Hi all,
I had a go at attempting to implement if-elsif-else-endif syntax for
FVWM so I can do things like this in my .fvwm2rc file:
(Much more intuitive/maintainable than using PipeRead.)
if xdpyinfo | /bin/grep -q XINERAMA
Echo "dual head system!"
Xinerama on
XineramaPrimaryScreen 0
DeskTopSize 4x1
else
Echo "NOT a dual head system."
DeskTopSize 6x1
endif
if [[ $(hostname) = "hamlet.denmark.org" ]]
Echo "This is SCoTT's home system"
elsif hostname | grep -q aao
Echo "This is SCoTT's work system"
endif
if [ -f someSlackwareFile ]
Echo "This is a Slackware system."
elsif [ -f /etc/someDebianFile ]
Echo "This is a Debian system."
elsif [ -f /etc/redhat-release ]
Echo "This is a RedHat system."
else
Echo "No idea what system this is."
endif
if [ $(cat /proc/meminfo | grep ^MemTotal | tr -s ' ' | cut -f2 -d' ') -gt
500000 ]
Echo "You have more than 0.5GB of RAM"
else
Echo "You need to upgrade."
endif
Unfortunately I don't know of a way to make this work with FvwmConsole.
Does anyone have any comments, suggestions, criticism, encouragement?
SCoTT. :)
Index: fvwm/read.c
===================================================================
RCS file: /home/cvs/fvwm/fvwm/fvwm/read.c,v
retrieving revision 1.60
diff -u -r1.60 read.c
--- fvwm/read.c 29 Jun 2003 19:53:23 -0000 1.60
+++ fvwm/read.c 29 Apr 2004 10:44:04 -0000
@@ -114,25 +114,16 @@
return curr_read_dir;
}
-
-/*
- * Read and execute each line from stream.
- */
-void run_command_stream(
- cond_rc_t *cond_rc, FILE *f, const exec_context_t *exc)
+/* __run_command_stream() - utility function for run_command_stream(). */
+void __run_command_stream(
+ cond_rc_t *cond_rc, FILE *f, const exec_context_t *exc,
+ Bool bInIf, Bool bIfTrue)
{
- char *tline;
+ char *tline, *tmp, *func = "__run_command_stream", *cond;
char line[1024];
+ Bool bIgnoreSection = !bIfTrue;
- /* Set close-on-exec flag */
- fcntl(fileno(f), F_SETFD, 1);
-
- /* Update window decorations in case we were called from a menu that
- * has now popped down. */
- handle_all_expose();
-
- tline = fgets(line, (sizeof line) - 1, f);
- while (tline)
+ while (NULL != (tline = fgets(line, (sizeof line) - 1, f)))
{
int l;
while (tline && (l = strlen(line)) < sizeof(line) && l >= 2 &&
@@ -150,6 +141,63 @@
{
tline[l - 1] = '\0';
}
+ /* remove leading whitespace */
+ tline = SkipSpaces(tline, NULL, 0);
+ /* ignore blank lines & comments. */
+ if (tline == NULL || tline[0] == '\0' || tline[0] == '#')
+ continue;
+
+ tmp = tline;
+ tmp = PeekToken(tmp, &cond);
+ if (strcasecmp(tmp, "if") == 0)
+ {
+ // fvwm_msg(DBG, func, "if-cmd=<%s>", cond);
+ bIfTrue = !system(cond);
+ // use recursion to allow nested if-statements.
+ __run_command_stream(cond_rc, f, exc, True, bIfTrue);
+ // at this point the complete if-statement has been
handled.
+ // ie. we've parsed the file all the way through to the
+ // matching "endif".
+ continue;
+ }
+ else if (strcasecmp(tmp, "elsif") == 0)
+ {
+ if (!bInIf)
+ fvwm_msg(ERR, func, "\"elsif\" not within
if-statement");
+ if (bIfTrue)
+ bIgnoreSection = True;
+ else
+ {
+ // fvwm_msg(DBG, func, "elsif-cmd=<%s>", cond);
+ bIfTrue = !system(cond);
+ bIgnoreSection = !bIfTrue;
+ }
+ continue;
+ }
+ else if (strcasecmp(tmp, "else") == 0)
+ {
+ if (!bInIf)
+ fvwm_msg(ERR, func, "\"else\" not within
if-statement");
+ if (bIfTrue)
+ bIgnoreSection = True;
+ else
+ {
+ bIfTrue = True;
+ bIgnoreSection = False;
+ }
+ continue;
+ }
+ else if (strcasecmp(tmp, "endif") == 0)
+ {
+ if (!bInIf)
+ fvwm_msg(ERR, func, "\"endif\" not within
if-statement");
+ else
+ return;
+ }
+
+ if (bInIf && bIgnoreSection)
+ continue;
+
if (debugging)
{
fvwm_msg(
@@ -158,12 +206,26 @@
exc->m.modnum, tline);
}
execute_function(cond_rc, exc, tline, 0);
- tline = fgets(line, (sizeof line) - 1, f);
}
return;
}
+/*
+ * Read and execute each line from stream.
+ */
+void run_command_stream(
+ cond_rc_t *cond_rc, FILE *f, const exec_context_t *exc)
+{
+ /* Set close-on-exec flag */
+ fcntl(fileno(f), F_SETFD, 1);
+
+ /* Update window decorations in case we were called from a menu that
+ * has now popped down. */
+ handle_all_expose();
+
+ __run_command_stream(cond_rc, f, exc, False, False);
+}
/**
* Parse the action string. We expect a filename, and optionally,
