[Tolk] Readonly fields in structs

Author: tolk-vm

tolk-tester/tests/assignment-tests.tolk

@@ -257,6 +257,32 @@ fun test119(a: int, b: int) {
     return (l, c, d);
 }
 
+struct Point {
+    x: int
+    y: int
+}
+
+struct ROLine {
+    readonly from: Point
+    readonly to: Point
+}
+
+fun eq<T>(v: T) { return v }
+
+@method_id(120)
+fun test120() {
+    val p: Point = { x: 10, y: 20 };
+    eq(p).x = 30;
+    return p;
+}
+
+@method_id(121)
+fun test121(l: ROLine) {
+    eq(l.from).x = eq(l.to).y;
+    eq(l.from).y += 10;
+    return l
+}
+
 
 
 fun main(value: int, ) {
@@ -288,6 +314,8 @@ fun main(value: int, ) {
 @testcase | 117 |        | [ 20 ]
 @testcase | 118 | 3      | 10 3 0 1
 @testcase | 119 | 1 2    | 2 2 4
+@testcase | 120 |        | 10 20
+@testcase | 121 | null   | (null)
 
 
 @fif_codegen

tolk-tester/tests/invalid-semantics/err-4130.tolk

@@ -0,0 +1,22 @@
+struct Point {
+    x: int
+    y: int
+}
+
+struct ROLine {
+    readonly p1: Point
+    readonly p2: Point
+}
+
+fun eq<T>(v: T) { return v }
+
+fun f(l: ROLine) {
+    l.p1; l.p2; l.p1.x; eq(l.p2.y); eq(eq(l).p2).y;
+
+    l.p2!.x += 1;
+}
+
+/**
+@compilation_should_fail
+@stderr modifying readonly field `ROLine.p2` 
+ */

tolk-tester/tests/invalid-semantics/err-4131.tolk

@@ -0,0 +1,12 @@
+struct ImmSlice {
+    readonly s: slice
+}
+
+fun ImmSlice.read(mutate self) {
+    self.s.loadRef()
+}
+
+/**
+@compilation_should_fail
+@stderr modifying readonly field `ImmSlice.s`
+ */

tolk-tester/tests/invalid-semantics/err-4132.tolk

@@ -0,0 +1,15 @@
+struct ROPoint {
+    readonly x: int
+    readonly y: int
+}
+
+fun increment(mutate x: int) {}
+
+fun main(p1: ROPoint, p2: ROPoint) {
+    increment(mutate (p1 = p2).x);
+}
+
+/**
+@compilation_should_fail
+@stderr modifying readonly field `ROPoint.x`
+ */

tolk-tester/tests/invalid-semantics/err-4572.tolk

@@ -1,6 +1,8 @@
+fun eq<T>(v: T) { return v }
+
 fun checkCantMutateFieldOfImmutableTuple() {
     val ks = null as [int, [int, [int]]]?;
-    ks!.1.1.0 = 10;
+    eq(ks!.1.1 = [10]).0 = 10;
 }
 
 /**

tolk-tester/tests/invalid-semantics/err-4822.tolk

@@ -8,8 +8,8 @@ struct Coord2 {
     p2: Point;
 }
 
-fun increment(mutate x: int) {
-    x += 1;
+fun int.increment(mutate self) {
+    self += 1;
 }
 
 fun checkCantMutateFieldOfImmutableTuple(p1: Point?, p2: Point) {
@@ -19,5 +19,5 @@ fun checkCantMutateFieldOfImmutableTuple(p1: Point?, p2: Point) {
 
 /**
 @compilation_should_fail
-@modifying immutable variable `c2`
+@stderr modifying immutable variable `c2`
  */

tolk/ast-from-tokens.cpp

@@ -1542,6 +1542,13 @@ static AnyV parse_function_declaration(Lexer& lex, const std::vector<V<ast_annot
 
 static AnyV parse_struct_field(Lexer& lex) {
   SrcLocation loc = lex.cur_location();
+
+  bool is_readonly = false;
+  if (lex.tok() == tok_readonly) {
+    lex.next();
+    is_readonly = true;
+  }
+  
   lex.check(tok_identifier, "field name");
   auto v_ident = createV<ast_identifier>(lex.cur_location(), lex.cur_str());
   lex.next();
@@ -1554,7 +1561,7 @@ static AnyV parse_struct_field(Lexer& lex) {
     default_value = parse_expr(lex);
   }
 
-  return createV<ast_struct_field>(loc, v_ident, default_value, declared_type);
+  return createV<ast_struct_field>(loc, v_ident, is_readonly, default_value, declared_type);
 }
 
 static V<ast_struct_body> parse_struct_body(Lexer& lex) {

tolk/ast-replicator.h

@@ -235,7 +235,7 @@ class ASTReplicator final {
     return createV<ast_parameter_list>(v->loc, clone(v->get_params()));
   }
   static V<ast_struct_field> clone(V<ast_struct_field> v) {
-    return createV<ast_struct_field>(v->loc, clone(v->get_identifier()), v->default_value ? clone(v->default_value) : nullptr, clone(v->type_node));
+    return createV<ast_struct_field>(v->loc, clone(v->get_identifier()), v->is_readonly, v->default_value ? clone(v->default_value) : nullptr, clone(v->type_node));
   }
   static V<ast_struct_body> clone(V<ast_struct_body> v) {
     return createV<ast_struct_body>(v->loc, clone(v->get_all_fields()));

tolk/ast.h

@@ -1353,14 +1353,15 @@ template<>
 // ast_struct_field is one field at struct declaration
 // example: `struct Point { x: int, y: int }` is struct declaration, its body contains 2 fields
 struct Vertex<ast_struct_field> final : ASTOtherVararg {
+  bool is_readonly;               // declared as `readonly field: int`
   AnyTypeV type_node;             // always exists, typing struct fields is mandatory
   AnyExprV default_value;         // nullptr if no default
 
   auto get_identifier() const { return children.at(0)->as<ast_identifier>(); }
 
-  Vertex(SrcLocation loc, V<ast_identifier> name_identifier, AnyExprV default_value, AnyTypeV type_node)
+  Vertex(SrcLocation loc, V<ast_identifier> name_identifier, bool is_readonly, AnyExprV default_value, AnyTypeV type_node)
     : ASTOtherVararg(ast_struct_field, loc, {name_identifier})
-    , type_node(type_node), default_value(default_value) {}
+    , is_readonly(is_readonly), type_node(type_node), default_value(default_value) {}
 };
 
 template<>

tolk/lexer.cpp

@@ -382,6 +382,7 @@ struct ChunkIdentifierOrKeyword final : ChunkLexerBase {
         if (str == "builtin") return tok_builtin;
         break;
       case 8:
+        if (str == "readonly") return tok_readonly;
         if (str == "continue") return tok_continue;
         if (str == "operator") return tok_operator;
         break;