "find ring bond pairs" algorithm — used by the Layout walker (to emit additional edges), the ModelAdapter walker (to emit additional canonical bonds), and the UnclosedRingCheck linter (to flag unmatched digits).

Algorithm: walk atoms in source order. For each digit on each atom, if we've seen it before (open ring), the current atom closes the ring — yield a RingBond pairing them, and clear the open record. Otherwise, record the current atom as the ring's opener.

Multiple digits on one atom (C12) open/close multiple rings in parallel. Digit "0" through "9" are supported in any order.

Defined Under Namespace

Classes: RingBond

Class Method Summary collapse

Class Method Details

.each_in(molecule) ⇒ Object

Yields each RingBond to the block. Walks the molecule in source order so from_atom always precedes to_atom.



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# File 'lib/asciichem/ring_bonds.rb', line 22

def self.each_in(molecule)
  open_rings = {}
  walk_atoms(molecule) do |atom|
    next unless atom.ring_closures

    atom.ring_closures.to_s.each_char do |digit|
      if open_rings.key?(digit)
        yield RingBond.new(digit: digit, from_atom: open_rings[digit], to_atom: atom)
        open_rings.delete(digit)
      else
        open_rings[digit] = atom
      end
    end
  end
end

.unclosed_atoms(molecule) ⇒ Object

Returns atoms whose ring_closures digits have no matching partner. Used by the UnclosedRingCheck linter.



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# File 'lib/asciichem/ring_bonds.rb', line 40

def self.unclosed_atoms(molecule)
  open_rings = {}
  unclosed = []
  walk_atoms(molecule) do |atom|
    next unless atom.ring_closures

    atom.ring_closures.to_s.each_char do |digit|
      if open_rings.key?(digit)
        open_rings.delete(digit)
      else
        open_rings[digit] = atom
      end
    end
  end
  open_rings.each_value { |atom| unclosed << atom }
  unclosed
end