encoding.csv: generic serialization (#15097)

vlib/encoding/csv/to_struct_arr.v

@@ -0,0 +1,67 @@
+module csv
+
+import strconv
+
+// decode csv to struct
+pub fn decode<T>(data string) []T {
+	mut result := []T{}
+	if data == '' {
+		return result
+	}
+
+	mut parser := new_reader(data)
+	mut columns_names := []string{}
+	mut i := 0
+	for {
+		items := parser.read() or { break }
+		if i == 0 {
+			for val in items {
+				columns_names << val
+			}
+		} else {
+			mut t_val := T{}
+			$for field in T.fields {
+				col := get_column(field.name, columns_names)
+				if col > -1 && col < items.len {
+					$if field.typ is string {
+						t_val.$(field.name) = items[col]
+					} $else $if field.typ is int {
+						t_val.$(field.name) = items[col].int()
+					} $else $if field.typ is f32 {
+						t_val.$(field.name) = f32(strconv.atof64(items[col]) or { f32(0.0) })
+					} $else $if field.typ is f64 {
+						t_val.$(field.name) = strconv.atof64(items[col]) or { f64(0.0) }
+					} $else $if field.typ is bool {
+						t_val.$(field.name) = string_to_bool(items[col])
+					}
+				}
+			}
+			result << t_val
+		}
+		i++
+	}
+
+	return result
+}
+
+fn string_to_bool(val string) bool {
+	l_val := val.to_lower().trim_space()
+	i_val := val.int()
+	if l_val == 'true' {
+		return true
+	}
+	if i_val == 1 {
+		return true
+	}
+
+	return false
+}
+
+fn get_column(name string, columns []string) int {
+	for i, val in columns {
+		if val == name {
+			return i
+		}
+	}
+	return -1
+}