[glsl-new] match wgsl expression order (#147)

src/front/glsl_new/ast.rs

@@ -35,6 +35,7 @@ impl Program {
                 expressions: Arena::<Expression>::new(),
                 local_variables: Arena::<LocalVariable>::new(),
                 scopes: vec![FastHashMap::default()],
+                lookup_global_var_exps: FastHashMap::default(),
             },
         }
     }
@@ -50,11 +51,12 @@ pub struct Context {
     pub expressions: Arena<Expression>,
     pub local_variables: Arena<LocalVariable>,
     //TODO: Find less allocation heavy representation
-    pub scopes: Vec<FastHashMap<String, Handle<LocalVariable>>>,
+    pub scopes: Vec<FastHashMap<String, Handle<Expression>>>,
+    pub lookup_global_var_exps: FastHashMap<String, Handle<Expression>>,
 }
 
 impl Context {
-    pub fn lookup_local_var(&self, name: &str) -> Option<Handle<LocalVariable>> {
+    pub fn lookup_local_var(&self, name: &str) -> Option<Handle<Expression>> {
         for scope in self.scopes.iter().rev() {
             if let Some(var) = scope.get(name) {
                 return Some(*var);
@@ -64,7 +66,7 @@ impl Context {
     }
 
     #[cfg(feature = "glsl-validate")]
-    pub fn lookup_local_var_current_scope(&self, name: &str) -> Option<Handle<LocalVariable>> {
+    pub fn lookup_local_var_current_scope(&self, name: &str) -> Option<Handle<Expression>> {
         if let Some(current) = self.scopes.last() {
             current.get(name).cloned()
         } else {
@@ -78,7 +80,7 @@ impl Context {
     }
 
     /// Add variable to current scope
-    pub fn add_local_var(&mut self, name: String, handle: Handle<LocalVariable>) {
+    pub fn add_local_var(&mut self, name: String, handle: Handle<Expression>) {
         if let Some(current) = self.scopes.last_mut() {
             (*current).insert(name, handle);
         }

src/front/glsl_new/parser.rs

@@ -156,23 +156,27 @@ pomelo! {
                     interpolation: None,
                 },
             );
-            extra.lookup_global_variables.insert(v.1, h);
+            extra.lookup_global_variables.insert(v.1.clone(), h);
+            let expression = extra.context.expressions.append(
+                Expression::GlobalVariable(h)
+            );
+            extra.context.lookup_global_var_exps.insert(v.1, expression);
             ExpressionRule{
-                expression: extra.context.expressions.append(Expression::GlobalVariable(h)),
+                expression,
                 statements: vec![],
             }
         } else {
             // try global and local vars
-            let expr =
+            let expression =
                 if let Some(local_var) = extra.context.lookup_local_var(&v.1) {
-                    Expression::LocalVariable(local_var)
-                } else if let Some(global_var) = extra.lookup_global_variables.get(&v.1) {
-                    Expression::GlobalVariable(*global_var)
+                    local_var
+                } else if let Some(global_var) = extra.context.lookup_global_var_exps.get(&v.1) {
+                    *global_var
                 } else {
                     return Err(ErrorKind::UnknownVariable(v.0, v.1))
                 };
             ExpressionRule{
-                expression: extra.context.expressions.append(expr),
+                expression,
                 statements: vec![],
             }
         }
@@ -565,7 +569,7 @@ pomelo! {
             if extra.context.lookup_local_var_current_scope(&id).is_some() {
                 return Err(ErrorKind::VariableAlreadyDeclared(id))
             }
-            let h = extra.context.local_variables.append(
+            let localVar = extra.context.local_variables.append(
                 LocalVariable {
                     name: Some(id.clone()),
                     ty: d.ty,
@@ -575,7 +579,8 @@ pomelo! {
                     }),
                 }
             );
-            extra.context.add_local_var(id, h);
+            let exp = extra.context.expressions.append(Expression::LocalVariable(localVar));
+            extra.context.add_local_var(id, exp);
         }
         match statements.len() {
             0 => Statement::Empty,
@@ -626,7 +631,18 @@ pomelo! {
 
 
     // function
-    function_prototype ::= function_declarator(f) RightParen {f}
+    function_prototype ::= function_declarator(f) RightParen {
+        // prelude, add global var expressions
+        for (var_handle, var) in extra.global_variables.iter() {
+            if let Some(name) = var.name.as_ref() {
+                let exp = extra.context.expressions.append(
+                    Expression::GlobalVariable(var_handle)
+                );
+                extra.context.lookup_global_var_exps.insert(name.clone(), exp);
+            }
+        }
+        f
+    }
     function_declarator ::= function_header;
     function_header ::= fully_specified_type(t) Identifier(n) LeftParen {
         Function {
@@ -763,6 +779,7 @@ pomelo! {
         std::mem::swap(&mut f.expressions, &mut extra.context.expressions);
         std::mem::swap(&mut f.local_variables, &mut extra.context.local_variables);
         extra.context.clear_scopes();
+        extra.context.lookup_global_var_exps.clear();
         f.body = cs;
         f.global_usage = crate::GlobalUse::scan(&f.expressions, &f.body, &extra.global_variables);
         f