Added when keyword

src/flattening/flatten.rs

@@ -1112,18 +1112,30 @@ impl<'l, 'errs> FlatteningContext<'l, 'errs> {
 
     fn flatten_if_statement(&mut self, cursor: &mut Cursor) {
         cursor.go_down(kind!("if_statement"), |cursor| {
+            cursor.field(field!("if_literal"));
+            let is_if_literal = cursor.kind() == kw!("if");
+            let position_if_literal = cursor.span();
             cursor.field(field!("condition"));
             let (condition, condition_is_generative) = self.flatten_expr(cursor);
-
             let if_id = self.instructions.alloc(Instruction::IfStatement(IfStatement {
                 condition,
                 is_generative: condition_is_generative,// TODO `if` vs `when` https://github.com/pc2/sus-compiler/issues/3
                 then_start: FlatID::PLACEHOLDER,
                 then_end_else_start: FlatID::PLACEHOLDER,
                 else_end: FlatID::PLACEHOLDER,
             }));
-            let then_start = self.instructions.get_next_alloc_id();
 
+            match(is_if_literal, condition_is_generative){
+                (true, false) => {
+                    self.errors.warn(position_if_literal, "Used 'if' in a non generative context");
+                },
+                (false, true) => {
+                    self.errors.error(position_if_literal, "Used 'when' in a generative context");
+                },
+                (_, _) => ()
+            }
+
+            let then_start = self.instructions.get_next_alloc_id();
             cursor.field(field!("then_block"));
             self.flatten_code(cursor);
 

src/flattening/initialization.rs

@@ -78,6 +78,7 @@ impl<'linker> InitializationContext<'linker> {
 
     fn gather_ports_in_if_stmt(&mut self, cursor: &mut Cursor) {
         cursor.go_down_no_check(|cursor| {
+            cursor.field(field!("if_literal"));
             cursor.field(field!("condition"));
             cursor.field(field!("then_block"));
             self.gather_all_ports_in_block(cursor);

tree-sitter-sus/grammar.js

@@ -76,7 +76,7 @@ module.exports = grammar({
             'const',
             field('const_type', $._type)
         ),
-        
+
         // Template Declaration
 
         template_declaration_arguments: $ => seq(
@@ -99,9 +99,9 @@ module.exports = grammar({
             newlineSepSeq($, choice(
                 $.block,
                 $.decl_assign_statement,
-    
-                // Decls should only allow a single declaration, and cannot contain expressions, 
-                // but we allow some tolerance in the grammar here, so we can generate better errors after. 
+
+                // Decls should only allow a single declaration, and cannot contain expressions,
+                // but we allow some tolerance in the grammar here, so we can generate better errors after.
                 $.assign_left_side,
                 $.if_statement,
                 $.for_statement,
@@ -130,7 +130,10 @@ module.exports = grammar({
         ),
 
         if_statement: $ => seq(
-            'if',
+            field('if_literal',choice(
+                'when',
+                'if'
+            )),
             field('condition', $._expression),
             //optional(field('conditional_bindings', $.interface_ports)),
             field('then_block', $.block),
@@ -158,7 +161,7 @@ module.exports = grammar({
             'domain',
             field('name', $.identifier),
         ),
-        
+
         interface_statement: $ => seq(
             'interface',//field('interface_kind', choice('action', 'query', 'trigger')),
             field('name', $.identifier),
@@ -268,7 +271,7 @@ module.exports = grammar({
             '.',
             field('name', $.identifier)
         )),
-        
+
         parenthesis_expression_list: $ => seq(
             '(',
             sepSeq($._expression, $._comma),
@@ -299,7 +302,7 @@ module.exports = grammar({
             // Template
             optional(field('template_args', $.template_args))
         ),
-        
+
         template_args: $ => seq(
             '#(',
             commaSepSeq($, $.template_arg),
@@ -345,3 +348,4 @@ module.exports = grammar({
         $.multi_line_comment
     ]
 });
+