errors: Add error case for regex metacharacters detected

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/error.rs b/src/error.rs
index 53128b2..60c850e 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -10,6 +10,14 @@ pub enum SubplotError {
     #[error("simple pattern contains a stray {{ or }}")]
     StrayBraceInSimplePattern(String),
 
+    /// The simple pattern has regex metacharacters.
+    ///
+    /// Simple patterns are not permitted to have regex metacharacters in them
+    /// unless the pattern is explicitly marked `regex: false` to indicate that
+    /// the binding author understands what they're up to.
+    #[error("simple pattern contains regex metacharacters: {0}")]
+    SimplePatternHasMetaCharacters(String),
+
     /// Scenario step does not match a known binding
     ///
     /// This may be due to the binding missing entirely, or that the