1 files changed, 55 insertions, 0 deletions
diff --git a/third_party/rust/litrs/src/bool/mod.rs b/third_party/rust/litrs/src/bool/mod.rs
new file mode 100644
index 0000000000..d7b54a1b9f
--- /dev/null
+++ b/third_party/rust/litrs/src/bool/mod.rs
@@ -0,0 +1,55 @@
+use std::fmt;
+
+use crate::{ParseError, err::{perr, ParseErrorKind::*}};
+
+
+/// A bool literal: `true` or `false`. Also see [the reference][ref].
+///
+/// Notice that, strictly speaking, from Rust point of view "boolean literals" are not
+/// actual literals but [keywords].
+///
+/// [ref]: https://doc.rust-lang.org/reference/expressions/literal-expr.html#boolean-literal-expressions
+/// [keywords]: https://doc.rust-lang.org/reference/keywords.html#strict-keywords
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum BoolLit {
+    False,
+    True,
+}
+
+impl BoolLit {
+    /// Parses the input as a bool literal. Returns an error if the input is
+    /// invalid or represents a different kind of literal.
+    pub fn parse(s: &str) -> Result<Self, ParseError> {
+        match s {
+            "false" => Ok(Self::False),
+            "true" => Ok(Self::True),
+            _ => Err(perr(None, InvalidLiteral)),
+        }
+    }
+
+    /// Returns the actual Boolean value of this literal.
+    pub fn value(self) -> bool {
+        match self {
+            Self::False => false,
+            Self::True => true,
+        }
+    }
+
+    /// Returns the literal as string.
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::False => "false",
+            Self::True => "true",
+        }
+    }
+}
+
+impl fmt::Display for BoolLit {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.pad(self.as_str())
+    }
+}
+
+
+#[cfg(test)]
+mod tests;