refactor and reorganize code modules

lib/core/code/write.v

@@ -0,0 +1,70 @@
+module code
+
+pub struct WriteCode {
+	destination string
+}
+
+@[params]
+pub struct WriteOptions {
+pub:
+	format    bool
+	overwrite bool
+	document  bool
+	prefix    string
+	compile bool // whether to compile the written code
+	test bool // whether to test the written code
+}
+
+
+interface ICodeItem {
+	vgen() string
+}
+
+pub fn vgen(code []CodeItem) string {
+	mut str := ''
+	for item in code {
+		if item is Function {
+			str += '\n${item.vgen()}'
+		}
+		if item is Struct {
+			str += '\n${item.vgen()}'
+		}
+		if item is Interface {
+			str += '\n${item.vgen()}'
+		}
+		if item is CustomCode {
+			str += '\n${item.vgen()}'
+		}
+	}
+	return str
+}
+
+// pub fn (code Code) vgen() string {
+// 	return code.items.map(it.vgen()).join_lines()
+// }
+
+// vgen_import generates an import statement for a given type
+pub fn (import_ Import) vgen() string {
+	types_str := if import_.types.len > 0 {
+		'{${import_.types.join(', ')}}'
+	} else {
+		''
+	} // comma separated string list of  types
+	return 'import ${import_.mod} ${types_str}'
+}
+
+
+pub fn vgen_generics(generics map[string]string) string {
+	if generics.keys().len == 0 {
+		return ''
+	}
+	mut vstr := '['
+	for key, val in generics {
+		vstr += if val != '' { val } else { key }
+	}
+	return '${vstr}]'
+}
+
+pub fn (custom CustomCode) vgen() string {
+	return custom.text
+}