From 7b1ea58bc0b0fd6e72cc28d9c8fbe934656d0ed1 Mon Sep 17 00:00:00 2001
From: pca006132 <jl@m-labs.hk>
Date: Tue, 29 Dec 2020 12:28:18 +0800
Subject: [PATCH] implemented some more expressions

---
 nac3core/src/expression.rs | 63 +++++++++++++++++++++++++++++++++++---
 nac3core/src/typedef.rs    | 16 ++++++++--
 2 files changed, 71 insertions(+), 8 deletions(-)

diff --git a/nac3core/src/expression.rs b/nac3core/src/expression.rs
index fd434aa601..c91e8c10a4 100644
--- a/nac3core/src/expression.rs
+++ b/nac3core/src/expression.rs
@@ -10,7 +10,7 @@ type SymTable<'a> = HashMap<&'a str, Rc<Type>>;
 type ParserResult = Result<Rc<Type>, String>;
 
 pub fn parse_expr(ctx: &GlobalContext, sym_table: &SymTable, expr: &Expression) -> ParserResult {
-    Err("not supported".to_string())
+    Err("not supported".into())
 }
 
 fn parse_constant(
@@ -28,18 +28,18 @@ fn parse_constant(
             // } else if i64::try_from(&value).is_ok() {
             //     Ok(PrimitiveType(INT64_TYPE).into())
             // } else {
-            //     Err("integer out of range".to_string())
+            //     Err("integer out of range".into())
             // }
         }
         Number::Float { .. } => Ok(PrimitiveType(FLOAT_TYPE).into()),
-        _ => Err("not supported".to_string()),
+        _ => Err("not supported".into()),
     }
 }
 
 fn parse_identifier(_: &GlobalContext, sym_table: &SymTable, name: &str) -> ParserResult {
     match sym_table.get(name) {
         Some(v) => Ok(v.clone()),
-        None => Err("unbounded variable".to_string()),
+        None => Err("unbounded variable".into()),
     }
 }
 
@@ -53,7 +53,7 @@ fn parse_list(ctx: &GlobalContext, sym_table: &SymTable, elements: &[Expression]
     let head = types.next().unwrap()?;
     for v in types {
         if v? != head {
-            return Err("inhomogeneous list is not allowed".to_string());
+            return Err("inhomogeneous list is not allowed".into());
         }
     }
     Ok(ParametricType(LIST_TYPE, vec![head]).into())
@@ -67,4 +67,57 @@ fn parse_tuple(ctx: &GlobalContext, sym_table: &SymTable, elements: &[Expression
     Ok(ParametricType(TUPLE_TYPE, types?).into())
 }
 
+fn parse_attribute(
+    ctx: &GlobalContext,
+    sym_table: &SymTable,
+    value: &Expression,
+    name: String,
+) -> ParserResult {
+    let value = parse_expr(ctx, sym_table, value)?;
+    if let TypeVariable(id) = value.as_ref() {
+        let v = ctx.get_variable(*id);
+        if v.bound.len() == 0 {
+            return Err("no fields on unbounded type variable".into());
+        }
+        let ty = v.bound[0]
+            .get_base(ctx)
+            .and_then(|v| v.fields.get(name.as_str()));
+        if ty.is_none() {
+            return Err("unknown field".into());
+        }
+        for x in v.bound[1..].iter() {
+            let ty1 = x.get_base(ctx).and_then(|v| v.fields.get(name.as_str()));
+            if ty1 != ty {
+                return Err("unknown field (type mismatch between variants)".into());
+            }
+        }
+        return Ok(ty.unwrap().clone());
+    }
+
+    match value.get_base(ctx) {
+        Some(b) => match b.fields.get(name.as_str()) {
+            Some(t) => Ok(t.clone()),
+            None => Err("no such field".into()),
+        },
+        None => Err("this object has no fields".into()),
+    }
+}
+
+fn parse_bool_ops(
+    ctx: &GlobalContext,
+    sym_table: &SymTable,
+    values: &[Expression],
+) -> ParserResult {
+    assert_eq!(values.len(), 2);
+    let left = parse_expr(ctx, sym_table, &values[0])?;
+    let right = parse_expr(ctx, sym_table, &values[1])?;
+
+    let b = PrimitiveType(BOOL_TYPE);
+    if left.as_ref() == &b && right.as_ref() == &b {
+        Ok(b.into())
+    } else {
+        Err("bool operands must be bool".into())
+    }
+}
+
 
diff --git a/nac3core/src/typedef.rs b/nac3core/src/typedef.rs
index d2517deb99..e4886b307b 100644
--- a/nac3core/src/typedef.rs
+++ b/nac3core/src/typedef.rs
@@ -35,7 +35,7 @@ pub struct FnDef {
 #[derive(Clone)]
 pub struct TypeDef<'a> {
     pub name: &'a str,
-    pub fields: HashMap<&'a str, Type>,
+    pub fields: HashMap<&'a str, Rc<Type>>,
     pub methods: HashMap<&'a str, FnDef>,
 }
 
@@ -194,7 +194,8 @@ impl Type {
                     .collect(),
             ),
             _ => self.clone(),
-        }.into()
+        }
+        .into()
     }
 
     pub fn get_subst(&self, ctx: &GlobalContext) -> HashMap<VariableId, Rc<Type>> {
@@ -210,5 +211,14 @@ impl Type {
             _ => HashMap::new(),
         }
     }
-}
 
+    pub fn get_base<'b: 'a, 'a>(&'a self, ctx: &'b GlobalContext) -> Option<&'b TypeDef> {
+        match self {
+            Type::PrimitiveType(id) => Some(ctx.get_primitive(*id)),
+            Type::ClassType(id)
+                | Type::VirtualClassType(id) => Some(&ctx.get_class(*id).base),
+            Type::ParametricType(id, _) => Some(&ctx.get_parametric(*id).base),
+            _ => None,
+        }
+    }
+}