add variable table to function body

dynamic-check/src/dynamic_check.rs

@@ -14,15 +14,15 @@
 // You should have received a copy of the GNU General Public License
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
+use leo_static_check::{FunctionInputType, FunctionType, SymbolTable, Type};
 use leo_typed::{Expression, Function, Identifier, Program, Span, Statement};
 
-use leo_static_check::{FunctionType, SymbolTable, Type};
 use serde::{Deserialize, Serialize};
-use std::collections::HashSet;
+use std::collections::HashMap;
 
 /// Performs a dynamic type inference check over a program.
 pub struct DynamicCheck {
-    symbol_table: SymbolTable,
+    table: SymbolTable,
     functions: Vec<FunctionBody>,
 }
 
@@ -32,7 +32,7 @@ impl DynamicCheck {
     ///
     pub fn new(program: &Program, symbol_table: SymbolTable) -> Self {
         let mut dynamic_check = Self {
-            symbol_table,
+            table: symbol_table,
             functions: vec![],
         };
 
@@ -67,7 +67,7 @@ impl DynamicCheck {
     /// Collects a vector of `TypeAssertion` predicates from a function.
     ///
     fn parse_function(&mut self, function: &Function) {
-        let function_body = FunctionBody::new(function.clone(), self.symbol_table.clone());
+        let function_body = FunctionBody::new(function.clone(), self.table.clone());
 
         self.functions.push(function_body);
     }
@@ -92,9 +92,9 @@ impl DynamicCheck {
 #[derive(Clone)]
 pub struct FunctionBody {
     function_type: FunctionType,
-    symbol_table: SymbolTable,
+    user_defined_types: SymbolTable,
     type_assertions: Vec<TypeAssertion>,
-    type_variables: HashSet<TypeVariable>,
+    variable_table: VariableTable,
 }
 
 impl FunctionBody {
@@ -107,18 +107,21 @@ impl FunctionBody {
         // Get function type from symbol table.
         let function_type = symbol_table.get_function(name).unwrap().clone();
 
+        // Build symbol table for variables.
+        let mut variable_table = VariableTable::new();
+
+        // Initialize function inputs as variables.
+        variable_table.parse_function_inputs(&function_type.inputs);
+
         // Create new function body struct.
+        // Update variables when encountering let/const variable definitions.
         let mut function_body = Self {
             function_type,
-            symbol_table,
+            user_defined_types: symbol_table,
             type_assertions: vec![],
-            type_variables: HashSet::new(),
+            variable_table,
         };
 
-        // Build symbol table for variables.
-        // Initialize function inputs as variables.
-        // Update inputs when encountering let/const variable definitions.
-
         // Create type assertions for function statements
         function_body.parse_statements(&function.statements);
 
@@ -157,7 +160,7 @@ impl FunctionBody {
         let left = TypeElement::Type(output_type.clone());
 
         // Create the right hand side from the statement return expression.
-        let right = TypeElement::new(expression, self.symbol_table.clone());
+        let right = TypeElement::new(expression, self.user_defined_types.clone());
 
         // Create a new type assertion for the statement return.
         let type_assertion = TypeAssertion::new(left, right);
@@ -198,6 +201,44 @@ impl FunctionBody {
     }
 }
 
+/// A structure for tracking the types of user defined variables in a program.
+#[derive(Clone)]
+pub struct VariableTable(pub HashMap<String, Type>);
+
+impl VariableTable {
+    ///
+    /// Return a new variable table
+    ///
+    pub fn new() -> Self {
+        Self(HashMap::new())
+    }
+
+    ///
+    /// Insert a name -> type pair into the variable table.
+    ///
+    /// If the variable table did not have this key present, [`None`] is returned.
+    ///
+    /// If the variable table did have this key present, the type is updated, and the old
+    /// type is returned.
+    ///
+    pub fn insert(&mut self, name: String, type_: Type) -> Option<Type> {
+        self.0.insert(name, type_)
+    }
+
+    ///
+    /// Inserts a vector of function input types into the variable table.
+    ///
+    pub fn parse_function_inputs(&mut self, function_inputs: &Vec<FunctionInputType>) {
+        for input in function_inputs {
+            let input_name = input.identifier().name.clone();
+            let input_type = input.type_().clone();
+
+            // TODO (collinc97) throw an error for duplicate function input names.
+            self.insert(input_name, input_type);
+        }
+    }
+}
+
 /// A predicate that evaluates equality between two `TypeElement`s.
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
 pub struct TypeAssertion {

static-check/src/static_check.rs

@@ -15,7 +15,7 @@
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{SymbolTable, SymbolTableError};
-use leo_typed::Program as UnresolvedProgram;
+use leo_typed::Program;
 
 /// Performs a static type check over a program.
 pub struct StaticCheck {
@@ -26,7 +26,7 @@ impl StaticCheck {
     ///
     /// Return a new `StaticCheck` from a given program.
     ///
-    pub fn new(program: &UnresolvedProgram) -> Result<SymbolTable, SymbolTableError> {
+    pub fn new(program: &Program) -> Result<SymbolTable, SymbolTableError> {
         let mut check = Self {
             table: SymbolTable::new(None),
         };
@@ -46,7 +46,7 @@ impl StaticCheck {
     /// If a circuit or function name has no duplicates, then it is inserted into the symbol table.
     /// Variables defined later in the unresolved program cannot have the same name.
     ///
-    pub fn pass_one(&mut self, program: &UnresolvedProgram) -> Result<(), SymbolTableError> {
+    pub fn pass_one(&mut self, program: &Program) -> Result<(), SymbolTableError> {
         // Check unresolved program circuit names.
         self.table.check_duplicate_circuits(&program.circuits)?;
 
@@ -63,7 +63,7 @@ impl StaticCheck {
     /// symbol table. Variables defined later in the unresolved program can lookup the definition and
     /// refer to its expected types.
     ///
-    pub fn pass_two(&mut self, program: &UnresolvedProgram) -> Result<(), SymbolTableError> {
+    pub fn pass_two(&mut self, program: &Program) -> Result<(), SymbolTableError> {
         // Check unresolved program circuit definitions.
         self.table.check_unknown_types_circuits(&program.circuits)?;