Convert from underscores to camel case, if you randomly change conventions

lowerCamelCase.py

# converts the input string with underscores from eg lower_camel_case to lowerCamelCase (do you like what I did with the name there?)
# should work reasonably on anything with vaguely C-like syntax (not LISP probably, but who really cares?)

from contextlib import nested

def camelCaseWord(underscored):
    output_vals = []
    prev_idx = 0
    und_idx = underscored.find('_')
    while und_idx != -1:
        output_vals.append(underscored[prev_idx:und_idx])
        output_vals.append(underscored[und_idx+1:und_idx+2].upper())
        prev_idx = und_idx + 2
        und_idx = underscored.find('_', prev_idx)
    output_vals.append(underscored[prev_idx:])
    return ''.join(output_vals)

def camelCaseNonCaps(underscored):
    if any(c.islower() for c in underscored):
        return camelCaseWord(underscored)
    else:
        return underscored

def camelCaseLine(line):
    return re.sub(r"(\w+)", lambda m: camelCaseNonCaps(m.group()), line)
    
def camelCaseFile(input, output):
    with nested(open(input) as inf, open(output, 'w') as outf):
        for line in inf:
            outf.write(camelCaseLine(line))