Add isize filter
@@ -10,6 +10,8 @@ mod json;
#[cfg(feature = "serde-json")]
pub use self::json::json;
+use error::Error::Fmt;
+use num_traits::cast::NumCast;
use num_traits::Signed;
use std::fmt;
@@ -20,7 +22,7 @@ use escaping::{self, MarkupDisplay};
// Askama or should refer to a local `filters` module. It should contain all the
// filters shipped with Askama, even the optional ones (since optional inclusion
// in the const vector based on features seems impossible right now).
-pub const BUILT_IN_FILTERS: [&str; 19] = [
+pub const BUILT_IN_FILTERS: [&str; 20] = [
"abs",
"capitalize",
"center",
@@ -28,6 +30,7 @@ pub const BUILT_IN_FILTERS: [&str; 19] = [
"escape",
"format",
"indent",
+ "into_isize",
"join",
"linebreaks",
"linebreaksbr",
@@ -158,6 +161,14 @@ pub fn indent(s: &fmt::Display, width: &usize) -> Result<String> {
Ok(indented)
}
+/// Casts number to isize
+pub fn into_isize<T>(number: T) -> Result<isize>
+where
+ T: NumCast,
+{
+ number.to_isize().ok_or(Fmt(fmt::Error))
+}
+
/// Joins iterable into a string separated by provided argument
pub fn join<T, I, S>(input: I, separator: S) -> Result<String>
where
@@ -246,6 +257,7 @@ pub fn wordcount(s: &fmt::Display) -> Result<usize> {
#[cfg(test)]
mod tests {
use super::*;
+ use std::f64::INFINITY;
#[test]
fn test_linebreaks() {
@@ -300,6 +312,19 @@ mod tests {
);
}
+ #[test]
+ fn test_into_isize() {
+ assert_eq!(into_isize(1).unwrap(), 1 as isize);
+ assert_eq!(into_isize(1.9).unwrap(), 1 as isize);
+ assert_eq!(into_isize(-1.9).unwrap(), -1 as isize);
+ assert_eq!(into_isize(1.5 as f64).unwrap(), 1 as isize);
+ assert_eq!(into_isize(-1.5 as f64).unwrap(), -1 as isize);
+ match into_isize(INFINITY) {
+ Err(Fmt(fmt::Error)) => assert!(true),
+ _ => assert!(false, "Should return error of type Err(Fmt(fmt::Error))"),
+ };
+ }
+
#[test]
fn test_join() {
assert_eq!(
