NAME
Scalar::Validation
Makes validation of scalar values or function (sub) parameters easy, is fast and uses pure Perl.
VERSION
This documentation refers to version 0.612 of Scalar::Validation
SYNOPSIS
use Scalar::Validation qw(:all);
my $int_1 = validate int_1 => Int => 123;
my $float_1 = validate float_1 => Float => 3.1415927;
my $para_1 = par parameter_1 => -Range => [1,5] => Int => shift;
my $exponent = npar -exponent => -Range => [1,5] => Int => \%options;
my $para_2 = parameter parameter_1 => -Range => [1,5] => Int => shift;
my $exponent_2 = named_parameter -exponent => -Range => [1,5] => Int => \%options;
my $int_2 = validate (int_2 => -And => [Scalar => 'Int'], 123);
my $int_3 = validate (int_3 => -Or => [Int => 'CodeRef'], 123);
my $code_ref = validate (code_ref => -Or => [Int => 'CodeRef'], sub { 123; });
my $enum_abc = validate (parameter => -Enum => {a => 1, b => 1, c => 1}, 'c');
my $enum_abc = validate (parameter => -Enum => [ qw (a b c) ], 'c');
my $int_4 = validate (int_4 => -Optional => Int => undef);
my $int_5 = validate (int_5 => -Optional => -And => [Scalar => Int => 0] => undef);
my $int_6 = validate (int_6 => -Optional => -Or => [Int => CodeRef => 0] => undef);
my $enum_2 = validate (enum_2 => -Optional => -Enum => {a => 1, b => 1, c => 1} => undef);
my $range_1 = validate (range_1 => -Optional => -Range => [1,5] => Int => undef);Just checks, never dies:
is_valid (valid_1 => Int => 123); # is valid, returns 1;
is_valid (valid_2 => Int => 1.23); # is not valid, returns 0;
is_valid (valid_3 => Int => 'a'); # is not valid, returns 0;
is_valid (valid_4 => Int => undef); # is not valid, returns 0;Free defined rules or wheres only (also for validate(...))
my $value = 2;
# be careful, doesn't check that $_ is an integer!
is_valid (free_where_greater_zero => sub { $_ && $_ > 0} => $value); # is valid, returns 1
is_valid (free_rule_greater_zero => { -as => Int =>
-where => sub { $_ > 0},
-message => sub { "$_ is not > 0" },
}
=> $value); # is valid, returns 1
my $my_rule = { -as => Int => -where => sub { $_ && $_ > 0} => -message => sub { "$_ is not > 0" }};
is_valid (free_rule_greater_zero => $my_rule => $value); # is valid, returns 1Managing Rules
declare_rule (
NegativeInt => -as => Int => # Parent rule is optional
-where => sub { $_ < 0 },
-message => sub { "value $_ is not a negative integer" },
);
replace_rule (
NegativeInt => -as => Int => # Parent rule is optional
-where => sub { $_ =< 0 },
-message => sub { "value $_ is not a negative integer" },
);
delete_rule ('NegativeInt');
rule_known(Unknown => 1); # returns 0 (false)
rule_known(Negative => 1); # returns 1 (true)Dynamic Rules For Comparison
par parameter => greater_than 4 => Int => shift; # = 5
validate parameter => g_t 4 => Int => $value; # = 6
is_valid (parameter => greater_equal 4 => Float => $value); # = 4.1
is_valid (parameter => g_e 4 => Int => $value); # = 4
npar -parameter => less_than 4 => Int => \%options;
is_valid (parameter => l_t (4 => 'Float') => $value); # = 4.1
validate (parameter => less_equal (4 => 'Float') => $value); # = 4.1
is_valid (parameter => l_e 4 => Int => $value); # = 3
my $value = 'Text';
is_valid (parameter => equal_to (text => String) => lc($value)); # compares as String
is_valid (parameter => equal_to (4 => String) => '4.0'); # not valid, compares as String
is_valid (parameter => equal_to (4 => Float) => 4.0); # valid, compares as number
is_valid (parameter => equal_to (4 => Int) => 4.0); # valid !!, compares as number
my $animal = par is_a Animal => shift;
my $person = par is_a (Person => shift);
my $tree = par is_a (Tree), shift;DESCRIPTION
This class implements a fast and flexible validation for scalars. It is implemented functional to get speed and some problems using global rules for all ;).
Possibly I started a reimplementation of Type::Params. I'm just checking the differences.
Validate Subs
Following validation functions exist:
validate(...);
par(...); # Alias for validate()
parameter(...); # Alias for validate()
named_parameter(...);
n_par(...); # Alias for named_parameter()
is_valid(...);validate(), parameter() and par()
Different names for same functionality. Use like
my $var_float = validate ('PI is a float' => Float => $PI);
my $par_int = par (par_int => Int => shift);First argument is a free name of the check done. If used as parameter check for subs it is the 'name' of the parameter.
Last argument holds the value to be checked. It has to be a scalar, and therefore the module was named Scalar::Validation.
Optional last argument: After the value argument can be added a sub to print out an own error message instead of the default error message:
my $var_float = validate ('PI is a float' => Float => $PI => sub { 'wrong defined $PI: '.$_ } );All parameters after first before value argument are used to select or define "validation rules": 'Float' and 'Int' in this example.
named_parameter(), n_par()
These subs extract named parameters out of a parameter_hash_ref. Key and value will be deleted from hash during validation. After processing all parameters hash_ref should be empty.
my $par_1_int = npar (par_1 => Int => \%parameters);
my $par_2_float = named_parameter (par_2 => Float => \%parameters);First argument ($key) is the key of the parameter. Last argument ($parameters) has to be a hash_ref.
Without these subs you would have to implement for reading par_1:
my $key = 'par_1';
my $value = delete $parameters->{$key};
my $par_1_int = par ($key => Int => $value);It could be done in one line, but this line will be complicated and not easy to understand. The key value is needed twice and that can cause Copy-Paste-Errors.
Dies by error message
On default, application dies with error message, if data checked by named_parameter(...) or validate(...) is not valid.
validate (parameter => -And => [Scalar => 'Int'], {} );
validate (parameter => -And => [Scalar => 'Int'], [] );
validate (parameter => -And => [Scalar => 'Int'], sub { 'abc'; });Just check without die
is_valid(...) just does validation and returns 1 in case on success and 0 in case of fail.
print is_valid(parameter => -And => [Scalar => 'Int'], 123) ." => 123 is int\n";
print is_valid(parameter => -And => [Scalar => 'Int'], {} ) ." => {} is no scalar\n";
print is_valid(parameter => -And => [Scalar => 'Int'], [] ) ." => [] is no scalar\n";
print is_valid(parameter => -And => [Scalar => 'Int'], sub { 'abc'; }) ." => sub { 'abc'; } is no scalar\n";Avoid trouble using invalid data
If a validation fails and validation mode is not set as 'die', you probably will run in trouble afterwards, when you use invalid data.
Therefore do
local ($Scalar::Validation::trouble_level) = 0;
# add your code
return undef if validation_trouble(); # fire exit, if validation does not dieor something similar.
is_valid(...) does not rise $trouble_level, as to be expected. All other validation subs do!
Get validation messages
Per default, no messages are stored to increase performance. To store messages, the message store has to be localized into an array_ref.
This is the only safe way to deal with recursive calls and die! So use a block like this to store messages
my @messages;
{
local ($Scalar::Validation::message_store) = [];
my $result = is_valid(parameter => -And => [Scalar => 'Int'], {} );
@messages = @{validation_messages()} unless $result;
}As parameter check for indexed arguments
Scalar::Validation can be also used a parameter check for unnamed and named parameters. parameters_end \@_; ensures, that all parameters are processed. Otherwise it rises the usual validation error. Shorthand: p_end.
sub create_some_polynom {
local ($Scalar::Validation::trouble_level) = 0;
my $max_potenz = par maximum_potenz => -Range => [1,5] => Int => shift;
# additional parameters ...
p_end \@_;
return undef if validation_trouble(); # fire exit, if validation does not die
# --- run sub -------------------------------------------------
my $polynom = '';
map { $polynom .= " + ".int (100*rand())."*x^".($max_potenz-$_); } (0..$max_potenz);
return $polynom;
};
print create_some_polynom(1)."\n";
print create_some_polynom(2)."\n";
print create_some_polynom(3)."\n";
print create_some_polynom(4)."\n";
print create_some_polynom(5)."\n";Dies by error message
print create_some_polynom("four")."\n";
print create_some_polynom(5.5)."\n";
print create_some_polynom(6)."\n";
print create_some_polynom(6, 1)."\n";As parameter check for named arguments
Named arguments can also be handled. This needs more runtime than the indexed variant.
convert_to_named_params() does a safe conversion by validate().
sub create_some_polynom_named {
local ($Scalar::Validation::trouble_level) = 0;
my %pars = convert_to_named_params \@_;
my $max_potenz = npar -maximum_potenz => -Range => [1,5] => Int => \%pars;
# additional parameters ...
parameters_end \%pars;
return undef if validation_trouble(); # fire exit, if validation does not die
# --- run sub -------------------------------------------------
my $polynom = '';
map { $polynom .= " + ".int (100*rand())."*x^".($max_potenz-$_); } (0..$max_potenz);
return $polynom;
};
print create_some_polynom_named(-maximum_potenz => 4);Rules
declare_rule(...)
You can and should create your own rules, i.e.
declare_rule (
Positive => -as => Int => # Parent rule is optional
-where => sub { $_ >= 0 },
-message => sub { "value $_ is not a positive integer" },
);
rule_known(Unknown => 1); # returns 0 (false)
rule_known(Positive => 1); # returns 1 (true)The value to be validated is stored in variable $_. For
-message => sub { "my message for wrong value $_."}it is enclosed in single ticks, so that you get the following output for $_ = "Garfield":
my message for wrong value 'Garfield'.delete_rule(...)
deletes_rule($rule) deletes rule $rule. It calls current validation fail method, if $rule not set or rule cannot be found.
delete_rule ('NegativeInt');replace_rule(...)
replace_rule($rule = ...)> deletes rule $rule first and then declares it. Same arguments as for declare_rule;
replace_rule (
NegativeInt => -as => Int => # Parent rule is optional
-where => sub { $_ =< 0 },
-message => sub { "value $_ is not a negative integer or 0" },
);Special Rules
There are some special rules, that cannot be changed. Those rules start with an '-' char in front:
-Optional # value may be undefined. If not, use following rule
-And # all rules must be ok
-Or # at least one rule must be ok
-Enum # for easy defining enumeration on the fly, by array_ref or hash_ref
-Range # Intervall: [start, end] => type
-RefEmpty # array_ref: scalar (@$array_ref) == 0
# hash_ref: scalar (keys %$hash_ref) == 0Reason is, that they combine other rules or have more or different parameters than a "normal" rule or using own implementation just to speed up.
All normal rules should not start with a '-', but it is not forbidden to do so.
my $var_float = validate ('PI is a float' => -Optional => Float => $PI => sub { 'wrong defined $PI: '.$_ } );This rule does not die, if $PI is undef because of -Optional in front.
Create Own Validation Module
You should not use Scalar::Validation direct in your code.
Better is creating an own module My::Validation, that adds the rules you need and only exports the subs the developers in your project should use:
use My::Validation;
my $v = validate v => my_type => new MyType();Dealing with XSD
In this case My::Validation should create rules out of XML datatypes after reading in a XSD file. So rules are dynamic and your application can handle different XSD definitions without knowing something about XSD outside of this module.
Also you can filter XSD type contents, i.e. for enmuerations: Allowing not all possible values in UI or remove entries only for compatibility with old versions.
And your Application or GUI doesn't need to know about it.
Validation Modes
There are 4 predefined validation modes:
die
warn
silent
offis_valid()
is_valid() uses a special validation mode independent from the followings. It will do the checks in all cases except mode 'off'.
Validation Mode 'die' (default)
The validation methods call croak "validation message"; in case of failures or a rule fails. Your script (or this part of your script) will die.
Validation Mode 'warn'
The validation methods call carp "validation message"; in case of failures or a rule fails. Your get warnings for every failed rule.
Your script (or this part of your script) will NOT die.
It will continue work. In critical cases you should take care, that process will be stopped: Use validation_trouble()!
Validation Mode 'silent'
The validation methods just store messages, if there is a message store available. No messages will be printed out.
Your script (or this part of your script) will NOT die.
It will continue work. In critical cases you should take care, that process will be stopped: Use validation_trouble()!
Validation Mode 'off'
The validation methods just give back the value. They even don't process the call parameters of the validation routines.
is_valid() is also turned off and returns 1 for all calls.
Be careful! Now you are playing with dynamite! But you are fast. If you explode, just try switch validation on, if you are still alive.
Faster than Validation Mode 'off'
Remove validation calls
Remove all validation calls from your code and fall back to era before Scalar::Validation.
Be careful! Now you are playing with nitroglycerin! But you cannot be faster.
Duplicate parameter management
Having two parameter managements, switch between them by testing $Scalar::Validation::off:
sub create_some_polynom {
my ($max_potenz,
) = @_;
if ($Scalar::Validation::off) {
local ($Scalar::Validation::trouble_level) = 0;
$max_potenz = par maximum_potenz => -Range => [1,5] => Int => shift;
# additional parameters ...
p_end \@_;
return undef if validation_trouble(); # fire exit, if validation does not die
}
# --- run sub -------------------------------------------------
my $polynom = '';
map { $polynom .= " + ".int (100*rand())."*x^".($max_potenz-$_); } (0..$max_potenz);
return $polynom;
};Now you have only one extra if statement compared to version without checks. But you have duplicate parameter management. So only choose this variant if performance is a real problem for your sub.
Be careful! You are still playing with dynamite! But you are fast. If you explode, just try switch validation on, if you are still alive.
Traps
my $unvalidated = par => value => Int => shift; # value is just used without checking
my $string_shift = par value => Int => shift => sub { "$_ is still 'shift!!'. Why?"};par => value
my $unvalidated = par => value => Int => shift; # value is just used without checkingpar, npar, validate, ... are functions, not keywords. The mistake here is to use " => " instead of ",". Why? The special comma operator quotes the left argument of
par => valueso you get
'par', valueand now par is a string and not a function. You get the last value of the list, and that is shift! NO VALIDATION! So don't forget to write tests with invalid data to detect this trap.
By using brackets
my $unvalidated = par (value => Int => shift);you avoid this trap.
shift => sub { ... }
Another trap
my $string_shift = par value => Int => shift => sub { "$_ is still 'shift!!'. Why?"};The mistake here is also to use " => " instead of ","
shift => sub { }It will be interpreted as
'shift', sub { }and so you get constant string 'shift' instead of the next value from parameter stack.
Or if both traps are combined, you get the last argument, that may be a coderef.
You cannot avoid this trap by safe coding, but it will be easy detected by unit testing.
More Examples
Have a look into the examples directory or Scalar-Validation.t to see what else is possible.
Comming Soon
if_par()
if_par sets value only, if matching to rule. Otherwise returns undef.
my $file_option = if_par_named (-file => Defined => \%options);or
my $file_option = if_par_indexed (file => Defined => shift);
my $file_name = if_par (file => FileName => $file_option);
my $file_handle = if_par (file => FileHandle => $file_option);
if_par_end $file_option; # raises $trouble_level if $file_option is not EmptyBoth $file_name and $file_handle, one or none can be set, that depends on the rules.
$file_option is a hash containing keys -value, -matched (counter), -rules (string of all tried).
if_par_end checks that at least one rule fits.
Comming Later
Generating documentation out source using special implementations of
named_parameter
parameter
parameters_endSEE ALSO Moose, Moo and Type::Params
Use Moose if possible. If not possible, have a look to Moo and Type::Params.
Possible reimplementation of Type::Params
Possibly I started a reimplementation of Type::Params. I'm just checking the differences.
LICENSE AND COPYRIGHT
Copyright (c) 2014 by Ralf Peine, Germany. All rights reserved.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.6.0 or, at your option, any later version of Perl 5 you may have available.
DISCLAIMER OF WARRANTY
This library is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.
1 POD Error
The following errors were encountered while parsing the POD:
- Around line 1038:
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