More utility functions

- join("a", "b", "c", sep: ", ")
- int("12")
- float("31.4e-1")
- str(10)
- sorted((3, 2, 1))

5 files changed, 62 insertions, 3 deletions

diff --git a/src/eval/array.rs b/src/eval/array.rs
index acf44ab2..bae89c4b 100644
--- a/src/eval/array.rs
+++ b/src/eval/array.rs
@@ -1,3 +1,4 @@
+use std::cmp::Ordering;
 use std::convert::TryFrom;
 use std::fmt::{self, Debug, Display, Formatter, Write};
 use std::iter::FromIterator;
@@ -80,6 +81,26 @@ impl Array {
         self.0.iter()
     }
 
+    /// Return a sorted version of this array.
+    ///
+    /// Returns an error if two values could not be compared.
+    pub fn sorted(mut self) -> StrResult<Self> {
+        let mut result = Ok(());
+        Rc::make_mut(&mut self.0).sort_by(|a, b| {
+            a.partial_cmp(b).unwrap_or_else(|| {
+                if result.is_ok() {
+                    result = Err(format!(
+                        "cannot compare {} with {}",
+                        a.type_name(),
+                        b.type_name(),
+                    ));
+                }
+                Ordering::Equal
+            })
+        });
+        result.map(|_| self)
+    }
+
     /// Repeat this array `n` times.
     pub fn repeat(&self, n: i64) -> StrResult<Self> {
         let count = usize::try_from(n)
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index b8561a87..f48312c8 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -5,13 +5,14 @@ mod array;
 #[macro_use]
 mod dict;
 #[macro_use]
+mod str;
+#[macro_use]
 mod value;
 mod capture;
 mod function;
 mod ops;
 mod scope;
 mod state;
-mod str;
 mod template;
 mod walk;
 
diff --git a/src/eval/ops.rs b/src/eval/ops.rs
index 6d34b877..c7a45614 100644
--- a/src/eval/ops.rs
+++ b/src/eval/ops.rs
@@ -291,12 +291,21 @@ pub fn compare(lhs: &Value, rhs: &Value) -> Option<Ordering> {
     match (lhs, rhs) {
         (Bool(a), Bool(b)) => a.partial_cmp(b),
         (Int(a), Int(b)) => a.partial_cmp(b),
-        (Int(a), Float(b)) => (*a as f64).partial_cmp(b),
-        (Float(a), Int(b)) => a.partial_cmp(&(*b as f64)),
         (Float(a), Float(b)) => a.partial_cmp(b),
         (Angle(a), Angle(b)) => a.partial_cmp(b),
         (Length(a), Length(b)) => a.partial_cmp(b),
+        (Relative(a), Relative(b)) => a.partial_cmp(b),
+        (Fractional(a), Fractional(b)) => a.partial_cmp(b),
         (Str(a), Str(b)) => a.partial_cmp(b),
+
+        // Some technically different things should be comparable.
+        (&Int(a), &Float(b)) => (a as f64).partial_cmp(&b),
+        (&Float(a), &Int(b)) => a.partial_cmp(&(b as f64)),
+        (&Length(a), &Linear(b)) if b.rel.is_zero() => a.partial_cmp(&b.abs),
+        (&Relative(a), &Linear(b)) if b.abs.is_zero() => a.partial_cmp(&b.rel),
+        (&Linear(a), &Length(b)) if a.rel.is_zero() => a.abs.partial_cmp(&b),
+        (&Linear(a), &Relative(b)) if a.abs.is_zero() => a.rel.partial_cmp(&b),
+
         _ => Option::None,
     }
 }
diff --git a/src/eval/str.rs b/src/eval/str.rs
index a358cd9f..099a4363 100644
--- a/src/eval/str.rs
+++ b/src/eval/str.rs
@@ -1,3 +1,4 @@
+use std::borrow::Borrow;
 use std::convert::TryFrom;
 use std::fmt::{self, Debug, Display, Formatter, Write};
 use std::ops::{Add, AddAssign, Deref};
@@ -5,6 +6,16 @@ use std::ops::{Add, AddAssign, Deref};
 use crate::diag::StrResult;
 use crate::util::EcoString;
 
+/// Create a new [`Str`] from a format string.
+macro_rules! format_str {
+    ($($tts:tt)*) => {{
+        use std::fmt::Write;
+        let mut s = $crate::util::EcoString::new();
+        write!(s, $($tts)*).unwrap();
+        $crate::eval::Str::from(s)
+    }};
+}
+
 /// A string value with inline storage and clone-on-write semantics.
 #[derive(Default, Clone, Eq, PartialEq, Ord, PartialOrd)]
 pub struct Str(EcoString);
@@ -92,6 +103,18 @@ impl AddAssign for Str {
     }
 }
 
+impl AsRef<str> for Str {
+    fn as_ref(&self) -> &str {
+        self
+    }
+}
+
+impl Borrow<str> for Str {
+    fn borrow(&self) -> &str {
+        self
+    }
+}
+
 impl From<char> for Str {
     fn from(c: char) -> Self {
         Self(c.into())
diff --git a/src/eval/value.rs b/src/eval/value.rs
index 5edf0362..77cb766c 100644
--- a/src/eval/value.rs
+++ b/src/eval/value.rs
@@ -88,6 +88,11 @@ impl Value {
     {
         T::cast(self)
     }
+
+    /// Join the value with another value.
+    pub fn join(self, rhs: Self) -> StrResult<Self> {
+        ops::join(self, rhs)
+    }
 }
 
 impl Default for Value {