hare

expr.ha (13784B)

---

 // SPDX-License-Identifier: MPL-2.0
 // (c) Hare authors <https://harelang.org>
 
 use hare::lex;
 
 // An identifier access expression.
 //
 // 	foo
 export type access_identifier = ident;
 
 // An index access expression.
 //
 // 	foo[0]
 export type access_index = struct {
 	object: *expr,
 	index: *expr,
 };
 
 // A struct field access expression.
 //
 // 	foo.bar
 export type access_field = struct {
 	object: *expr,
 	field: str,
 };
 
 // A tuple field access expression.
 //
 // 	foo.1
 export type access_tuple = struct {
 	object: *expr,
 	value: *expr,
 };
 
 // An access expression.
 export type access_expr = (access_identifier | access_index | access_field
 	| access_tuple);
 
 // An align expression.
 //
 // 	align(int)
 export type align_expr = *_type;
 
 // The form of an allocation expression.
 //
 // 	alloc(foo)    // OBJECT
 // 	alloc(foo...) // COPY
 export type alloc_form = enum {
 	OBJECT,
 	COPY,
 };
 
 // An allocation expression.
 //
 // 	alloc(foo)
 // 	alloc(foo...)
 // 	alloc(foo, bar)
 export type alloc_expr = struct {
 	init: *expr,
 	form: alloc_form,
 	capacity: nullable *expr,
 };
 
 // An append expression.
 //
 // 	append(foo, bar);
 // 	append(foo, bar...);
 // 	append(foo, [0...], bar);
 export type append_expr = struct {
 	object: *expr,
 	value: *expr,
 	length: nullable *expr,
 	variadic: bool,
 	is_static: bool,
 };
 
 // An assertion expression.
 //
 // 	assert(foo)
 // 	assert(foo, "error")
 // 	abort()
 // 	abort("error")
 export type assert_expr = struct {
 	cond: nullable *expr,
 	message: nullable *expr,
 	is_static: bool,
 };
 
 // An assignment expression.
 //
 // 	foo = bar
 export type assign_expr = struct {
 	op: (binarithm_op | void),
 	object: *expr,
 	value: *expr,
 };
 
 // A binary arithmetic operator
 export type binarithm_op = enum {
 	// TODO: Rehome this with the checked AST?
 
 	BAND,	// &
 	BOR,	// |
 	DIV,	// /
 	GT,	// >
 	GTEQ,	// >=
 	LAND,	// &&
 	LEQUAL,	// ==
 	LESS,	// <
 	LESSEQ,	// <=
 	LOR,	// ||
 	LSHIFT,	// <<
 	LXOR,	// ^^
 	MINUS,	// -
 	MODULO,	// %
 	NEQUAL,	// !=
 	PLUS,	// +
 	RSHIFT,	// >>
 	TIMES,	// *
 	BXOR,	// ^
 };
 
 // A binary arithmetic expression.
 //
 // 	foo * bar
 export type binarithm_expr = struct {
 	op: binarithm_op,
 	lvalue: *expr,
 	rvalue: *expr,
 };
 
 // A single variable biding.
 //
 // 	foo: int = bar
 // 	(foo, foo2): int = bar
 export type binding = struct {
 	name: (str | binding_unpack),
 	_type: nullable *_type,
 	init: *expr,
 };
 
 // Tuple unpacking binding.
 //
 // 	(foo, _, bar)
 export type binding_unpack = [](str | void);
 
 // The kind of binding expression being used.
 export type binding_kind = enum {
 	CONST,
 	DEF,
 	LET,
 };
 
 // A variable binding expression.
 //
 // 	let foo: int = bar, ...
 export type binding_expr = struct {
 	is_static: bool,
 	kind: binding_kind,
 	bindings: []binding,
 };
 
 // A break expression. The label is set to empty string if absent.
 //
 // 	break :label
 export type break_expr = label;
 
 // A function call expression.
 //
 // 	foo(bar)
 export type call_expr = struct {
 	lvalue: *expr,
 	variadic: bool,
 	args: []*expr,
 };
 
 // The kind of cast expression being used.
 export type cast_kind = enum {
 	// TODO: Should this be rehomed with the checked AST?
 
 	CAST,
 	ASSERTION,
 	TEST,
 };
 
 // A cast expression.
 //
 // 	foo: int
 // 	foo as int
 // 	foo is int
 export type cast_expr = struct {
 	kind: cast_kind,
 	value: *expr,
 	_type: *_type,
 };
 
 // A compound expression.
 //
 // 	{
 // 		foo;
 // 		bar;
 // 		// ...
 // 	}
 export type compound_expr = struct {
 	exprs: []*expr,
 	label: label,
 };
 
 // An array literal.
 //
 // 	[foo, bar, ...]
 export type array_literal = struct {
 	expand: bool,
 	values: []*expr,
 };
 
 // A single struct field and value.
 //
 // 	foo: int = 10
 export type struct_value = struct {
 	name: str,
 	_type: nullable *_type,
 	init: *expr,
 };
 
 // A struct literal.
 //
 // 	struct { foo: int = bar, struct { baz = quux }, ... }
 export type struct_literal = struct {
 	autofill: bool,
 	alias: ident, // [] for anonymous
 	fields: [](struct_value | *struct_literal),
 };
 
 // A tuple literal.
 //
 // 	(foo, bar, ...)
 export type tuple_literal = []*expr;
 
 // The value "null".
 export type _null = void;
 
 // A scalar value.
 export type value = (bool | done | _null | str | rune | void);
 
 // An integer or float literal.
 export type number_literal = struct {
 	suff: lex::ltok,
 	value: (i64 | u64 | f64),
 	sign: bool, // true if negative, false otherwise
 };
 
 // A literal expression.
 export type literal_expr = (value | array_literal | number_literal |
 	struct_literal | tuple_literal);
 
 // A continue expression. The label is set to empty string if absent.
 //
 // 	continue :label
 export type continue_expr = label;
 
 // A deferred expression.
 //
 // 	defer foo
 export type defer_expr = *expr;
 
 // A delete expression.
 //
 // 	delete(foo[10])
 // 	delete(foo[4..42])
 export type delete_expr = struct {
 	object: *expr,
 	is_static: bool,
 };
 
 // The kind of for expression being used.
 export type for_kind = enum {
 	ACCUMULATOR,
 	EACH_VALUE,
 	EACH_POINTER,
 	ITERATOR,
 };
 
 // A for loop.
 //
 // 	for (let foo = 0; foo < bar; baz) quux
 // 	for (let line => next_line()) quux
 // 	for (let number .. [1, 2, 3]) quux
 // 	for (let ptr &.. [1, 2, 3]) quux
 export type for_expr = struct {
 	kind: for_kind,
 	bindings: nullable *expr,
 	cond: nullable *expr,
 	afterthought: nullable *expr,
 	body: *expr,
 	label: label,
 };
 
 // A free expression.
 //
 // 	free(foo)
 export type free_expr = *expr;
 
 // An if or if..else expression.
 //
 // 	if (foo) bar else baz
 export type if_expr = struct {
 	cond: *expr,
 	tbranch: *expr,
 	fbranch: nullable *expr,
 };
 
 // An insert expression.
 //
 // 	insert(foo[0], bar);
 // 	insert(foo[0], bar...);
 // 	insert(foo[0], [0...], bar);
 export type insert_expr = append_expr;
 
 // :label. The ":" character is not included.
 export type label = str;
 
 // A length expression.
 //
 // 	len(foo)
 export type len_expr = *expr;
 
 // A match case.
 //
 //	case type => exprs
 //	case let name: type => exprs
 export type match_case = struct {
 	name: str,
 	_type: nullable *_type, // null for default case
 	exprs: []*expr,
 };
 
 // A match expression.
 //
 // 	match (foo) { case int => bar; ... }
 export type match_expr = struct {
 	value: *expr,
 	cases: []match_case,
 	label: label,
 };
 
 // An offset expression.
 //
 // 	offset(foo.bar)
 export type offset_expr = *expr;
 
 // An error propagation expression.
 //
 // 	foo?
 export type propagate_expr = *expr;
 
 // An error assertion expression.
 //
 // 	foo!
 export type error_assert_expr = *expr;
 
 // A return statement.
 //
 // 	return foo
 export type return_expr = nullable *expr;
 
 // A size expression.
 //
 // 	size(int)
 export type size_expr = *_type;
 
 // A slicing expression.
 //
 // 	foo[bar..baz]
 export type slice_expr = struct {
 	object: *expr,
 	start: nullable *expr,
 	end: nullable *expr,
 };
 
 // A switch case.
 //
 // 	case value => exprs
 export type switch_case = struct {
 	options: []*expr, // [] for default case
 	exprs: []*expr,
 };
 
 // A switch expression.
 //
 // 	switch (foo) { case bar => baz; ... }
 export type switch_expr = struct {
 	value: *expr,
 	cases: []switch_case,
 	label: label,
 };
 
 // A unary operator
 export type unarithm_op = enum {
 	// TODO: Should this be rehomed with the checked AST?
 
 	ADDR,	// &
 	BNOT,	// ~
 	DEREF,	// *
 	LNOT,	// !
 	MINUS,	// -
 };
 
 // A unary arithmetic expression.
 //
 // 	!example
 export type unarithm_expr = struct {
 	op: unarithm_op,
 	operand: *expr,
 };
 
 // A vastart expression.
 //
 // 	vastart()
 export type vastart_expr = void;
 
 // A vaarg expression.
 //
 // 	vaarg(ap)
 export type vaarg_expr = *expr;
 
 // A vaend expression.
 //
 // 	vaend(ap)
 export type vaend_expr = *expr;
 
 // A C-style variadic expression.
 export type variadic_expr = (vastart_expr | vaarg_expr | vaend_expr);
 
 // A yield expression.
 //
 // 	yield foo
 export type yield_expr = struct {
 	label: label,
 	value: nullable *expr,
 };
 
 // A Hare expression.
 export type expr = struct {
 	start: lex::location,
 	end: lex::location,
 	expr: (access_expr | align_expr | alloc_expr | append_expr |
 		assert_expr | assign_expr | binarithm_expr | binding_expr |
 		break_expr | call_expr | cast_expr | literal_expr |
 		continue_expr | defer_expr | delete_expr | for_expr |
 		free_expr | error_assert_expr | if_expr | insert_expr |
 		compound_expr | match_expr | len_expr | size_expr |
 		offset_expr | propagate_expr | return_expr | slice_expr |
 		switch_expr | unarithm_expr | variadic_expr | yield_expr),
 };
 
 // Frees resources associated with a Hare [[expr]]ession.
 export fn expr_finish(e: nullable *expr) void = match (e) {
 case null => void;
 case let e: *expr =>
 	match (e.expr) {
 	case let a: access_expr =>
 		match (a) {
 		case let i: access_identifier =>
 			ident_free(i);
 		case let i: access_index =>
 			expr_finish(i.object);
 			free(i.object);
 			expr_finish(i.index);
 			free(i.index);
 		case let f: access_field =>
 			expr_finish(f.object);
 			free(f.object);
 			free(f.field);
 		case let t: access_tuple =>
 			expr_finish(t.object);
 			free(t.object);
 			expr_finish(t.value);
 			free(t.value);
 		};
 	case let a: align_expr =>
 		type_finish(a);
 		free(a);
 	case let a: alloc_expr =>
 		expr_finish(a.init);
 		free(a.init);
 		expr_finish(a.capacity);
 		free(a.capacity);
 	case let a: append_expr =>
 		expr_finish(a.object);
 		free(a.object);
 		expr_finish(a.value);
 		free(a.value);
 		expr_finish(a.length);
 		free(a.length);
 	case let a: assert_expr =>
 		expr_finish(a.cond);
 		free(a.cond);
 		expr_finish(a.message);
 		free(a.message);
 	case let a: assign_expr =>
 		expr_finish(a.object);
 		free(a.object);
 		expr_finish(a.value);
 		free(a.value);
 	case let b: binarithm_expr =>
 		expr_finish(b.lvalue);
 		free(b.lvalue);
 		expr_finish(b.rvalue);
 		free(b.rvalue);
 	case let b: binding_expr =>
 		for (let i = 0z; i < len(b.bindings); i += 1) {
 			match (b.bindings[i].name) {
 			case let s: str =>
 				free(s);
 			case let u: binding_unpack =>
 				for (let i = 0z; i < len(u); i += 1) {
 					match (u[i]) {
 					case let s: str =>
 						free(s);
 					case => void;
 					};
 				};
 				free(u);
 			};
 			type_finish(b.bindings[i]._type);
 			free(b.bindings[i]._type);
 			expr_finish(b.bindings[i].init);
 			free(b.bindings[i].init);
 		};
 		free(b.bindings);
 	case let b: break_expr =>
 		free(b);
 	case let c: call_expr =>
 		expr_finish(c.lvalue);
 		free(c.lvalue);
 		for (let i = 0z; i < len(c.args); i += 1) {
 			expr_finish(c.args[i]);
 			free(c.args[i]);
 		};
 		free(c.args);
 	case let c: cast_expr =>
 		expr_finish(c.value);
 		free(c.value);
 		type_finish(c._type);
 		free(c._type);
 	case let c: compound_expr =>
 		for (let i = 0z; i < len(c.exprs); i += 1) {
 			expr_finish(c.exprs[i]);
 			free(c.exprs[i]);
 		};
 		free(c.exprs);
 		free(c.label);
 	case let c: literal_expr =>
 		match (c) {
 		case let a: array_literal =>
 			for (let i = 0z; i < len(a.values); i += 1) {
 				expr_finish(a.values[i]);
 				free(a.values[i]);
 			};
 			free(a.values);
 		case let s: struct_literal =>
 			struct_literal_finish(&s);
 		case let t: tuple_literal =>
 			for (let i = 0z; i < len(t); i += 1) {
 				expr_finish(t[i]);
 				free(t[i]);
 			};
 			free(t);
 		case (value | number_literal) => void;
 		};
 	case let c: continue_expr =>
 		free(c);
 	case let d: defer_expr =>
 		expr_finish(d);
 		free(d);
 	case let d: delete_expr =>
 		expr_finish(d.object);
 		free(d.object);
 	case let e: error_assert_expr =>
 		expr_finish(e);
 		free(e);
 	case let f: for_expr =>
 		expr_finish(f.bindings);
 		free(f.bindings);
 		expr_finish(f.cond);
 		free(f.cond);
 		expr_finish(f.afterthought);
 		free(f.afterthought);
 		expr_finish(f.body);
 		free(f.body);
 	case let f: free_expr =>
 		expr_finish(f);
 		free(f);
 	case let i: if_expr =>
 		expr_finish(i.cond);
 		free(i.cond);
 		expr_finish(i.tbranch);
 		free(i.tbranch);
 		expr_finish(i.fbranch);
 		free(i.fbranch);
 	case let e: insert_expr =>
 		expr_finish(e.object);
 		free(e.object);
 		expr_finish(e.value);
 		free(e.value);
 		expr_finish(e.length);
 		free(e.length);
 	case let l: len_expr =>
 		expr_finish(l);
 		free(l);
 	case let m: match_expr =>
 		free(m.label);
 		expr_finish(m.value);
 		free(m.value);
 		for (let i = 0z; i < len(m.cases); i += 1) {
 			free(m.cases[i].name);
 			type_finish(m.cases[i]._type);
 			free(m.cases[i]._type);
 			const exprs = m.cases[i].exprs;
 			for (let i = 0z; i < len(exprs); i += 1) {
 				expr_finish(exprs[i]);
 				free(exprs[i]);
 			};
 			free(exprs);
 		};
 		free(m.cases);
 	case let o: offset_expr =>
 		expr_finish(o);
 		free(o);
 	case let p: propagate_expr =>
 		expr_finish(p);
 		free(p);
 	case let r: return_expr =>
 		expr_finish(r);
 		free(r);
 	case let s: size_expr =>
 		type_finish(s);
 		free(s);
 	case let s: slice_expr =>
 		expr_finish(s.object);
 		free(s.object);
 		expr_finish(s.start);
 		free(s.start);
 		expr_finish(s.end);
 		free(s.end);
 	case let s: switch_expr =>
 		free(s.label);
 		expr_finish(s.value);
 		free(s.value);
 		for (let i = 0z; i < len(s.cases); i += 1) {
 			let opts = s.cases[i].options;
 			for (let j = 0z; j < len(opts); j += 1) {
 				expr_finish(opts[j]);
 				free(opts[j]);
 			};
 			free(opts);
 
 			let exprs = s.cases[i].exprs;
 			for (let j = 0z; j < len(exprs); j += 1) {
 				expr_finish(exprs[j]);
 				free(exprs[j]);
 			};
 			free(exprs);
 		};
 		free(s.cases);
 	case let u: unarithm_expr =>
 		expr_finish(u.operand);
 		free(u.operand);
 	case let v: variadic_expr =>
 		match (v) {
 		case vastart_expr => void;
 		case let v: vaarg_expr =>
 			expr_finish(v);
 			free(v);
 		case let v: vaend_expr =>
 			expr_finish(v);
 			free(v);
 		};
 	case let y: yield_expr =>
 		free(y.label);
 		expr_finish(y.value);
 		free(y.value);
 	};
 };
 
 fn struct_literal_finish(s: *struct_literal) void = {
 	ident_free(s.alias);
 	for (let i = 0z; i < len(s.fields); i += 1) {
 		match (s.fields[i]) {
 		case let v: struct_value =>
 			free(v.name);
 			type_finish(v._type);
 			free(v._type);
 			expr_finish(v.init);
 			free(v.init);
 		case let c: *struct_literal =>
 			struct_literal_finish(c);
 			free(c);
 		};
 	};
 	free(s.fields);
 };