| 1 | # assert.pl |
| 2 | # tchrist@convex.com (Tom Christiansen) |
| 3 | # |
| 4 | # Usage: |
| 5 | # |
| 6 | # &assert('@x > @y'); |
| 7 | # &assert('$var > 10', $var, $othervar, @various_info); |
| 8 | # |
| 9 | # That is, if the first expression evals false, we blow up. The |
| 10 | # rest of the args, if any, are nice to know because they will |
| 11 | # be printed out by &panic, which is just the stack-backtrace |
| 12 | # routine shamelessly borrowed from the perl debugger. |
| 13 | |
| 14 | sub assert { |
| 15 | &panic("ASSERTION BOTCHED: $_[$[]",$@) unless eval $_[$[]; |
| 16 | } |
| 17 | |
| 18 | sub panic { |
| 19 | package DB; |
| 20 | |
| 21 | select(STDERR); |
| 22 | |
| 23 | print "\npanic: @_\n"; |
| 24 | |
| 25 | exit 1 if $] <= 4.003; # caller broken |
| 26 | |
| 27 | # stack traceback gratefully borrowed from perl debugger |
| 28 | |
| 29 | local $_; |
| 30 | my $i; |
| 31 | my ($p,$f,$l,$s,$h,$a,@a,@frames); |
| 32 | for ($i = 0; ($p,$f,$l,$s,$h,$w) = caller($i); $i++) { |
| 33 | @a = @args; |
| 34 | for (@a) { |
| 35 | if (/^StB\000/ && length($_) == length($_main{'_main'})) { |
| 36 | $_ = sprintf("%s",$_); |
| 37 | } |
| 38 | else { |
| 39 | s/'/\\'/g; |
| 40 | s/([^\0]*)/'$1'/ unless /^-?[\d.]+$/; |
| 41 | s/([\200-\377])/sprintf("M-%c",ord($1)&0177)/eg; |
| 42 | s/([\0-\37\177])/sprintf("^%c",ord($1)^64)/eg; |
| 43 | } |
| 44 | } |
| 45 | $w = $w ? '@ = ' : '$ = '; |
| 46 | $a = $h ? '(' . join(', ', @a) . ')' : ''; |
| 47 | push(@frames, "$w&$s$a from file $f line $l\n"); |
| 48 | } |
| 49 | for ($i=0; $i <= $#frames; $i++) { |
| 50 | print $frames[$i]; |
| 51 | } |
| 52 | exit 1; |
| 53 | } |
| 54 | |
| 55 | 1; |