support pub attribute (#263)

* support pub attribute for struct fields

Author: katat

examples/assignment.no

@@ -1,5 +1,5 @@
 struct Thing {
-    xx: Field,
+    pub xx: Field,
 }
 
 fn try_to_mutate(thing: Thing) {

examples/hint.no

@@ -1,6 +1,6 @@
 struct Thing {
-    xx: Field,
-    yy: Field,
+    pub xx: Field,
+    pub yy: Field,
 }
 
 hint fn mul(lhs: Field, rhs: Field) -> Field {

examples/types.no

@@ -1,6 +1,6 @@
 struct Thing {
-    xx: Field,
-    yy: Field,
+    pub xx: Field,
+    pub yy: Field,
 }
 
 fn main(pub xx: Field, pub yy: Field) {

examples/types_array.no

@@ -1,6 +1,6 @@
 struct Thing {
-    xx: Field,
-    yy: Field,
+    pub xx: Field,
+    pub yy: Field,
 }
 
 fn main(pub xx: Field, pub yy: Field) {

examples/types_array_output.no

@@ -1,6 +1,6 @@
 struct Thing {
-    xx: Field,
-    yy: Field,
+    pub xx: Field,
+    pub yy: Field,
 }
 
 fn main(pub xx: Field, pub yy: Field) -> [Thing; 2] {

src/circuit_writer/ir.rs

@@ -706,7 +706,7 @@ impl<B: Backend> IRWriter<B> {
                 // find range of field
                 let mut start = 0;
                 let mut len = 0;
-                for (field, field_typ) in &struct_info.fields {
+                for (field, field_typ, _attribute) in &struct_info.fields {
                     if field == &rhs.value {
                         len = self.size_of(field_typ);
                         break;

src/circuit_writer/writer.rs

@@ -320,7 +320,7 @@ impl<B: Backend> CircuitWriter<B> {
                     .clone();
 
                 let mut offset = 0;
-                for (_field_name, field_typ) in &struct_info.fields {
+                for (_field_name, field_typ, _attribute) in &struct_info.fields {
                     let len = self.size_of(field_typ);
                     let range = offset..(offset + len);
                     self.constrain_inputs_to_main(&input[range], field_typ, span)?;
@@ -501,7 +501,7 @@ impl<B: Backend> CircuitWriter<B> {
                 // find range of field
                 let mut start = 0;
                 let mut len = 0;
-                for (field, field_typ) in &struct_info.fields {
+                for (field, field_typ, _attribute) in &struct_info.fields {
                     if field == &rhs.value {
                         len = self.size_of(field_typ);
                         break;

src/error.rs

@@ -372,6 +372,9 @@ pub enum ErrorKind {
     #[error("division by zero")]
     DivisionByZero,
 
+    #[error("cannot access private field `{1}` of struct `{0}` from outside its methods.")]
+    PrivateFieldAccess(String, String),
+
     #[error("lhs `{0}` is less than rhs `{1}`")]
     NegativeLhsLessThanRhs(String, String),
 

src/inputs.rs

@@ -141,7 +141,7 @@ impl<B: Backend> CompiledCircuit<B> {
 
                 // parse each field
                 let mut res = vec![];
-                for (field_name, field_ty) in fields {
+                for (field_name, field_ty, _attribute) in fields {
                     let value = map.remove(field_name).ok_or_else(|| {
                         ParsingError::MissingStructFieldIdent(field_name.to_string())
                     })?;

src/mast/mod.rs

@@ -463,7 +463,7 @@ impl<B: Backend> Mast<B> {
 
                 let mut sum = 0;
 
-                for (_, t) in &struct_info.fields {
+                for (_, t, _) in &struct_info.fields {
                     sum += self.size_of(t);
                 }
 
@@ -567,8 +567,8 @@ fn monomorphize_expr<B: Backend>(
             let typ = struct_info
                 .fields
                 .iter()
-                .find(|(name, _)| name == &rhs.value)
-                .map(|(_, typ)| typ.clone());
+                .find(|(name, _, _)| name == &rhs.value)
+                .map(|(_, typ, _)| typ.clone());
 
             let mexpr = expr.to_mast(
                 ctx,