まくまくPythonノート
Java や C/C++ のコード中のコメントを削除する
下記の filter_java_comment 関数は、受け取った Java や C/C++ のコードからコメントを削除して返します。
C 言語の /* ... */ というスタイルのコメントと、C++ 言語の // ... というスタイルのコメント両方を削除します。
from enum import Enum
class State(Enum):
CODE = 1
C_COMMENT = 2
CPP_COMMENT = 3
STRING_LITERAL = 4
def filter_java_comment(text):
""" Removes Java (C/C++) style comments from text. """
result = [] # filtered text (char array)
prev = '' # previous char
prevprev = '' # previous previous char
state = State.CODE
for ch in text:
# Skip to the end of C-style comment
if state == State.C_COMMENT:
if prevprev != '\\' and prev == '*' and ch == '/': # End comment
state = State.CODE
prevprev = prev = ''
elif ch == '\n':
result.append('\n')
prevprev = prev = ''
else:
prevprev, prev = prev, ch
continue
# Skip to the end of the line (C++ style comment)
if state == State.CPP_COMMENT:
if ch == '\n': # End comment
state = State.CODE
result.append('\n')
prevprev = prev = ''
continue
# Skip to the end of the string literal
if state == State.STRING_LITERAL:
if prev != '\\' and ch == '"': # End literal
state = State.CODE
result.append(prev)
prevprev, prev = prev, ch
continue
# Starts C-style comment?
if prevprev != '\\' and prev == '/' and ch == '*':
state = State.C_COMMENT
prevprev = prev = ''
continue
# Starts C++ style comment?
if prevprev != '\\' and prev == '/' and ch == '/':
state = State.CPP_COMMENT
prevprev = prev = ''
continue
# Comment has not started yet
if prev: result.append(prev)
# Starts string literal?
if ch == '"':
state = State.STRING_LITERAL
prevprev, prev = prev, ch
# Returns filtered text
if prev: result.append(prev)
return ''.join(result)
if __name__ == '__main__':
with open('Sample.java', encoding='utf-8') as f:
content = f.read() # テキストファイルを一括読み込み
print(filter_java_comment(content))
public class Sample {
/**
* Greets someone.
* @param name the name of who you want to greet
*/
public void greet(String name) {
// Dummy comment
System.out.println("Hello " + name);
/* Dummy *//* Dummy */
}
}
public class Sample {
public void greet(String name) {
System.out.println("Hello " + name);
}
}
改行はバッチリ残しているので、フィルタ後のコード行数は変化しません。
