sum types

vlib/compiler/enum.v

@@ -21,18 +21,15 @@ fn (p mut Parser) enum_decl(no_name bool) {
 	if !p.builtin_mod && p.mod != 'main' {
 		enum_name = p.prepend_mod(enum_name)
 	}
-	// Skip empty enums
-	if !no_name && !p.first_pass() {
-		p.cgen.typedefs << 'typedef int $enum_name;'
-	}
 	p.fspace()
 	p.check(.lcbr)
 	mut val := 0
 	mut fields := []string
+	mut tuple_variants := []string
 	for p.tok == .name {
 		field := p.check_name()
-		if contains_capital(field) {
-			p.warn('enum values cannot contain uppercase letters, use snake_case instead')
+		if p.pass == .decl && p.tok != .lpar && contains_capital(field) {
+			p.warn('enum values cannot contain uppercase letters, use snake_case instead (`$field`)')
 		}
 		fields << field
 		name := '${mod_gen_name(p.mod)}__${enum_name}_$field'
@@ -59,6 +56,18 @@ fn (p mut Parser) enum_decl(no_name bool) {
 				p.error_with_token_index('only numbers are allowed in enum initializations', enum_assign_tidx)
 			}
 		}
+		// `BoolExpr(bool)`
+		else if p.tok == .lpar {
+			if !field[0].is_capital() {
+				p.error('sum types must be capitalized')
+			}
+			p.check(.lpar)
+			tuple_variants << p.get_type()
+			p.check(.rpar)
+			if p.pass == .main {
+				p.cgen.consts << '#define ${field}_type $val // LOL'
+			}
+		}
 		if p.pass == .main {
 			p.cgen.consts << '#define $name $val'
 		}
@@ -81,10 +90,25 @@ fn (p mut Parser) enum_decl(no_name bool) {
 		is_public: is_pub
 		is_flag: is_flag
 	}
+	p.table.tuple_variants[enum_name] = tuple_variants
 	if is_flag && !p.first_pass() {
 		p.gen_enum_flag_methods(mut T)
 	}
+	if p.pass == .decl {
 		p.table.register_type(T)
+	}
+	// Register `Expression` enum
+	if tuple_variants.len > 0 && p.pass == .main {
+		p.cgen.typedefs << 'typedef struct {
+void* obj;
+int typ;
+} $enum_name;
+'
+	}
+	// Skip empty enums
+	else if !no_name && !p.first_pass() {
+		p.cgen.typedefs << 'typedef int $enum_name;'
+	}
 	p.check(.rcbr)
 	p.fgen_nl()
 	p.fgen_nl()
@@ -106,3 +130,23 @@ fn (p mut Parser) check_enum_member_access() {
 	}
 }
 
+/*
+
+enum Expression {
+Boolean(bool),
+Integer(i32),
+}
+
+fn main() {
+    let expr = Expression::Integer(10);
+    let mut val = Expression::Boolean(true);
+    val = expr;
+    match val {
+        Expression::Integer(n) => println!("INT {}", n),
+        Expression::Boolean(b) => println!("BOOL {}", b),
+    }
+
+    //println!("HELLO {}", val);
+}
+*/
+

vlib/compiler/expression.v

@@ -343,6 +343,31 @@ fn (p mut Parser) name_expr() string {
 				// no need in `if color == Color.red`
 				p.warn('`${enum_type.name}.$val` is unnecessary, use `.$val`')
 			}
+			// `expr := Expr.BoolExpr(true)` =>
+			// `Expr expr = { .obj = true, .typ = BoolExpr_type };`
+			if val[0].is_capital() {
+				p.next()
+				p.check(.lpar)
+				//println('sum type $val name=$val')
+				// Find a corresponding tuple variant
+				// TODO slow, but this will be re-written anyway
+				mut idx := 0
+				for i, val_ in enum_type.enum_vals {
+					//println('f $field.name')
+					if val_ == val {
+						idx = i
+					}
+				}
+				q := p.table.tuple_variants[enum_type.name]
+				//println(q)
+				//println(q[idx])
+				arg_type := q[idx]
+				p.gen('($enum_type.name) { .obj = ($arg_type[]) { ')
+				p.bool_expression()
+				p.check(.rpar)
+				p.gen('}, .typ = ${val}_type }')
+				return enum_type.name
+			}
 			// println('enum val $val')
 			p.gen(mod_gen_name(enum_type.mod) + '__' + enum_type.name + '_' + val) // `color = main__Color_green`
 			p.next()

vlib/compiler/table.v

@@ -21,6 +21,7 @@ pub mut:
 	// names        []Name
 	max_field_len         map[string]int // for vfmt: max_field_len['Parser'] == 12
 	generic_struct_params map[string][]string
+	tuple_variants map[string][]string
 }
 
 struct VargAccess {

vlib/compiler/tests/enum_test.v

@@ -54,3 +54,48 @@ fn test_nums() {
 	d := Foo.d
 	assert d == -10
 }
+
+
+enum Expr {
+	BoolExpr(bool)
+	IntExpr(int)
+	//FloatExpr(int)
+}
+
+fn get_expr() Expr {
+	return Expr.IntExpr(10)
+
+}
+
+fn test_typed_enum() {
+	i := Expr.IntExpr(10)
+	expr := Expr.BoolExpr(true)
+	//println(i)
+	//if i == expr {
+
+	//}
+	println('done')
+	// expr = i
+	/*
+	match expr {
+		IntExpr(n)  { println('INT $n')  }
+		BoolExpr(b) { println('BOOL $b') }
+	}
+	*/
+}
+/*
+
+fn test_typed_enum() {
+	Expr i = { .obj = 10, .typ = IntExpr_type };
+	Expr expr = { .obj = true, .typ = BoolExpr_type };
+	//    val = expr;
+	if (expr.typ == IntExpr_type) {
+		int n = (int)expr.obj;
+		println('INT $n');
+	}
+	else if (expr.typ == BoolExpr_type) {
+		int b = (bool)expr.obj;
+		println('BOOL $b');
+	}
+}
+*/