fix: Changed block expression syntax

`<{ ... }` to `from { ... }`

Because `<{ ... }` was ambiguous with a type value of map `<{K: V}>`

CHANGELOG.md

@@ -29,7 +29,7 @@ const person = Person {
 - Sandboxing build options `memory_limit` and `cycle_limit` (https://github.com/buzz-language/buzz/issues/182)
 - Block expression (https://github.com/buzz-language/buzz/issues/105):
 ```buzz
-var value = <{
+var value = from {
     | ... 
 
     out result;
@@ -41,6 +41,7 @@ var value = <{
 - Map type notation has changed from `{K, V}` to `{K: V}`. Similarly map expression with specified typed went from `{<K, V>, ...}` to `{<K: V>, ...}` (https://github.com/buzz-language/buzz/issues/253)
 - `File.readLine`, `File.readAll`, `Socket.readLine`, `Socket.readAll` have now an optional `maxSize` argument
 - Tail call optimization (https://github.com/buzz-language/buzz/issues/9). The effect should be limited for recursive calls since the JIT should kick in pretty quickly in those use cases.
+- Empty list and map without a specified type resolve to `[any]`/`{any: any}` unless the variable declaration context provides the type (https://github.com/buzz-language/buzz/issues/86)
 
 ## Fixed
 

src/Parser.zig

@@ -323,7 +323,7 @@ const rules = [_]ParseRule{
     .{ .prefix = null, .infix = null, .precedence = .None }, // Export
     .{ .prefix = null, .infix = null, .precedence = .None }, // Const
     .{ .prefix = null, .infix = null, .precedence = .None }, // Static
-    .{ .prefix = null, .infix = null, .precedence = .None }, // From
+    .{ .prefix = blockExpression, .infix = null, .precedence = .None }, // From
     .{ .prefix = null, .infix = null, .precedence = .None }, // As
     .{ .prefix = null, .infix = as, .precedence = .IsAs }, // AsQuestion
     .{ .prefix = null, .infix = null, .precedence = .None }, // Extern
@@ -343,7 +343,6 @@ const rules = [_]ParseRule{
     .{ .prefix = null, .infix = null, .precedence = .None }, // zdef
     .{ .prefix = typeOfExpression, .infix = null, .precedence = .Unary }, // typeof
     .{ .prefix = null, .infix = null, .precedence = .None }, // var
-    .{ .prefix = blockExpression, .infix = null, .precedence = .None }, // <{
     .{ .prefix = null, .infix = null, .precedence = .None }, // out
 };
 
@@ -5389,6 +5388,8 @@ fn typeOfExpression(self: *Self, _: bool) Error!Ast.Node.Index {
 fn blockExpression(self: *Self, _: bool) Error!Ast.Node.Index {
     const start_location = self.current_token.? - 1;
 
+    try self.consume(.LeftBrace, "Expected `{` at start of block expression");
+
     self.beginScope();
     self.current.?.in_block_expression = self.current.?.scope_depth;
 

src/Token.zig

@@ -175,7 +175,6 @@ pub const Type = enum {
     Zdef, // zdef
     TypeOf, // typeof
     Var, // var
-    Blk, // <{
     Out, // out
 };
 

src/scanner.zig

@@ -92,8 +92,6 @@ pub const Scanner = struct {
                 self.makeToken(.ShiftLeft, null, null, null)
             else if (self.match('='))
                 self.makeToken(.LessEqual, null, null, null)
-            else if (self.match('{'))
-                self.makeToken(.Blk, null, null, null)
             else
                 self.makeToken(.Less, null, null, null),
             '~' => self.makeToken(.Bnot, null, null, null),
@@ -688,7 +686,6 @@ pub const Scanner = struct {
                         .Arrow,
                         .Ampersand,
                         .Spread,
-                        .Blk,
                         => if (true_color) Color.punctuation else Color.magenta,
                         .IntegerValue,
                         .FloatValue,

tests/004-lists.buzz

@@ -57,4 +57,14 @@ test "list.clone" {
     foreach (int i, int el in copy) {
         assert(list[i] == el, message: "Could clone list");
     }
+}
+
+test "empty list type inferring" {
+    var list = [];
+
+    assert(typeof list == <[any]>);
+
+    [str] slist = [];
+
+    assert(typeof slist == <[str]>);
 }

tests/005-maps.buzz

@@ -83,4 +83,14 @@ test "map.clone" {
     foreach (str key, int value in copy) {
         assert(first[key] == value, message: "Could clone map");
     }
+}
+
+test "empty map type inferring" {
+    var map = {};
+
+    assert(typeof map == <{any: any}>);
+
+    {str: int} smap = {};
+
+    assert(typeof smap == <{str: int}>);
 }

tests/070-block-expression.buzz

@@ -1,7 +1,7 @@
 import "std";
 
 test "block expression" {
-    var value = <{
+    var value = from {
         print("doing stuff in my block...");
 
         out "my value";

tests/compile_errors/025-multiple-out.buzz

@@ -1,6 +1,6 @@
 | Only one `out` statement is allowed in block expression
 test "multiple out statements" {
-    <{
+    from {
         out "one";
         out "two";
     };

tests/compile_errors/026-out-last-statement.buzz

@@ -1,6 +1,6 @@
 | Last block expression statement must be `out`
 test "out must be last statement" {
-    <{
+    from {
         out "i should be last";
 
         "hello world";