From 0d01692c97ea8ca6fc4b229e5b9678cb252bceda Mon Sep 17 00:00:00 2001
From: Greg Brown <gmb60@cam.ac.uk>
Date: Sat, 9 Jan 2021 14:31:02 +0000
Subject: Introduce chomp as a procedural macro.

Add a bunch of tests.

Fix chomp and chewed so autochomp compiles.
---
 src/chomp/error.rs | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

(limited to 'src/chomp/error.rs')

diff --git a/src/chomp/error.rs b/src/chomp/error.rs
index ffcbdd0..e7e4660 100644
--- a/src/chomp/error.rs
+++ b/src/chomp/error.rs
@@ -358,6 +358,19 @@ pub enum SubstituteError {
     WrongArgCount { call: Call, expected: usize },
 }
 
+impl From<SubstituteError> for syn::Error {
+    fn from(e: SubstituteError) -> Self {
+        match e {
+            SubstituteError::FreeParameter(param) => {
+                Self::new(param.name().span().unwrap_or_else(Span::call_site), format!("undeclared variable `{}'", param.name()))
+            }
+            SubstituteError::WrongArgCount { call, expected } => {
+                Self::new(call.span().unwrap_or_else(Span::call_site), format!("wrong number of arguments. Expected {}, got {}", expected, call.args().len()))
+            }
+        }
+    }
+}
+
 impl Display for SubstituteError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
@@ -378,8 +391,8 @@ impl Display for SubstituteError {
                     "{}:{}: wrong number of arguments. Expected {}, got {}",
                     start.line,
                     start.column,
-                    call.args().len(),
-                    expected
+                    expected,
+                    call.args().len()
                 )
             }
         }
-- 
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