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author | Fred Drake <fdrake@acm.org> | 1999-01-08 15:25:29 (GMT) |
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committer | Fred Drake <fdrake@acm.org> | 1999-01-08 15:25:29 (GMT) |
commit | 3fe1d326932432b1c27b75e9d3ce79f91dcfe1f8 (patch) | |
tree | 0074eae07130a12e34af18ec6c354367f653c19e /Doc/tools/checkargs.pm | |
parent | 41498435ba1f2901e2e3498d7f7f5c773a602568 (diff) | |
download | cpython-3fe1d326932432b1c27b75e9d3ce79f91dcfe1f8.zip cpython-3fe1d326932432b1c27b75e9d3ce79f91dcfe1f8.tar.gz cpython-3fe1d326932432b1c27b75e9d3ce79f91dcfe1f8.tar.bz2 |
New conversion tools for HTML->info from Michael Ernst
<mernst@cs.washington.edu>.
Thanks!
Diffstat (limited to 'Doc/tools/checkargs.pm')
-rw-r--r-- | Doc/tools/checkargs.pm | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/Doc/tools/checkargs.pm b/Doc/tools/checkargs.pm new file mode 100644 index 0000000..de52f69 --- /dev/null +++ b/Doc/tools/checkargs.pm @@ -0,0 +1,112 @@ +#!/uns/bin/perl + +package checkargs; +require 5.004; # uses "for my $var" +require Exporter; +@ISA = qw(Exporter); +@EXPORT = qw(check_args check_args_range check_args_at_least); +use strict; +use Carp; + +=head1 NAME + +checkargs -- Provide rudimentary argument checking for perl5 functions + +=head1 SYNOPSIS + + check_args(cArgsExpected, @_) + check_args_range(cArgsMin, cArgsMax, @_) + check_args_at_least(cArgsMin, @_) +where "@_" should be supplied literally. + +=head1 DESCRIPTION + +As the first line of user-written subroutine foo, do one of the following: + + my ($arg1, $arg2) = check_args(2, @_); + my ($arg1, @rest) = check_args_range(1, 4, @_); + my ($arg1, @rest) = check_args_at_least(1, @_); + my @args = check_args_at_least(0, @_); + +These functions may also be called for side effect (put a call to one +of the functions near the beginning of the subroutine), but using the +argument checkers to set the argument list is the recommended usage. + +The number of arguments and their definedness are checked; if the wrong +number are received, the program exits with an error message. + +=head1 AUTHOR + +Michael D. Ernst <F<mernst@cs.washington.edu>> + +=cut + +## Need to check that use of caller(1) really gives desired results. +## Need to give input chunk information. +## Is this obviated by Perl 5.003's declarations? Not entirely, I think. + +sub check_args ( $@ ) +{ + my ($num_formals, @args) = @_; + my ($pack, $file_arg, $line_arg, $subname, $hasargs, $wantarr) = caller(1); + if (@_ < 1) { croak "check_args needs at least 7 args, got ", scalar(@_), ": @_\n "; } + if ((!wantarray) && ($num_formals != 0)) + { croak "check_args called in scalar context"; } + # Can't use croak below here: it would only go out to caller, not its caller + my $num_actuals = @args; + if ($num_actuals != $num_formals) + { die "$file_arg:$line_arg: function $subname expected $num_formals argument", + (($num_formals == 1) ? "" : "s"), + ", got $num_actuals", + (($num_actuals == 0) ? "" : ": @args"), + "\n"; } + for my $index (0..$#args) + { if (!defined($args[$index])) + { die "$file_arg:$line_arg: function $subname undefined argument ", $index+1, ": @args[0..$index-1]\n"; } } + return @args; +} + +sub check_args_range ( $$@ ) +{ + my ($min_formals, $max_formals, @args) = @_; + my ($pack, $file_arg, $line_arg, $subname, $hasargs, $wantarr) = caller(1); + if (@_ < 2) { croak "check_args_range needs at least 8 args, got ", scalar(@_), ": @_"; } + if ((!wantarray) && ($max_formals != 0) && ($min_formals !=0) ) + { croak "check_args_range called in scalar context"; } + # Can't use croak below here: it would only go out to caller, not its caller + my $num_actuals = @args; + if (($num_actuals < $min_formals) || ($num_actuals > $max_formals)) + { die "$file_arg:$line_arg: function $subname expected $min_formals-$max_formals arguments, got $num_actuals", + ($num_actuals == 0) ? "" : ": @args", "\n"; } + for my $index (0..$#args) + { if (!defined($args[$index])) + { die "$file_arg:$line_arg: function $subname undefined argument ", $index+1, ": @args[0..$index-1]\n"; } } + return @args; +} + +sub check_args_at_least ( $@ ) +{ + my ($min_formals, @args) = @_; + my ($pack, $file_arg, $line_arg, $subname, $hasargs, $wantarr) = caller(1); + # Don't do this, because we want every sub to start with a call to check_args* + # if ($min_formals == 0) + # { die "Isn't it pointless to check for at least zero args to $subname?\n"; } + if (scalar(@_) < 1) + { croak "check_args_at_least needs at least 1 arg, got ", scalar(@_), ": @_"; } + if ((!wantarray) && ($min_formals != 0)) + { croak "check_args_at_least called in scalar context"; } + # Can't use croak below here: it would only go out to caller, not its caller + my $num_actuals = @args; + if ($num_actuals < $min_formals) + { die "$file_arg:$line_arg: function $subname expected at least $min_formals argument", + ($min_formals == 1) ? "" : "s", + ", got $num_actuals", + ($num_actuals == 0) ? "" : ": @args", "\n"; } + for my $index (0..$#args) + { if (!defined($args[$index])) + { warn "$file_arg:$line_arg: function $subname undefined argument ", $index+1, ": @args[0..$index-1]\n"; last; } } + return @args; +} + +1; # successful import +__END__ |