insert_insert.py

import copy

def convert_for_transform(op1, op2):
    new_op_1 = {}
    new_op_2 = {}
    for j in op1:
        for i in j:
            if i == "retain":
                op1_index = j[i]
                new_op_1['index'] = op1_index
            if i == "insert":
                op1_char = j[i]
                new_op_1['insert'] = op1_char
    for j in op2:
        for i in j:
            if i == "retain":
                op2_index = j[i]
                new_op_2['index'] = op2_index
            if i == "insert":
                op2_char = j[i]
                new_op_2['insert'] = op2_char
    return new_op_1, new_op_2

def transform(op1, op2):
    op1, op2 = convert_for_transform(op1, op2)
    transform_type = []
    if "insert" in op1:
        transform_type.append('Ins')
    if "insert" in op2:
        transform_type.append('Ins')
    
    sop1 = copy.deepcopy(op1)
    sop2 = copy.deepcopy(op2)
    
    if transform_type[0] == "Ins" and transform_type[1] == "Ins":
        transformed_ops = insert_insert(op1, op2), insert_insert(sop2, sop1)
    # Inserting characters at the same index.
    # The fix is to make both operations agree on 
    # which one to insert first (order matters)
    # so that they don't insert at different times.
    if transformed_ops[0]['index'] == transformed_ops[1]['index']:
        transformed_ops[0]['index'] = sop1['index']
    return transformed_ops[0], transformed_ops[1]

def insert_insert(op1, op2):
    if op1['index'] < op2['index']:
        op1_prime = op1
    else:
        op1['index'] = op1['index'] + (len(op2['insert']))
        op1_prime = op1
    return op1_prime

# Example usage:
op1 = [{"retain": 0}, {"insert": "a\n"}]
op2 = [{"retain": 0}, {"insert": "O"}]
new_ops = transform(op1, op2, verbose=True)

print("Original op1:", op1)
print("Original op2:", op2)
print("Transformed op:", new_ops)