用注释注释Python print()输出

Question

给定带有print()语句的Python脚本,我希望能够运行脚本并在显示每个语句输出的每个语句后插入注释.要演示,请将此脚本命名为example.py:

a, b = 1, 2

print('a + b:', a + b)

c, d = 3, 4

print('c + d:', c + d)

期望的输出是:

a, b = 1, 2

print('a + b:', a + b)
# a + b: 3

c, d = 3, 4

print('c + d:', c + d)
# c + d: 7

这是我的尝试,适用于上面的简单示例:

import sys
from io import StringIO

def intercept_stdout(func):
    "redirect stdout from a target function"
    def wrapper(*args, **kwargs):
        "wrapper function for intercepting stdout"
        # save original stdout
        original_stdout = sys.stdout

        # set up StringIO object to temporarily capture stdout
        capture_stdout = StringIO()
        sys.stdout = capture_stdout

        # execute wrapped function
        func(*args, **kwargs)

        # assign captured stdout to value
        func_output = capture_stdout.getvalue()

        # reset stdout
        sys.stdout = original_stdout

        # return captured value
        return func_output

    return wrapper


@intercept_stdout
def exec_target(name):
    "execute a target script"
    with open(name, 'r') as f:    
        exec(f.read())


def read_target(name):
    "read source code from a target script & return it as a list of lines"
    with open(name) as f:
        source = f.readlines()

    # to properly format last comment, ensure source ends in a newline
    if len(source[-1]) >= 1 and source[-1][-1] != '\n':
        source[-1] += '\n'

    return source


def annotate_source(target):
    "given a target script, return the source with comments under each print()"
    target_source = read_target(target)

    # find each line that starts with 'print(' & get indices in reverse order
    print_line_indices = [i for i, j in enumerate(target_source)
                              if len(j) > 6 and j[:6] == 'print(']
    print_line_indices.reverse()

    # execute the target script and get each line output in reverse order
    target_output = exec_target(target)
    printed_lines = target_output.split('\n')
    printed_lines.reverse()

    # iterate over the source and insert commented target output line-by-line
    annotated_source = []
    for i, line in enumerate(target_source):
        annotated_source.append(line)
        if print_line_indices and i == print_line_indices[-1]:
            annotated_source.append('# ' + printed_lines.pop() + '\n')
            print_line_indices.pop()

    # return new annotated source as a string
    return ''.join(annotated_source)


if __name__ == '__main__':
    target_script = 'example.py'
    with open('annotated_example.py', 'w') as f:
        f.write(annotate_source(target_script))

但是,对于print()语句跨越多行的脚本以及print()不在行开头的语句,它会失败.在最好的情况下,它甚至可以用于print()函数内的语句.请看以下示例:

print('''print to multiple lines, first line
second line
third line''')

print('print from partial line, first part') if True else 0

1 if False else print('print from partial line, second part')

print('print from compound statement, first part'); pass

pass; print('print from compound statement, second part')

def foo():
    print('bar')

foo()

理想情况下,输出看起来像这样:

print('''print to multiple lines, first line
second line
third line''')
# print to multiple lines, first line
# second line
# third line

print('print from partial line, first part') if True else 0
# print from partial line, first part

1 if False else print('print from partial line, second part')
# print from partial line, second part

print('print from compound statement, first part'); pass
# print from compound statement, first part

pass; print('print from compound statement, second part')
# print from compound statement, second part

def foo():
    print('bar')

foo()
# bar

但上面的脚本就像这样破坏它:

print('''print to multiple lines, first line
# print to multiple lines, first line
second line
third line''')

print('print from partial line, first part') if True else 0
# second line

1 if False else print('print from partial line, second part')

print('print from compound statement, first part'); pass
# third line

pass; print('print from compound statement, second part')

def foo():
    print('bar')

foo()

什么方法可以使这个过程更加健壮？

Answer 1

你考虑过使用这个inspect模块吗？如果您愿意说您总是希望最顶层呼叫旁边的注释,并且您正在注释的文件很简单,您可以获得合理的结果.以下是我的尝试,它会覆盖内置的print函数并查看堆栈跟踪以确定调用的位置:

import inspect
import sys
from io import StringIO

file_changes = {}

def anno_print(old_print, *args, **kwargs):
    (frame, filename, line_number,
     function_name, lines, index) = inspect.getouterframes(inspect.currentframe())[-2]
    if filename not in file_changes:
        file_changes[filename] = {}
    if line_number not in file_changes[filename]:
        file_changes[filename][line_number] = []
    orig_stdout = sys.stdout
    capture_stdout = StringIO()
    sys.stdout = capture_stdout
    old_print(*args, **kwargs)
    output = capture_stdout.getvalue()
    file_changes[filename][line_number].append(output)
    sys.stdout = orig_stdout
    return

def make_annotated_file(old_source, new_source):
    changes = file_changes[old_source]
    old_source_F = open(old_source)
    new_source_F = open(new_source, 'w')
    content = old_source_F.readlines()
    for i in range(len(content)):
        line_num = i + 1
        new_source_F.write(content[i])
        if content[i][-1] != '\n':
            new_source_F.write('\n')
        if line_num in changes:
            for output in changes[line_num]:
                output = output[:-1].replace('\n', '\n#') + '\n'
                new_source_F.write("#" + output)
    new_source_F.close()



if __name__=='__main__':
    target_source = "foo.py"
    old_print = __builtins__.print
    __builtins__.print = lambda *args, **kwargs: anno_print(old_print, *args, **kwargs)
    with open(target_source) as f:
        code = compile(f.read(), target_source, 'exec')
        exec(code)
    __builtins__.print = old_print
    make_annotated_file(target_source, "foo_annotated.py")

如果我在以下文件"foo.py"上运行它:

def foo():
    print("a")
    print("b")

def cool():
    foo()
    print("c")

def doesnt_print():
    a = 2 + 3

print(1+2)
foo()
doesnt_print()
cool()

输出是"foo_annotated.py":

def foo():
    print("a")
    print("b")

def cool():
    foo()
    print("c")

def doesnt_print():
    a = 2 + 3

print(1+2)
#3
foo()
#a
#b
doesnt_print()
cool()
#a
#b
#c