default struct vals

vlib/compiler/struct.v

@@ -131,7 +131,9 @@ fn (p mut Parser) struct_decl() {
 	}
 
 	mut did_gen_something := false
+	mut i := -1
 	for p.tok != .rcbr {
+		i++
 		if p.tok == .key_pub {
 			if is_pub_field {
 				p.error('structs can only have one `pub:`, all public fields have to be grouped')
@@ -205,6 +207,15 @@ fn (p mut Parser) struct_decl() {
 		if is_atomic {
 			p.next()
 		}
+		// `a int = 4`
+		if p.tok == .assign {
+			p.next()
+			def_val_type, expr := p.tmp_expr()
+			if def_val_type != field_type {
+				p.error('expected `$field_type` but got `$def_val_type`')
+			}
+			p.table.add_default_val(i, typ.name, expr)
+		}	
 		// [ATTR]
 		mut attr := ''
 		if p.tok == .lsbr {

vlib/compiler/table.v

@@ -105,6 +105,7 @@ mut:
 	is_c           bool // `C.FILE`
 	enum_vals []string
 	gen_types []string
+	default_vals []string // `struct Foo { bar int = 2 }`
 	// This field is used for types that are not defined yet but are known to exist.
 	// It allows having things like `fn (f Foo) bar()` before `Foo` is defined.
 	// This information is needed in the first pass.
@@ -441,6 +442,12 @@ fn (table mut Table) add_field(type_name, field_name, field_type string, is_mut
 	table.typesmap[type_name] = t
 }
 
+fn (table mut Table) add_default_val(idx int, type_name, val_expr string) {
+	mut t := table.typesmap[type_name]
+	t.default_vals[idx] = val_expr
+	table.typesmap[type_name] = t
+}
+
 fn (t &Type) has_field(name string) bool {
 	_ = t.find_field(name) or { return false }
 	return true