Allow customising goto label indentation

[Matthew Wilcox]

[I sent this to the Debian bug-tracking system a couple of months ago.
There's been no response to it, so I dug around a bit and found this
mailing list]

I like my source code to have a one space indent before the goto label,
like this:

int foo(void)
{
        bar();
 quux:
}

The current code hardcodes an indentation of two columns less than the
current indentation.  This patch allows you to configure a negative
displacement from the current indent level, or a positive absolute
displacement.  So I can now invoke indent as:

$ indent -kr -i8 -li1

and get the style I prefer.

Notice that -li0 will give you a label in the first column.  -li-2 will
give the current, and default behaviour.

Here's the patch to implement that.  I even added documentation!

diff -u indent-2.2.9/src/indent.h indent-2.2.9/src/indent.h
--- indent-2.2.9/src/indent.h
+++ indent-2.2.9/src/indent.h
@@ -80,6 +80,8 @@
 
 #define DEFAULT_RIGHT_COMMENT_MARGIN 78
 
+#define DEFAULT_LABEL_INDENT -2
+
 /* Name of input file.  */
 extern char *in_name;
 
@@ -201,6 +203,7 @@
     int leave_preproc_space; /* if true, leave the spaces between  '#' and 
preprocessor commands. */
     int force_preproc_width; /* if this is >0, this becomes the preproc 
indent-level */
     int lineup_to_parens;    /* if true, continued code within parens will be 
lined up to the open paren */
+    int label_indent;       /* if >0 an absolute indent, if <0 relative to 
curret indent level */
     int honour_newlines;     /* True when positions at which we read a newline 
in the input file, should get
                               * a high priority to break long lines at. */
     int format_comments; /* If any comments are to be reformatted */
--- indent-2.2.9.orig/doc/indent.texinfo
+++ indent-2.2.9/doc/indent.texinfo
@@ -1188,6 +1188,16 @@
 columns wide, but (as of version 1.2) may be changed by the @option{-ts}
 option.  Tabs are treated as the equivalent number of spaces.
 
address@hidden address@hidden
address@hidden address@hidden
+The indentation of goto labels is controlled by the @option{-li} parameter.  If
+it is set to zero or a positive number, this indicates how far from the left
+margin to indent a label.  If it is set to a negative number, this indicates
+how far back from the current indent level to place the label.  The default
+setting is -2 which matches the behaviour of earlier versions of indent.
+Note that this parameter does not affect the placing of case labels; see the
address@hidden parameter for that.
+
 @kindex address@hidden
 @kindex address@hidden
 @kindex -nip
@@ -1656,6 +1666,11 @@
 Set maximum line length for comment formatting to @address@hidden
 @xref{Comments}.
 
address@hidden address@hidden
address@hidden address@hidden
+Set indentation for labels to @address@hidden
address@hidden
+
 @item -lp
 @itemx --continue-at-parentheses
 Line up continued lines at address@hidden
--- indent-2.2.9.orig/src/io.c
+++ indent-2.2.9/src/io.c
@@ -54,9 +54,6 @@
 
 RCSTAG_CC ("$Id: io.c,v 1.50 2002/08/04 17:08:41 david Exp $");
 
-/* number of levels a label is placed to left of code */
-#define LABEL_OFFSET 2
-
 
/******************************************************************************/
 /* Stuff that needs to be shared with the rest of indent. Documented in
  * indent.h.
@@ -312,9 +309,14 @@
         /* FIXME: does this belong here at all? */
         return 1;
     }
+
+    if (settings.label_indent < 0)
+    {
+        return parser_state_tos->ind_level + settings.label_indent + 1;
+    }
     else
     {
-        return parser_state_tos->ind_level - LABEL_OFFSET + 1;
+        return settings.label_indent + 1;
     }
 }
 
--- indent-2.2.9.orig/src/args.c
+++ indent-2.2.9/src/args.c
@@ -125,6 +125,7 @@
 static int exp_kr   = 0;
 static int exp_l    = 0;
 static int exp_lc   = 0;
+static int exp_li   = 0;
 static int exp_lp   = 0;
 static int exp_lps  = 0;
 static int exp_nip  = 0; 
@@ -252,6 +253,7 @@
     {"nbacc",   PRO_BOOL,                           false,      OFF, 
&settings.blanklines_around_conditional_compilation, &exp_bacc},
     {"lps",     PRO_BOOL,                           false,       ON, 
&settings.leave_preproc_space,              &exp_lps},
     {"lp",      PRO_BOOL,                            true,       ON, 
&settings.lineup_to_parens,                 &exp_lp},
+    {"li",      PRO_INT,             DEFAULT_LABEL_INDENT, ONOFF_NA, 
&settings.label_indent,                     &exp_li},
     {"lc",      PRO_INT,     DEFAULT_RIGHT_COMMENT_MARGIN, ONOFF_NA, 
&settings.comment_max_col,                  &exp_lc},
     {"l",       PRO_INT,             DEFAULT_RIGHT_MARGIN, ONOFF_NA, 
&settings.max_col,                          &exp_l},
     {"kr",      PRO_SETTINGS,                           0, ONOFF_NA, 
KR_SETTINGS_STRING,                         &exp_kr},
@@ -365,6 +367,7 @@
     {"nbacc",   PRO_BOOL,                           false,      OFF, 
&settings.blanklines_around_conditional_compilation, &exp_bacc},
     {"lps",     PRO_BOOL,                           false,       ON, 
&settings.leave_preproc_space,              &exp_lps},
     {"lp",      PRO_BOOL,                            true,       ON, 
&settings.lineup_to_parens,                 &exp_lp},
+    {"li",      PRO_INT,             DEFAULT_LABEL_INDENT, ONOFF_NA, 
&settings.label_indent,                     &exp_li},
     {"lc",      PRO_INT,     DEFAULT_RIGHT_COMMENT_MARGIN, ONOFF_NA, 
&settings.comment_max_col,                  &exp_lc},
     {"l",       PRO_INT,             DEFAULT_RIGHT_MARGIN, ONOFF_NA, 
&settings.max_col,                          &exp_l},
     {"kr",      PRO_SETTINGS,                           0, ONOFF_NA, 
KR_SETTINGS_STRING,                         &exp_kr},
@@ -475,6 +478,7 @@
     {"left-justify-declarations",                   "dj"},
     {"leave-preprocessor-space",                    "lps"},
     {"leave-optional-blank-lines",                  "nsob"},
+    {"label-indentation",                           "li"},
     {"kernighan-and-ritchie-style",                 "kr"},
     {"kernighan-and-ritchie",                       "kr"},
     {"k-and-r-style",                               "kr"},

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."