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move some of the Validators to an ExtraValidators file (#1192)

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Rework some of the validator locations, add documentation, and fix some
lingering issues with validators.
The extra will will enable additions of some new validators and reduce
compile times for those that are not needed.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
This commit is contained in:
Philip Top
2025-09-01 05:13:21 -07:00
committed by GitHub
parent 1ab8646760
commit 8c77664bd0
37 changed files with 1823 additions and 1229 deletions
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147
book/chapters/validators.md
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@@ -71,6 +71,15 @@ The built-in validators for CLI11 are:
| `ExistingPath` | Check for an existing path |
| `NonexistentPath` | Check for an non-existing path |
| `Range(min=0, max)` | Produce a range (factory). Min and max are inclusive. |
| `NonNegativeNumber` | Range(0,max<double>) |
| `PositiveNumber` | Range(epsilon,max<double>) |
A few built-in transformers are also available
| Transformer | Description |
| ------------------- | ---------------------------------------------------------- |
| `EscapedString` | modify a string using defined escape characters |
| `FileOnDefaultPath` | Modify a path if the file is a particular default location |
And, the protected members that you can set when you make your own are:
@@ -82,3 +91,141 @@ And, the protected members that you can set when you make your own are:
| `int` (`-1`) | `application_index_` | The element this validator applies to (-1 for all) |
| `bool` (`true`) | `active_` | This can be disabled |
| `bool` (`false`) | `non_modifying_` | Specify that this is a Validator instead of a Transformer |
## Extra Validators
Until CLI11 v3.0 these validators will be available by default. They can be
disabled at compilation time by defining CLI11_DISABLE_EXTRA_VALIDATORS to 1.
After version 3.0 they can be enabled by defining CLI11_ENABLE_EXTRA_VALIDATORS
to 1. Some of the Validators are template heavy so if they are not needed and
compilation time is a concern they can be disabled.
| Validator | Description |
| -------------------- | ------------------------------------------------------------------ |
| `ValidIPV4` | check for valid IPV4 address XX.XX.XX.XX |
| `TypeValidator<T>` | template for checking that a value can convert to a specific type |
| `Number` | Check that a value can convert to a number |
| `IsMember` | Check that a value is one of a set of values |
| `CheckedTransformer` | Values must be one of the transformed set or the result |
| `AsNumberWithUnit` | checks for numbers with a unit as part of a specified set of units |
| `AsSizeValue` | As Number with Unit with support for SI prefixes |
| Transformer | Description |
| ---------------------- | --------------------------------------------------- |
| `Bound<T>(min=0, max)` | Force a range (factory). Min and max are inclusive. |
| `Transformer` | Modify values in a set to the matching pair value |
## New Extra Validators
Some additional validators can be enabled by using CLI11_ENABLE_EXTRA_VALIDATORS
to 1. These validators are disabled by default.
## Custom Validators
CLI11 also supports the use of custom validators, this includes using the
Validator class constructor with a custom function calls or subclassing
Validator to define a new class.
### Custom Validator operation
The simplest way to make a new Validator is to mimic how many of the existing
Validators are created. Take for example the `IPV4Validator`
```cpp
class IPV4Validator : public Validator {
public:
IPV4Validator();
};
CLI11_INLINE IPV4Validator::IPV4Validator() : Validator("IPV4") {
func_ = [](std::string &ip_addr) {
auto cdot = std::count(ip_addr.begin(), ip_addr.end(), '.');
if(cdot != 3u) {
return std::string("Invalid IPV4 address: must have 3 separators");
}
auto result = CLI::detail::split(ip_addr, '.');
if(result.size() != 4) {
return std::string("Invalid IPV4 address: must have four parts (") + ip_addr + ')';
}
int num = 0;
for(const auto &var : result) {
using CLI::detail::lexical_cast;
bool retval = lexical_cast(var, num);
if(!retval) {
return std::string("Failed parsing number (") + var + ')';
}
if(num < 0 || num > 255) {
return std::string("Each IP number must be between 0 and 255 ") + var;
}
}
return std::string{};
};
}
```
The `IPV4Validator` class inherits from `Validator` and creates a new
constructor. In that constructor it defines the lambda function that does the
checking. Then IPV4 can be used like any other Validator. One specific item of
note is that the class does not define any new member variables, so the class if
copyable to a Validator, only the constructor is different.
If additional members are needed, then the `check` and `transform` overloads
that use shared pointers need to be used. The other overloads pass by value so
polymorphism doesn't work. The custom_validator example shows a case like this.
```cpp
template <typename T> class DeltaRange : public CLI::Validator {
public:
T center_point;
T delta;
DeltaRange(const T &center, const T &range)
: CLI::Validator(
[this](const std::string &value) -> std::string {
T newValue;
auto result = CLI::detail::lexical_cast(value, newValue);
if(!(result && this->check(newValue))) {
return std::string("value not within range");
}
return std::string{};
},
"RANGE"),
center_point(center), delta(range) {}
CLI11_NODISCARD bool check(const T &test) const { return (test >= (center_point - delta)) && (test <= (center_point + delta)); }
CLI11_NODISCARD T center() const { return center_point; }
CLI11_NODISCARD T range() const { return delta; }
void center(const T &value) { center_point = value; }
void range(const T &value) { delta = value; }
};
int main(int argc, char **argv) {
/* this application creates custom validator which is a range center+/- range The center and range can be defined by
* other command line options and are updated dynamically
*/
CLI::App app("custom range validator");
std::string value;
auto dr = std::make_shared<DeltaRange<int>>(7, 3);
app.add_option("--number", value, "enter value in the related range")->check(dr)->required();
app.add_option_function<int>("--center", [&dr](int new_center) { dr->center(new_center); })->trigger_on_parse();
app.add_option_function<int>("--range", [&dr](int new_range) { dr->range(new_range); })->trigger_on_parse();
CLI11_PARSE(app, argc, argv);
std::cout << "number " << value << " in range = " << dr->center() << " +/- " << dr->range() << '\n';
return 0;
}
```
The Validator defines some new operations, and in the use case the Validator is
constructed using shared_ptrs. This allows polymorphism to work and the
Validator instance to be shared across multiple options, and as in this example
adapted during the parsing and checking.
There are a few limitation in this, single instances should not be used with
both transform and check. Check modifies some flags in the Validator to prevent
value modification, so that would prevent its use as a transform. Which could be
user modified later but that would potentially allow the check to modify the
value unintentionally.