1 files changed, 36 insertions, 0 deletions
diff --git a/src/error.rs b/src/error.rs
index bcee4ff..31fca60 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -334,3 +334,39 @@ impl SubplotError {
 
 /// A result type for this crate.
 pub type Result<T> = std::result::Result<T, SubplotError>;
+
+/// A warning, or non-fatal error.
+///
+/// Errors prevent Subplot from producing output. Warnings don't do that.
+#[derive(Debug)]
+pub enum Warning {
+    /// Document refers to an embedded file that doesn't exist.
+    UnknownEmbeddedFile(String),
+
+    /// Embedded file is not used by any scenario.
+    UnusedEmbeddedFile(String),
+
+    /// Missing step implementation.
+    MissingStepImplementation(String),
+}
+
+/// A list of warnings.
+///
+/// Subplot collects warnings into this structure so that they can be
+/// processed at the end.
+#[derive(Debug, Default)]
+pub struct Warnings {
+    warnings: Vec<Warning>,
+}
+
+impl Warnings {
+    /// Append a warning to the list.
+    pub fn push(&mut self, w: Warning) {
+        self.warnings.push(w);
+    }
+
+    /// Return a slice with all the warnings in the list.
+    pub fn warnings(&self) -> &[Warning] {
+        &self.warnings
+    }
+}