toml: add `encode<T>` and `decode<T>` (#13244)

vlib/toml/any.v

@@ -33,6 +33,41 @@ pub fn (a Any) string() string {
 	}
 }
 
+// to_toml returns `Any` as a TOML encoded value.
+pub fn (a Any) to_toml() string {
+	match a {
+		map[string]Any {
+			// TODO more format control?
+			return a.to_inline_toml()
+		}
+		[]Any {
+			return a.to_toml()
+		}
+		bool, f32, f64, i64, int, u64 {
+			return a.str().clone()
+		}
+		// NOTE if `.clone()` is not used here:
+		// string { return a as string }
+		// ... certain call-patterns to this function will cause a memory corruption.
+		// See `tests/toml_memory_corruption_test.v` for a matching regression test.
+		string {
+			return '"' + (a as string).clone() + '"'
+		}
+		DateTime {
+			return a.str().clone()
+		}
+		Date {
+			return a.str().clone()
+		}
+		Time {
+			return a.str().clone()
+		}
+		else {
+			return a.str().clone()
+		}
+	}
+}
+
 // int returns `Any` as an 32-bit integer.
 pub fn (a Any) int() int {
 	match a {
@@ -181,6 +216,35 @@ pub fn (m map[string]Any) as_strings() map[string]string {
 	return result
 }
 
+// to_toml returns the contents of the map
+// as a TOML encoded `string`.
+pub fn (m map[string]Any) to_toml() string {
+	mut toml_text := ''
+	for k, v in m {
+		mut key := k
+		if key.contains(' ') {
+			key = '"$key"'
+		}
+		toml_text += '$key = ' + v.to_toml() + '\n'
+	}
+	toml_text = toml_text.trim_right('\n')
+	return toml_text
+}
+
+// to_inline_toml returns the contents of the map
+// as an inline table encoded TOML `string`.
+pub fn (m map[string]Any) to_inline_toml() string {
+	mut toml_text := '{'
+	for k, v in m {
+		mut key := k
+		if key.contains(' ') {
+			key = '"$key"'
+		}
+		toml_text += ' $key = ' + v.to_toml() + ','
+	}
+	return toml_text + ' }'
+}
+
 // value queries a value from the array.
 // `key` supports a small query syntax scheme:
 // The array can be queried with `[0].b[1].[2]`.
@@ -200,6 +264,17 @@ pub fn (a []Any) as_strings() []string {
 	return sa
 }
 
+// to_toml returns the contents of the array
+// as a TOML encoded `string`.
+pub fn (a []Any) to_toml() string {
+	mut toml_text := '[\n'
+	for any in a {
+		toml_text += '  ' + any.to_toml() + ',\n'
+	}
+	toml_text = toml_text.trim_right(',\n')
+	return toml_text + '\n]'
+}
+
 // value queries a value from the `Any` type.
 // `key` supports a small query syntax scheme:
 // Maps can be queried in "dotted" form e.g. `a.b.c`.

vlib/toml/tests/encode_and_decode_test.v

@@ -0,0 +1,58 @@
+import toml
+
+enum JobTitle {
+	manager
+	executive
+	worker
+}
+
+struct Employee {
+pub mut:
+	name     string
+	age      int
+	salary   f32
+	is_human bool
+	title    JobTitle
+}
+
+fn (e Employee) to_toml() string {
+	mut mp := map[string]toml.Any{}
+	mp['name'] = toml.Any(e.name)
+	mp['age'] = toml.Any(e.age)
+	mp['salary'] = toml.Any(e.salary)
+	mp['is_human'] = toml.Any(e.is_human)
+	mp['title'] = toml.Any(int(e.title))
+	return mp.to_toml()
+}
+
+fn (mut e Employee) from_toml(any toml.Any) {
+	mp := any.as_map()
+	e.name = mp['name'] or { toml.Any('') }.string()
+	e.age = mp['age'] or { toml.Any(0) }.int()
+	e.salary = mp['salary'] or { toml.Any(0) }.f32()
+	e.is_human = mp['is_human'] or { toml.Any(false) }.bool()
+	e.title = JobTitle(mp['title'] or { toml.Any(0) }.int())
+}
+
+fn test_encode_and_decode() {
+	x := Employee{'Peter', 28, 95000.5, true, .worker}
+	s := toml.encode<Employee>(x)
+	eprintln('Employee x: $s')
+	assert s == r'name = "Peter"
+age = 28
+salary = 95000.5
+is_human = true
+title = 2'
+
+	y := toml.decode<Employee>(s) or {
+		println(err)
+		assert false
+		return
+	}
+	eprintln('Employee y: $y')
+	assert y.name == 'Peter'
+	assert y.age == 28
+	assert y.salary == 95000.5
+	assert y.is_human == true
+	assert y.title == .worker
+}

vlib/toml/toml.v

@@ -12,6 +12,20 @@ import toml.parser
 pub struct Null {
 }
 
+// decode decodes a TOML `string` into the target type `T`.
+pub fn decode<T>(toml_txt string) ?T {
+	doc := parse_text(toml_txt) ?
+	mut typ := T{}
+	typ.from_toml(doc.to_any())
+	return typ
+}
+
+// encode encodes the type `T` into a JSON string.
+// Currently encode expects the method `.to_toml()` exists on `T`.
+pub fn encode<T>(typ T) string {
+	return typ.to_toml()
+}
+
 // DateTime is the representation of an RFC 3339 datetime string.
 pub struct DateTime {
 	datetime string