implemented statement check

nac3core/src/context/inference_context.rs

@@ -22,14 +22,14 @@ pub struct InferenceContext<'a> {
     primitives: Vec<Type>,
     /// list of variable instances
     variables: Vec<Type>,
-    /// identifier to (type, readable) mapping.
-    /// an identifier might be defined earlier but has no value (for some code path), thus not
-    /// readable.
-    sym_table: HashMap<&'a str, (Type, bool)>,
+    /// identifier to type mapping.
+    sym_table: HashMap<&'a str, Type>,
     /// resolution function reference, that may resolve unbounded identifiers to some type
     resolution_fn: Box<dyn FnMut(&str) -> Result<Type, String>>,
     /// stack
     stack: ContextStack<'a>,
+    /// return type
+    result: Option<Type>,
 }
 
 // non-trivial implementations here
@@ -56,6 +56,7 @@ impl<'a> InferenceContext<'a> {
                 var_defs: Vec::new(),
                 sym_def: Vec::new(),
             },
+            result: None,
         }
     }
 
@@ -63,7 +64,7 @@ impl<'a> InferenceContext<'a> {
     /// variable assignment would be limited within the scope (not readable outside), and type
     /// variable type guard would be limited within the scope.
     /// returns the list of variables assigned within the scope, and the result of the function
-    pub fn with_scope<F, R>(&mut self, f: F) -> (Vec<&'a str>, R)
+    pub fn with_scope<F, R>(&mut self, f: F) -> (Vec<(&'a str, Type)>, R)
     where
         F: FnOnce(&mut Self) -> R,
     {
@@ -84,8 +85,8 @@ impl<'a> InferenceContext<'a> {
             let (_, level) = self.stack.sym_def.last().unwrap();
             if *level > self.stack.level {
                 let (name, _) = self.stack.sym_def.pop().unwrap();
-                self.sym_table.remove(name).unwrap();
-                poped_names.push(name);
+                let ty = self.sym_table.remove(name).unwrap();
+                poped_names.push((name, ty));
             } else {
                 break;
             }
@@ -96,19 +97,15 @@ impl<'a> InferenceContext<'a> {
     /// assign a type to an identifier.
     /// may return error if the identifier was defined but with different type
     pub fn assign(&mut self, name: &'a str, ty: Type) -> Result<Type, String> {
-        if let Some((t, x)) = self.sym_table.get_mut(name) {
+        if let Some(t) = self.sym_table.get_mut(name) {
             if t == &ty {
-                if !*x {
-                    self.stack.sym_def.push((name, self.stack.level));
-                }
-                *x = true;
                 Ok(ty)
             } else {
                 Err("different types".into())
             }
         } else {
             self.stack.sym_def.push((name, self.stack.level));
-            self.sym_table.insert(name, (ty.clone(), true));
+            self.sym_table.insert(name, ty.clone());
             Ok(ty)
         }
     }
@@ -122,12 +119,8 @@ impl<'a> InferenceContext<'a> {
     /// may return error if the identifier is not defined, and cannot be resolved with the
     /// resolution function.
     pub fn resolve(&mut self, name: &str) -> Result<Type, String> {
-        if let Some((t, x)) = self.sym_table.get(name) {
-            if *x {
-                Ok(t.clone())
-            } else {
-                Err("may not have value".into())
-            }
+        if let Some(t) = self.sym_table.get(name) {
+            Ok(t.clone())
         } else {
             self.resolution_fn.as_mut()(name)
         }
@@ -139,6 +132,10 @@ impl<'a> InferenceContext<'a> {
         std::mem::swap(self.top_level.var_defs.get_mut(id.0).unwrap(), &mut def);
         self.stack.var_defs.push((id.0, def, self.stack.level));
     }
+
+    pub fn set_result(&mut self, result: Option<Type>) {
+        self.result = result;
+    }
 }
 
 // trivial getters:
@@ -168,6 +165,9 @@ impl<'a> InferenceContext<'a> {
     pub fn get_type(&self, name: &str) -> Option<Type> {
         self.top_level.get_type(name)
     }
+    pub fn get_result(&self) -> Option<Type> {
+        self.result.clone()
+    }
 }
 
 impl TypeEnum {

nac3core/src/expression_inference.rs

@@ -303,7 +303,7 @@ fn infer_if_expr<'b: 'a, 'a>(
     }
 }
 
-fn infer_simple_binding<'a: 'b, 'b>(
+pub fn infer_simple_binding<'a: 'b, 'b>(
     ctx: &mut InferenceContext<'b>,
     name: &'a Expression,
     ty: Type,

nac3core/src/lib.rs

@@ -7,7 +7,7 @@ extern crate rustpython_parser;
 
 pub mod expression_inference;
 pub mod inference_core;
-pub mod statement_inference;
+pub mod statement_check;
 mod magic_methods;
 pub mod primitives;
 pub mod typedef;

nac3core/src/statement_check.rs

@@ -0,0 +1,241 @@
+use crate::context::InferenceContext;
+use crate::expression_inference::{infer_expr, infer_simple_binding};
+use crate::inference_core::resolve_call;
+use crate::magic_methods::binop_assign_name;
+use crate::primitives::*;
+use crate::typedef::{Type, TypeEnum::*};
+use rustpython_parser::ast::*;
+
+pub fn check_stmts<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    stmts: &'b [Statement],
+) -> Result<bool, String> {
+    for stmt in stmts.iter() {
+        match &stmt.node {
+            StatementType::Assign { targets, value } => {
+                check_assign(ctx, targets.as_slice(), &value)?;
+            }
+            StatementType::AugAssign { target, op, value } => {
+                check_aug_assign(ctx, &target, op, &value)?;
+            }
+            StatementType::If { test, body, orelse } => {
+                check_if(ctx, test, body.as_slice(), orelse)?;
+            }
+            StatementType::While { test, body, orelse } => {
+                check_while_stmt(ctx, test, body.as_slice(), orelse)?;
+            }
+            StatementType::For {
+                is_async,
+                target,
+                iter,
+                body,
+                orelse,
+            } => {
+                if *is_async {
+                    return Err("async for is not supported".to_string());
+                }
+                check_for_stmt(ctx, target, iter, body.as_slice(), orelse)?;
+            }
+            StatementType::Return { value } => {
+                let result = ctx.get_result();
+                let t = if let Some(value) = value {
+                    infer_expr(ctx, value)?
+                } else {
+                    None
+                };
+                return if t == result {
+                    Ok(true)
+                } else {
+                    Err("return type mismatch".to_string())
+                };
+            }
+            StatementType::Continue | StatementType::Break => {
+                continue;
+            }
+            _ => return Err("not supported".to_string()),
+        }
+    }
+    Ok(false)
+}
+
+fn get_target_type<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    target: &'b Expression,
+) -> Result<Type, String> {
+    match &target.node {
+        ExpressionType::Subscript { a, b } => {
+            let int32 = ctx.get_primitive(INT32_TYPE);
+            if infer_expr(ctx, &a)? == Some(int32) {
+                let b = get_target_type(ctx, &b)?;
+                if let ParametricType(LIST_TYPE, t) = b.as_ref() {
+                    Ok(t[0].clone())
+                } else {
+                    Err("subscript is only supported for list".to_string())
+                }
+            } else {
+                Err("subscript must be int32".to_string())
+            }
+        }
+        ExpressionType::Attribute { value, name } => {
+            let t = get_target_type(ctx, &value)?;
+            let base = t.get_base(ctx).ok_or_else(|| "no attributes".to_string())?;
+            Ok(base
+                .fields
+                .get(name.as_str())
+                .ok_or_else(|| "no such attribute")?
+                .clone())
+        }
+        ExpressionType::Identifier { name } => Ok(ctx.resolve(name.as_str())?),
+        _ => Err("not supported".to_string()),
+    }
+}
+
+fn check_stmt_binding<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    target: &'b Expression,
+    ty: Type,
+) -> Result<(), String> {
+    match &target.node {
+        ExpressionType::Identifier { name } => {
+            if name.as_str() == "_" {
+                Ok(())
+            } else {
+                match ctx.resolve(name.as_str()) {
+                    Ok(t) if t == ty => Ok(()),
+                    Err(_) => {
+                        ctx.assign(name.as_str(), ty).unwrap();
+                        Ok(())
+                    }
+                    _ => Err("conflicting type".into()),
+                }
+            }
+        }
+        ExpressionType::Tuple { elements } => {
+            if let ParametricType(TUPLE_TYPE, ls) = ty.as_ref() {
+                if ls.len() != elements.len() {
+                    return Err("incorrect pattern length".into());
+                }
+                for (x, y) in elements.iter().zip(ls.iter()) {
+                    check_stmt_binding(ctx, x, y.clone())?;
+                }
+                Ok(())
+            } else {
+                Err("pattern matching supports tuple only".into())
+            }
+        }
+        _ => {
+            let t = get_target_type(ctx, target)?;
+            if ty == t {
+                Ok(())
+            } else {
+                Err("type mismatch".into())
+            }
+        }
+    }
+}
+
+fn check_assign<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    targets: &'b [Expression],
+    value: &'b Expression,
+) -> Result<(), String> {
+    let ty = infer_expr(ctx, value)?.ok_or_else(|| "no value".to_string())?;
+    for t in targets.iter() {
+        check_stmt_binding(ctx, t, ty.clone())?;
+    }
+    Ok(())
+}
+
+fn check_aug_assign<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    target: &'b Expression,
+    op: &'b Operator,
+    value: &'b Expression,
+) -> Result<(), String> {
+    let left = infer_expr(ctx, target)?.ok_or_else(|| "no value".to_string())?;
+    let right = infer_expr(ctx, value)?.ok_or_else(|| "no value".to_string())?;
+    let fun = binop_assign_name(op);
+    resolve_call(ctx, Some(left), fun, &[right])?;
+    Ok(())
+}
+
+fn check_if<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    test: &'b Expression,
+    body: &'b [Statement],
+    orelse: &'b Option<Suite>,
+) -> Result<bool, String> {
+    let boolean = ctx.get_primitive(BOOL_TYPE);
+    let t = infer_expr(ctx, test)?;
+    if t == Some(boolean) {
+        let (names, result) = ctx.with_scope(|ctx| check_stmts(ctx, body));
+        let returned = result?;
+        if let Some(orelse) = orelse {
+            let (names2, result) = ctx.with_scope(|ctx| check_stmts(ctx, orelse.as_slice()));
+            let returned = returned && result?;
+            for (name, ty) in names.iter() {
+                for (name2, ty2) in names2.iter() {
+                    if *name == *name2 && ty == ty2 {
+                        ctx.assign(name, ty.clone()).unwrap();
+                    }
+                }
+            }
+            Ok(returned)
+        } else {
+            Ok(false)
+        }
+    } else {
+        Err("condition should be bool".to_string())
+    }
+}
+
+fn check_while_stmt<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    test: &'b Expression,
+    body: &'b [Statement],
+    orelse: &'b Option<Suite>,
+) -> Result<bool, String> {
+    let boolean = ctx.get_primitive(BOOL_TYPE);
+    let t = infer_expr(ctx, test)?;
+    if t == Some(boolean) {
+        // to check what variables are defined, we would have to do a graph analysis...
+        // not implemented now
+        let (_, result) = ctx.with_scope(|ctx| check_stmts(ctx, body));
+        result?;
+        if let Some(orelse) = orelse {
+            let (_, result) = ctx.with_scope(|ctx| check_stmts(ctx, orelse.as_slice()));
+            result?;
+        }
+        // to check whether the loop returned on every possible path, we need to analyse the graph,
+        // not implemented now
+        Ok(false)
+    } else {
+        Err("condition should be bool".to_string())
+    }
+}
+
+fn check_for_stmt<'b: 'a, 'a>(
+    ctx: &mut InferenceContext<'a>,
+    target: &'b Expression,
+    iter: &'b Expression,
+    body: &'b [Statement],
+    orelse: &'b Option<Suite>,
+) -> Result<bool, String> {
+    let ty = infer_expr(ctx, iter)?.ok_or_else(|| "no value".to_string())?;
+    if let ParametricType(LIST_TYPE, ls) = ty.as_ref() {
+        let (_, result) = ctx.with_scope(|ctx| {
+            infer_simple_binding(ctx, target, ls[0].clone())?;
+            check_stmts(ctx, body)
+        });
+        result?;
+        if let Some(orelse) = orelse {
+            let (_, result) = ctx.with_scope(|ctx| check_stmts(ctx, orelse.as_slice()));
+            result?;
+        }
+        // to check whether the loop returned on every possible path, we need to analyse the graph,
+        // not implemented now
+        Ok(false)
+    } else {
+        Err("only list can be iterated over".to_string())
+    }
+}

nac3core/src/statement_inference.rs

@@ -1,95 +0,0 @@
-use crate::context::InferenceContext;
-use crate::expression_inference::infer_expr;
-use crate::inference_core::resolve_call;
-use crate::magic_methods::*;
-use crate::primitives::*;
-use crate::typedef::{Type, TypeEnum::*};
-use rustpython_parser::ast::*;
-
-fn get_target_type<'b: 'a, 'a>(
-    ctx: &mut InferenceContext<'a>,
-    target: &'b Expression,
-) -> Result<Type, String> {
-    match &target.node {
-        ExpressionType::Subscript { a, b } => {
-            let int32 = ctx.get_primitive(INT32_TYPE);
-            if infer_expr(ctx, &a)? == Some(int32) {
-                let b = get_target_type(ctx, &b)?;
-                if let ParametricType(LIST_TYPE, t) = b.as_ref() {
-                    Ok(t[0].clone())
-                } else {
-                    Err("subscript is only supported for list".to_string())
-                }
-            } else {
-                Err("subscript must be int32".to_string())
-            }
-        }
-        ExpressionType::Attribute { value, name } => {
-            let t = get_target_type(ctx, &value)?;
-            let base = t.get_base(ctx).ok_or_else(|| "no attributes".to_string())?;
-            Ok(base
-                .fields
-                .get(name.as_str())
-                .ok_or_else(|| "no such attribute")?
-                .clone())
-        }
-        ExpressionType::Identifier { name } => Ok(ctx.resolve(name.as_str())?),
-        _ => Err("not supported".to_string()),
-    }
-}
-
-fn check_stmt_binding<'b: 'a, 'a>(
-    ctx: &mut InferenceContext<'a>,
-    target: &'b Expression,
-    ty: Type,
-) -> Result<(), String> {
-    match &target.node {
-        ExpressionType::Identifier { name } => {
-            if name.as_str() == "_" {
-                Ok(())
-            } else {
-                match ctx.resolve(name.as_str()) {
-                    Ok(t) if t == ty => Ok(()),
-                    Err(_) => {
-                        ctx.assign(name.as_str(), ty).unwrap();
-                        Ok(())
-                    }
-                    _ => Err("conflicting type".into()),
-                }
-            }
-        }
-        ExpressionType::Tuple { elements } => {
-            if let ParametricType(TUPLE_TYPE, ls) = ty.as_ref() {
-                if ls.len() != elements.len() {
-                    return Err("incorrect pattern length".into());
-                }
-                for (x, y) in elements.iter().zip(ls.iter()) {
-                    check_stmt_binding(ctx, x, y.clone())?;
-                }
-                Ok(())
-            } else {
-                Err("pattern matching supports tuple only".into())
-            }
-        }
-        _ => {
-            let t = get_target_type(ctx, target)?;
-            if ty == t {
-                Ok(())
-            } else {
-                Err("type mismatch".into())
-            }
-        }
-    }
-}
-
-fn check_assign<'b: 'a, 'a>(
-    ctx: &mut InferenceContext<'a>,
-    targets: &'b [Expression],
-    value: &'b Expression,
-) -> Result<(), String> {
-    let ty = infer_expr(ctx, value)?.ok_or_else(|| "no value".to_string())?;
-    for t in targets.iter() {
-        check_stmt_binding(ctx, t, ty.clone())?;
-    }
-    Ok(())
-}