fix #205 Negative literals (#323)

* fix #205

Signed-off-by: Axel Nennker <axel.nennker@telekom.de>

* remove comment

Signed-off-by: Axel Nennker <axel.nennker@telekom.de>

src/bindgen/ir/constant.rs

@@ -19,6 +19,7 @@ use bindgen::ir::{
 use bindgen::library::Library;
 use bindgen::writer::{Source, SourceWriter};
 use bindgen::Bindings;
+use syn::UnOp;
 
 #[derive(Debug, Clone)]
 pub enum Literal {
@@ -209,7 +210,18 @@ impl Literal {
                     fields: field_pairs,
                 })
             }
-            _ => Err("Unsupported literal expression.".to_owned()),
+            syn::Expr::Unary(syn::ExprUnary {
+                attrs: _,
+                ref op,
+                ref expr,
+            }) => match *op {
+                UnOp::Neg(_) => {
+                    let val = Self::load(expr)?;
+                    Ok(Literal::Expr(format!("-{}", val)))
+                }
+                _ => Err(format!("Unsupported Unary expression. {:?}", *op)),
+            },
+            _ => Err(format!("Unsupported literal expression. {:?}", *expr)),
         }
     }
 }

tests/expectations/both/constant.c

@@ -11,8 +11,12 @@
 
 #define LEFTCURLY '{'
 
+#define NEG_ONE -1
+
 #define NEWLINE '\n'
 
+#define POS_ONE 1
+
 #define QUOTE '\''
 
 #define TAB '\t'

tests/expectations/constant.c

@@ -11,8 +11,12 @@
 
 #define LEFTCURLY '{'
 
+#define NEG_ONE -1
+
 #define NEWLINE '\n'
 
+#define POS_ONE 1
+
 #define QUOTE '\''
 
 #define TAB '\t'

tests/expectations/constant.cpp

@@ -10,8 +10,12 @@ static const wchar_t HEART = L'\u2764';
 
 static const wchar_t LEFTCURLY = '{';
 
+static const int8_t NEG_ONE = -1;
+
 static const wchar_t NEWLINE = '\n';
 
+static const int8_t POS_ONE = 1;
+
 static const wchar_t QUOTE = '\'';
 
 static const wchar_t TAB = '\t';

tests/expectations/tag/constant.c

@@ -11,8 +11,12 @@
 
 #define LEFTCURLY '{'
 
+#define NEG_ONE -1
+
 #define NEWLINE '\n'
 
+#define POS_ONE 1
+
 #define QUOTE '\''
 
 #define TAB '\t'

tests/rust/constant.rs

@@ -11,6 +11,9 @@ pub const ZOM: f32 = 3.14;
 pub(crate) const DONT_EXPORT_CRATE: i32 = 20;
 const DONT_EXPORT_PRIV: i32 = 30;
 
+pub const POS_ONE: i8 = 1;
+pub const NEG_ONE: i8 = -1;
+
 #[repr(C)]
 struct Foo {
     x: [i32; FOO],