toml: add reflection method (#12664)

vlib/toml/any.v

@@ -226,3 +226,36 @@ fn (a Any) value_(value Any, key []string) Any {
 		}
 	}
 }
+
+pub fn (a Any) reflect<T>() T {
+	mut reflected := T{}
+	$for field in T.fields {
+		$if field.typ is string {
+			reflected.$(field.name) = a.value(field.name).default_to('').string()
+		} $else $if field.typ is bool {
+			reflected.$(field.name) = a.value(field.name).default_to(false).bool()
+		} $else $if field.typ is int {
+			reflected.$(field.name) = a.value(field.name).default_to(0).int()
+		} $else $if field.typ is f32 {
+			reflected.$(field.name) = a.value(field.name).default_to(0.0).f32()
+		} $else $if field.typ is f64 {
+			reflected.$(field.name) = a.value(field.name).default_to(0.0).f64()
+		} $else $if field.typ is i64 {
+			reflected.$(field.name) = a.value(field.name).default_to(0).i64()
+		} $else $if field.typ is u64 {
+			reflected.$(field.name) = a.value(field.name).default_to(0).u64()
+		} $else $if field.typ is Any {
+			reflected.$(field.name) = a.value(field.name)
+		} $else $if field.typ is DateTime {
+			dt := DateTime{'0000-00-00T00:00:00.000'}
+			reflected.$(field.name) = a.value(field.name).default_to(dt).datetime()
+		} $else $if field.typ is Date {
+			da := Date{'0000-00-00'}
+			reflected.$(field.name) = a.value(field.name).default_to(da).date()
+		} $else $if field.typ is Time {
+			t := Time{'00:00:00.000'}
+			reflected.$(field.name) = a.value(field.name).default_to(t).time()
+		}
+	}
+	return reflected
+}

vlib/toml/tests/reflect_test.v

@@ -0,0 +1,50 @@
+import toml
+
+const toml_text = '# This TOML can reflect to a struct
+name = "Tom"
+age = 45
+height = 1.97
+
+birthday = 1980-04-23
+
+[bio]
+text = "Tom has done many great things"
+years_of_service = 5
+
+[config]
+data = [ 1, 2, 3 ]
+levels = { "info" = 1, "warn" = 2, "critical" = 3 }
+'
+
+struct Bio {
+	text             string
+	years_of_service int
+}
+
+struct User {
+	name     string
+	age      int
+	height   f64
+	birthday toml.Date
+
+	config toml.Any
+mut:
+	bio Bio
+}
+
+fn test_reflect() {
+	toml_doc := toml.parse(toml_text) or { panic(err) }
+
+	mut user := toml_doc.reflect<User>()
+	user.bio = toml_doc.value('bio').reflect<Bio>()
+
+	assert user.name == 'Tom'
+	assert user.age == 45
+	assert user.height == 1.97
+	assert user.birthday.str() == '1980-04-23'
+	assert user.bio.text == 'Tom has done many great things'
+	assert user.bio.years_of_service == 5
+
+	assert user.config.value('data[0]').int() == 1
+	assert user.config.value('levels.warn').int() == 2
+}

vlib/toml/toml.v

@@ -173,6 +173,10 @@ pub fn (d Doc) to_any() Any {
 	return ast_to_any(d.ast.table)
 }
 
+pub fn (d Doc) reflect<T>() T {
+	return d.to_any().reflect<T>()
+}
+
 // value queries a value from the TOML document.
 // `key` supports a small query syntax scheme:
 // Maps can be queried in "dotted" form e.g. `a.b.c`.