On 9/22/2013 7:50 AM, Andrej Mitrovic wrote:
I run into these all the time, and I have to spend half a minute
scanning left and right trying to figure out where the damn missing
brace went. Marginal benefit my ass.
I programmed into my editor (MicroEmacs) the F3 command. F3, when sitting on one
of ()[]{}<> will find the matching character, even if nested. If it is not on
one of those characters, it finds the next occurrence of that character.
As a bonus, if it is on the # character at the beginning of the line, it will
find the matching #if, #ifdef, #elif, #else, or #endif :-)
I find it very, very handy.
It's based on an elithp macro written for Emacs back in the 1980's. If your
editor has any ability to have user-written extensions, this is a simple one,
and I highly recommend it. Here's the corresponding MicroEmacs implementation:
-----------------------------------------------------------------------
/*********************************
* Examine line at '.'.
* Returns:
* HASH_xxx
* 0 anything else
*/
#define HASH_IF 1
#define HASH_ELIF 2
#define HASH_ELSE 3
#define HASH_ENDIF 4
static int ifhash(clp)
LINE *clp;
{
register int len;
register int i,h;
static char *hash[] = {"if","elif","else","endif"};
len = llength(clp);
if (len < 3 || lgetc(clp,0) != '#')
goto ret0;
for (i = 1; ; i++)
{
if (i >= len)
goto ret0;
if (!isspace(lgetc(clp,i)))
break;
}
for (h = 0; h < arraysize(hash); h++)
if (len - i >= strlen(hash[h]) &&
memcmp(&clp->l_text[i],hash[h],strlen(hash[h])) == 0)
return h + 1;
ret0:
return 0;
}
/*********************************
* Search for the next occurence of the character at '.'.
* If character is a (){}[]<>, search for matching bracket.
* If '.' is on #if, #elif, or #else search for next #elif, #else or #endif.
* If '.' is on #endif, search backwards for corresponding #if.
*/
int search_paren(f, n)
{
register LINE *clp;
register int cbo;
register int len;
register int i;
char chinc,chdec,ch;
int count;
int forward;
int h;
static char bracket[][2] = {{'(',')'},{'<','>'},{'[',']'},{'{','}'}};
clp = curwp->w_dotp; /* get pointer to current line */
cbo = curwp->w_doto; /* and offset into that line */
count = 0;
len = llength(clp);
if (cbo >= len)
chinc = '\n';
else
chinc = lgetc(clp,cbo);
if (cbo == 0 && (h = ifhash(clp)) != 0)
{ forward = h != HASH_ENDIF;
}
else
{
if (inword())
{ // Search for word the cursor is currently on
int s;
do
s = backchar(FALSE, 1);
while (s && inword());
if (s && forwchar(FALSE, 1))
{
int start = curwp->w_doto;
if (word_forw(FALSE, 1))
{
cbo = curwp->w_doto;
int i;
for (i = 0; i < NPAT - 1 && start + i < cbo; i++)
{
pat[i] = lgetc(clp, start + i);
}
pat[i] = 0;
if (Dsearchagain(f, n))
return backchar(FALSE, 1);
}
}
mlwrite("Not found");
return FALSE;
}
forward = TRUE; /* forward */
h = 0;
chdec = chinc;
for (i = 0; i < 4; i++)
if (bracket[i][0] == chinc)
{ chdec = bracket[i][1];
break;
}
for (i = 0; i < 4; i++)
if (bracket[i][1] == chinc)
{ chdec = bracket[i][0];
forward = FALSE; /* search backwards */
break;
}
}
while (1) /* while not end of buffer */
{
if (forward)
{
if (h || cbo >= len)
{
clp = lforw(clp);
if (clp == curbp->b_linep) /* if end of buffer */
break;
len = llength(clp);
cbo = 0;
}
else
cbo++;
}
else /* backward */
{
if (h || cbo == 0)
{
clp = lback(clp);
if (clp == curbp->b_linep)
break;
len = llength(clp);
cbo = len;
}
else
--cbo;
}
if (h)
{ int h2;
cbo = 0;
h2 = ifhash(clp);
if (h2)
{ if (h == HASH_ENDIF)
{
if (h2 == HASH_ENDIF)
count++;
else if (h2 == HASH_IF)
{ if (count-- == 0)
goto found;
}
}
else
{ if (h2 == HASH_IF)
count++;
else
{ if (count == 0)
goto found;
if (h2 == HASH_ENDIF)
count--;
}
}
}
}
else
{
ch = (cbo < len) ? lgetc(clp,cbo) : '\n';
if (eq(ch,chdec))
{ if (count-- == 0)
{
/* We've found it */
found:
curwp->w_dotp = clp;
curwp->w_doto = cbo;
curwp->w_flag |= WFMOVE;
return (TRUE);
}
}
else if (eq(ch,chinc))
count++;
}
}
mlwrite("Not found");
return (FALSE);
}
