如何将emacs C ++模式中的代码与“;”或“，”对齐？

Question

As a test engineer, I often have some spaghetti code like below:

  int *const cpe = &n; assert(42 == *cpe);
  int *const cpf = &cn; assert(42 == *cpf);
  int *const cpg = pcn; assert(42 == *cpg);
  int *const cph = cpcn; assert(42 == *cph);

For aesthetics, I would like to align them in columns defined by " ; ", like below:

  int *const cpe = &n;   assert(42 == *cpe);
  int *const cpf = &cn;  assert(42 == *cpf);
  int *const cpg = pcn;  assert(42 == *cpg);
  int *const cph = cpcn; assert(42 == *cph);

Is there a way in emacs to do this? (I know Mx align but it is not doing a neat job like desired.) Hopefully the method should also work with "," too.

Answer 1

(add-to-list 'align-rules-list
             '(c-assignment1
               (regexp . "[=;]\\(\\s-*\\)")
               (mode   . '(c-mode))
               (repeat . t)))

Simply Mx align works too, if you write this code.

Answer 2

In this particular case, you can just align on assert while the region is active:

M-x align-regexp assert RET

In general, the answer here is similar to the first part of my answer to your other question :

C-u M-x align-regexp RET ;\(\s-*\) RET RET RET n

will turn

  int *const cpe = &n; assert(42 == *cpe);
  int *const cpf = &cn; assert(42 == *cpf);
  int *const cpg = pcn; assert(42 == *cpg);
  int *const cph = cpcn; assert(42 == *cph);

into

  int *const cpe = &n;   assert(42 == *cpe);
  int *const cpf = &cn;  assert(42 == *cpf);
  int *const cpg = pcn;  assert(42 == *cpg);
  int *const cph = cpcn; assert(42 == *cph);

The same technique can be used to align on commas. Just replace the ; in the regular expression with , .