minijinja/tests.rs
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//! Test functions and abstractions.
//!
//! Test functions in MiniJinja are like [`filters`](crate::filters) but a
//! different syntax is used to invoke them and they have to return boolean
//! values. For instance the expression `{% if foo is defined %}` invokes the
//! [`is_defined`] test to check if the value is indeed an odd number.
//!
//! MiniJinja comes with some built-in test functions that are listed below. To
//! create a custom test write a function that takes at least a value argument
//! that returns a boolean result, then register it with
//! [`add_filter`](crate::Environment::add_test).
//!
//! # Using Tests
//!
//! Tests are useful to "test" a value in a specific way. For instance if
//! you want to assign different classes to alternating rows one way is
//! using the `odd` test:
//!
//! ```jinja
//! {% if seq is defined %}
//! <ul>
//! {% for item in seq %}
//! <li class="{{ 'even' if loop.index is even else 'odd' }}">{{ item }}</li>
//! {% endfor %}
//! </ul>
//! {% endif %}
//! ```
//!
//! # Custom Tests
//!
//! A custom test function is just a simple function which accepts its
//! inputs as parameters and then returns a bool. For instance the following
//! shows a test function which takes an input value and checks if it's
//! lowercase:
//!
//! ```
//! # use minijinja::Environment;
//! # let mut env = Environment::new();
//! fn is_lowercase(value: String) -> bool {
//! value.chars().all(|x| x.is_lowercase())
//! }
//!
//! env.add_test("lowercase", is_lowercase);
//! ```
//!
//! MiniJinja will perform the necessary conversions automatically. For more
//! information see the [`Test`] trait.
//!
//! # Built-in Tests
//!
//! When the `builtins` feature is enabled a range of built-in tests are
//! automatically added to the environment. These are also all provided in
//! this module. Note though that these functions are not to be
//! called from Rust code as their exact interface (arguments and return types)
//! might change from one MiniJinja version to another.
use std::sync::Arc;
use crate::error::Error;
use crate::utils::SealedMarker;
use crate::value::{ArgType, FunctionArgs, Value};
use crate::vm::State;
type TestFunc = dyn Fn(&State, &[Value]) -> Result<bool, Error> + Sync + Send + 'static;
#[derive(Clone)]
pub(crate) struct BoxedTest(Arc<TestFunc>);
/// A utility trait that represents the return value of filters.
///
/// It's implemented for the following types:
///
/// * `bool`
/// * `Result<bool, Error>`
///
/// The equivalent for filters or functions is [`FunctionResult`](crate::value::FunctionResult).
pub trait TestResult {
#[doc(hidden)]
fn into_result(self) -> Result<bool, Error>;
}
impl TestResult for Result<bool, Error> {
fn into_result(self) -> Result<bool, Error> {
self
}
}
impl TestResult for bool {
fn into_result(self) -> Result<bool, Error> {
Ok(self)
}
}
/// A utility trait that represents test functions.
///
/// This trait is used by the [`add_test`](crate::Environment::add_test) method to abstract over
/// different types of functions that implement tests. Tests are similar to
/// [`filters`](crate::filters) but they always return boolean values and use a
/// slightly different syntax to filters. Like filters they accept the [`State`] by
/// reference as first parameter and the value that that the test is applied to as second.
/// Additionally up to 4 further parameters are supported.
///
/// A test function can return any of the following types:
///
/// * `bool`
/// * `Result<bool, Error>`
///
/// Tests accept one mandatory parameter which is the value the filter is
/// applied to and up to 4 extra parameters. The extra parameters can be
/// marked optional by using `Option<T>`. The last argument can also use
/// [`Rest<T>`](crate::value::Rest) to capture the remaining arguments. All
/// types are supported for which [`ArgType`] is implemented.
///
/// For a list of built-in tests see [`tests`](crate::tests).
///
/// # Basic Example
///
/// ```
/// # use minijinja::Environment;
/// # let mut env = Environment::new();
/// use minijinja::State;
///
/// fn is_lowercase(value: String) -> bool {
/// value.chars().all(|x| x.is_lowercase())
/// }
///
/// env.add_test("lowercase", is_lowercase);
/// ```
///
/// ```jinja
/// {{ "foo" is lowercase }} -> true
/// ```
///
/// # Arguments and Optional Arguments
///
/// ```
/// # use minijinja::Environment;
/// # let mut env = Environment::new();
/// use minijinja::State;
///
/// fn is_containing(value: String, other: String) -> bool {
/// value.contains(&other)
/// }
///
/// env.add_test("containing", is_containing);
/// ```
///
/// ```jinja
/// {{ "foo" is containing("o") }} -> true
/// ```
pub trait Test<Rv, Args>: Send + Sync + 'static {
/// Performs a test to value with the given arguments.
#[doc(hidden)]
fn perform(&self, args: Args, _: SealedMarker) -> Rv;
}
macro_rules! tuple_impls {
( $( $name:ident )* ) => {
impl<Func, Rv, $($name),*> Test<Rv, ($($name,)*)> for Func
where
Func: Fn($($name),*) -> Rv + Send + Sync + 'static,
Rv: TestResult,
$($name: for<'a> ArgType<'a>),*
{
fn perform(&self, args: ($($name,)*), _: SealedMarker) -> Rv {
#[allow(non_snake_case)]
let ($($name,)*) = args;
(self)($($name,)*)
}
}
};
}
tuple_impls! {}
tuple_impls! { A }
tuple_impls! { A B }
tuple_impls! { A B C }
tuple_impls! { A B C D }
tuple_impls! { A B C D E }
impl BoxedTest {
/// Creates a new boxed filter.
pub fn new<F, Rv, Args>(f: F) -> BoxedTest
where
F: Test<Rv, Args> + for<'a> Test<Rv, <Args as FunctionArgs<'a>>::Output>,
Rv: TestResult,
Args: for<'a> FunctionArgs<'a>,
{
BoxedTest(Arc::new(move |state, args| -> Result<bool, Error> {
f.perform(ok!(Args::from_values(Some(state), args)), SealedMarker)
.into_result()
}))
}
/// Applies the filter to a value and argument.
pub fn perform(&self, state: &State, args: &[Value]) -> Result<bool, Error> {
(self.0)(state, args)
}
}
/// Checks if a value is undefined.
///
/// ```jinja
/// {{ 42 is undefined }} -> false
/// ```
pub fn is_undefined(v: Value) -> bool {
v.is_undefined()
}
/// Checks if a value is defined.
///
/// ```jinja
/// {{ 42 is defined }} -> true
/// ```
pub fn is_defined(v: Value) -> bool {
!v.is_undefined()
}
/// Checks if a value is none.
///
/// ```jinja
/// {{ none is none }} -> true
/// ```
pub fn is_none(v: Value) -> bool {
v.is_none()
}
/// Checks if a value is safe.
///
/// ```jinja
/// {{ "<hello>"|escape is safe }} -> true
/// ```
///
/// This filter is also registered with the `escaped` alias.
pub fn is_safe(v: Value) -> bool {
v.is_safe()
}
#[cfg(feature = "builtins")]
mod builtins {
use super::*;
use std::borrow::Cow;
use crate::value::ops::{coerce, CoerceResult};
use crate::value::ValueKind;
/// Return true if the object is a boolean value.
///
/// ```jinja
/// {{ true is boolean }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_boolean(v: Value) -> bool {
v.kind() == ValueKind::Bool
}
/// Checks if a value is odd.
///
/// ```jinja
/// {{ 41 is odd }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_odd(v: Value) -> bool {
i128::try_from(v).ok().map_or(false, |x| x % 2 != 0)
}
/// Checks if a value is even.
///
/// ```jinja
/// {{ 42 is even }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_even(v: Value) -> bool {
i128::try_from(v).ok().map_or(false, |x| x % 2 == 0)
}
/// Return true if the value is divisible by another one.
///
/// ```jinja
/// {{ 42 is divisibleby(2) }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_divisibleby(v: Value, other: Value) -> bool {
match coerce(&v, &other, false) {
Some(CoerceResult::I128(a, b)) => (a % b) == 0,
Some(CoerceResult::F64(a, b)) => (a % b) == 0.0,
_ => false,
}
}
/// Checks if this value is a number.
///
/// ```jinja
/// {{ 42 is number }} -> true
/// {{ "42" is number }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_number(v: Value) -> bool {
matches!(v.kind(), ValueKind::Number)
}
/// Checks if this value is an integer.
///
/// ```jinja
/// {{ 42 is integer }} -> true
/// {{ 42.0 is integer }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_integer(v: Value) -> bool {
v.is_integer()
}
/// Checks if this value is a float
///
/// ```jinja
/// {{ 42 is float }} -> false
/// {{ 42.0 is float }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_float(v: Value) -> bool {
matches!(v.0, crate::value::ValueRepr::F64(_))
}
/// Checks if this value is a string.
///
/// ```jinja
/// {{ "42" is string }} -> true
/// {{ 42 is string }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_string(v: Value) -> bool {
matches!(v.kind(), ValueKind::String)
}
/// Checks if this value is a sequence
///
/// ```jinja
/// {{ [1, 2, 3] is sequence }} -> true
/// {{ 42 is sequence }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_sequence(v: Value) -> bool {
matches!(v.kind(), ValueKind::Seq)
}
/// Checks if this value can be iterated over.
///
/// ```jinja
/// {{ [1, 2, 3] is iterable }} -> true
/// {{ 42 is iterable }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_iterable(v: Value) -> bool {
v.try_iter().is_ok()
}
/// Checks if this value is a mapping
///
/// ```jinja
/// {{ {"foo": "bar"} is mapping }} -> true
/// {{ [1, 2, 3] is mapping }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_mapping(v: Value) -> bool {
matches!(v.kind(), ValueKind::Map)
}
/// Checks if the value is starting with a string.
///
/// ```jinja
/// {{ "foobar" is startingwith "foo" }} -> true
/// {{ "foobar" is startingwith "bar" }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_startingwith(v: Cow<'_, str>, other: Cow<'_, str>) -> bool {
v.starts_with(&other as &str)
}
/// Checks if the value is ending with a string.
///
/// ```jinja
/// {{ "foobar" is endingwith "bar" }} -> true
/// {{ "foobar" is endingwith "foo" }} -> false
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
pub fn is_endingwith(v: Cow<'_, str>, other: Cow<'_, str>) -> bool {
v.ends_with(&other as &str)
}
/// Test version of `==`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 1 is eq 1 }} -> true
/// {{ [1, 2, 3]|select("==", 1) }} => [1]
/// ```
///
/// By default aliased to `equalto` and `==`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_eq(value: &Value, other: &Value) -> bool {
*value == *other
}
/// Test version of `!=`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 2 is ne 1 }} -> true
/// {{ [1, 2, 3]|select("!=", 1) }} => [2, 3]
/// ```
///
/// By default aliased to `!=`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_ne(value: &Value, other: &Value) -> bool {
*value != *other
}
/// Test version of `<`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 1 is lt 2 }} -> true
/// {{ [1, 2, 3]|select("<", 2) }} => [1]
/// ```
///
/// By default aliased to `lessthan` and `<`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_lt(value: &Value, other: &Value) -> bool {
*value < *other
}
/// Test version of `<=`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 1 is le 2 }} -> true
/// {{ [1, 2, 3]|select("<=", 2) }} => [1, 2]
/// ```
///
/// By default aliased to `<=`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_le(value: &Value, other: &Value) -> bool {
*value <= *other
}
/// Test version of `>`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 2 is gt 1 }} -> true
/// {{ [1, 2, 3]|select(">", 2) }} => [3]
/// ```
///
/// By default aliased to `greaterthan` and `>`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_gt(value: &Value, other: &Value) -> bool {
*value > *other
}
/// Test version of `>=`.
///
/// This is useful when combined with [`select`](crate::filters::select).
///
/// ```jinja
/// {{ 2 is ge 1 }} -> true
/// {{ [1, 2, 3]|select(">=", 2) }} => [2, 3]
/// ```
///
/// By default aliased to `>=`.
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_ge(value: &Value, other: &Value) -> bool {
*value >= *other
}
/// Test version of `in`.
///
/// ```jinja
/// {{ 1 is in [1, 2, 3] }} -> true
/// {{ [1, 2, 3]|select("in", [1, 2]) }} => [1, 2]
/// ```
///
/// This is useful when combined with [`select`](crate::filters::select).
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_in(state: &State, value: &Value, other: &Value) -> Result<bool, Error> {
ok!(state.undefined_behavior().assert_iterable(value));
Ok(crate::value::ops::contains(other, value)
.map(|value| value.is_true())
.unwrap_or(false))
}
/// Checks if a value is `true`.
///
/// ```jinja
/// {% if value is true %}...{% endif %}
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_true(value: &Value) -> bool {
matches!(value.0, crate::value::ValueRepr::Bool(true))
}
/// Checks if a value is `false`.
///
/// ```jinja
/// {% if value is false %}...{% endif %}
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_false(value: &Value) -> bool {
matches!(value.0, crate::value::ValueRepr::Bool(false))
}
/// Checks if a filter with a given name is available.
///
/// ```jinja
/// {% if 'tojson' is filter %}...{% endif %}
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_filter(state: &State, name: &str) -> bool {
state.env.get_filter(name).is_some()
}
/// Checks if a test with a given name is available.
///
/// ```jinja
/// {% if 'greaterthan' is test %}...{% endif %}
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_test(state: &State, name: &str) -> bool {
state.env.get_test(name).is_some()
}
/// Checks if a string is all lowercase.
///
/// ```jinja
/// {{ 'foo' is lower }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_lower(name: &str) -> bool {
name.chars().all(|x| x.is_lowercase())
}
/// Checks if a string is all uppercase.
///
/// ```jinja
/// {{ 'FOO' is upper }} -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_upper(name: &str) -> bool {
name.chars().all(|x| x.is_uppercase())
}
/// Checks if two values are identical.
///
/// This primarily exists for compatibilith with Jinja2. It can be seen as a much
/// stricter comparison than a regular comparison. The main difference is that
/// values that have the same structure but a different internal object will not
/// compare equal.
///
/// ```jinja
/// {{ [1, 2, 3] is sameas [1, 2, 3] }}
/// -> false
///
/// {{ false is sameas false }}
/// -> true
/// ```
#[cfg_attr(docsrs, doc(cfg(feature = "builtins")))]
#[cfg(feature = "builtins")]
pub fn is_sameas(value: &Value, other: &Value) -> bool {
match (value.as_object(), other.as_object()) {
(Some(a), Some(b)) => a.is_same_object(b),
(None, Some(_)) | (Some(_), None) => false,
(None, None) => {
if value.kind() != other.kind() || value.is_integer() != other.is_integer() {
false
} else {
value == other
}
}
}
}
}
#[cfg(feature = "builtins")]
pub use self::builtins::*;