Remove hashing of the entire script by making Expr and Stmt Hash.

src/parser.rs

@@ -41,8 +41,6 @@ type FunctionsLib = HashMap<NonZeroU64, ScriptFnDef, StraightHasherBuilder>;
 struct ParseState<'e> {
     /// Reference to the scripting [`Engine`].
     engine: &'e Engine,
-    /// Hash that uniquely identifies a script.
-    script_hash: u64,
     /// Interned strings.
     strings: HashMap<String, ImmutableString>,
     /// Encapsulates a local stack with variable names to simulate an actual runtime scope.
@@ -75,7 +73,6 @@ impl<'e> ParseState<'e> {
     #[inline(always)]
     pub fn new(
         engine: &'e Engine,
-        script_hash: u64,
         #[cfg(not(feature = "unchecked"))] max_expr_depth: usize,
         #[cfg(not(feature = "unchecked"))]
         #[cfg(not(feature = "no_function"))]
@@ -83,7 +80,6 @@ impl<'e> ParseState<'e> {
     ) -> Self {
         Self {
             engine,
-            script_hash,
             #[cfg(not(feature = "unchecked"))]
             max_expr_depth,
             #[cfg(not(feature = "unchecked"))]
@@ -919,7 +915,7 @@ fn parse_switch(
 
     Ok(Stmt::Switch(
         item,
-        Box::new((final_table, def_stmt)),
+        Box::new((final_table.into(), def_stmt)),
         settings.pos,
     ))
 }
@@ -956,7 +952,7 @@ fn parse_primary(
         },
         #[cfg(not(feature = "no_float"))]
         Token::FloatConstant(x) => {
-            let x = *x;
+            let x = (*x).into();
             input.next().unwrap();
             Expr::FloatConstant(x, settings.pos)
         }
@@ -986,7 +982,6 @@ fn parse_primary(
         Token::Pipe | Token::Or if settings.allow_anonymous_fn => {
             let mut new_state = ParseState::new(
                 state.engine,
-                state.script_hash,
                 #[cfg(not(feature = "unchecked"))]
                 state.max_function_expr_depth,
                 #[cfg(not(feature = "unchecked"))]
@@ -1284,7 +1279,7 @@ fn parse_unary(
                     .map(|i| Expr::IntegerConstant(i, pos))
                     .or_else(|| {
                         #[cfg(not(feature = "no_float"))]
-                        return Some(Expr::FloatConstant(-(num as FLOAT), pos));
+                        return Some(Expr::FloatConstant((-(num as FLOAT)).into(), pos));
                         #[cfg(feature = "no_float")]
                         return None;
                     })
@@ -1292,7 +1287,7 @@ fn parse_unary(
 
                 // Negative float
                 #[cfg(not(feature = "no_float"))]
-                Expr::FloatConstant(x, pos) => Ok(Expr::FloatConstant(-x, pos)),
+                Expr::FloatConstant(x, pos) => Ok(Expr::FloatConstant((-(*x)).into(), pos)),
 
                 // Call negative function
                 expr => {
@@ -1998,14 +1993,7 @@ fn parse_custom_syntax(
         }
     }
 
-    Ok(Expr::Custom(
-        Box::new(CustomExpr {
-            keywords,
-            func: syntax.func.clone(),
-            tokens,
-        }),
-        pos,
-    ))
+    Ok(Expr::Custom(Box::new(CustomExpr { keywords, tokens }), pos))
 }
 
 /// Parse an expression.
@@ -2600,7 +2588,6 @@ fn parse_stmt(
                 (Token::Fn, pos) => {
                     let mut new_state = ParseState::new(
                         state.engine,
-                        state.script_hash,
                         #[cfg(not(feature = "unchecked"))]
                         state.max_function_expr_depth,
                         #[cfg(not(feature = "unchecked"))]
@@ -3009,10 +2996,10 @@ fn parse_anon_fn(
         params.into_iter().map(|(v, _)| v).collect()
     };
 
-    // Create unique function name by hashing the script hash plus the position
+    // Create unique function name by hashing the script body plus the parameters.
     let hasher = &mut get_hasher();
-    state.script_hash.hash(hasher);
-    settings.pos.hash(hasher);
+    params.iter().for_each(|p| p.as_str().hash(hasher));
+    body.hash(hasher);
     let hash = hasher.finish();
 
     let fn_name: ImmutableString = format!("{}{:016x}", crate::engine::FN_ANONYMOUS, hash).into();
@@ -3045,7 +3032,6 @@ fn parse_anon_fn(
 impl Engine {
     pub(crate) fn parse_global_expr(
         &self,
-        script_hash: u64,
         input: &mut TokenStream,
         scope: &Scope,
         optimization_level: OptimizationLevel,
@@ -3053,7 +3039,6 @@ impl Engine {
         let mut functions = Default::default();
         let mut state = ParseState::new(
             self,
-            script_hash,
             #[cfg(not(feature = "unchecked"))]
             self.max_expr_depth(),
             #[cfg(not(feature = "unchecked"))]
@@ -3095,14 +3080,12 @@ impl Engine {
     /// Parse the global level statements.
     fn parse_global_level(
         &self,
-        script_hash: u64,
         input: &mut TokenStream,
     ) -> Result<(Vec<Stmt>, Vec<ScriptFnDef>), ParseError> {
         let mut statements = Vec::with_capacity(16);
         let mut functions = HashMap::with_capacity_and_hasher(16, StraightHasherBuilder);
         let mut state = ParseState::new(
             self,
-            script_hash,
             #[cfg(not(feature = "unchecked"))]
             self.max_expr_depth(),
             #[cfg(not(feature = "unchecked"))]
@@ -3165,12 +3148,11 @@ impl Engine {
     #[inline(always)]
     pub(crate) fn parse(
         &self,
-        script_hash: u64,
         input: &mut TokenStream,
         scope: &Scope,
         optimization_level: OptimizationLevel,
     ) -> Result<AST, ParseError> {
-        let (statements, lib) = self.parse_global_level(script_hash, input)?;
+        let (statements, lib) = self.parse_global_level(input)?;
 
         Ok(
             // Optimize AST