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#![allow(unused_imports)]
#![allow(unused_variables)]
extern crate syn;
use proc_macro2::TokenStream;
use quote::{quote, ToTokens};
use syn::visit::{self, Visit};
use syn::{DataStruct, File, GenericArgument, ItemFn, ItemStruct, Token};
struct StructVisitor {
pub struct_defs: Vec<StructDef>,
}
impl Default for StructVisitor {
fn default() -> Self {
StructVisitor {
struct_defs: Vec::new(),
}
}
}
impl<'ast> Visit<'ast> for StructVisitor {
fn visit_item_struct(&mut self, node: &'ast ItemStruct) {
let struct_name = node.ident.to_owned();
let mut struct_fields: Vec<StructField> = Vec::new();
let fields = node.fields.clone();
match fields {
syn::Fields::Named(names) => {
let names = names.named;
for field in names.iter() {
let field_name = field.ident.to_owned().unwrap().to_string();
match &field.ty {
syn::Type::Path(path) => {
let path = path.path.clone();
let mut segs = path.segments.into_iter();
let field_ty = segs.next().unwrap();
let field_ty_ident = field_ty.ident.to_owned().to_string();
if field_ty_ident == "Vec" {
let inner_ty = field_ty.arguments.to_owned();
match inner_ty {
syn::PathArguments::AngleBracketed(args) => {
let generic = args.args.last().unwrap();
if let GenericArgument::Type(ty) = generic {
match ty {
syn::Type::Path(path) => {
let path = path.path.to_owned();
let mut segs = path.segments.into_iter();
let inner_ty = segs.next().unwrap();
let inner_ty_ident =
inner_ty.ident.to_owned().to_string();
struct_fields.push(StructField {
name: field_name,
ty: Type::Vec(Box::new(Type::Atom(
inner_ty_ident,
))),
})
}
_ => panic!("The generic type is illegal!"),
}
} else {
panic!("The generic is not a type!")
}
}
_ => panic!("Not providing the Vec generic!"),
}
} else {
struct_fields.push(StructField {
name: field_name,
ty: Type::Atom(field_ty_ident),
});
}
}
_ => panic!("The field type is illegal!"),
}
}
}
_ => (),
};
self.struct_defs.push(StructDef {
name: struct_name.to_string(),
fields: struct_fields,
})
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum Type {
Vec(Box<Type>),
Atom(String),
}
#[derive(Debug, PartialEq, Eq)]
pub struct StructField {
pub name: String,
pub ty: Type,
}
#[derive(Debug, PartialEq, Eq)]
pub struct StructDef {
pub name: String,
pub fields: Vec<StructField>,
}
pub fn get_struct_defs_from_file(file: &File) -> Vec<StructDef> {
let mut visitor = StructVisitor::default();
visitor.visit_file(file);
visitor.struct_defs
}
pub fn get_struct_defs(token_stream: TokenStream) -> Vec<StructDef> {
let file: File = syn::parse2(token_stream).unwrap();
get_struct_defs_from_file(&file)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn get_struct_defs_one() {
let code = quote! {
struct Person {
name: String,
age: u8
}
};
let struct_defs = get_struct_defs(code);
let struct_def = struct_defs.first().unwrap();
assert_eq!(
*struct_def,
StructDef {
name: "Person".to_string(),
fields: vec![
StructField {
name: "name".to_string(),
ty: Type::Atom("String".to_string()),
},
StructField {
name: "age".to_string(),
ty: Type::Atom("u8".to_string()),
}
]
}
)
}
#[test]
fn get_struct_defs_multiple() {
let code = quote! {
struct Person {
name: String,
age: u8
}
struct Animal {
alive: bool
}
};
let struct_defs = get_struct_defs(code);
assert_eq!(
struct_defs,
vec![
StructDef {
name: "Person".to_string(),
fields: vec![
StructField {
name: "name".to_string(),
ty: Type::Atom("String".to_string()),
},
StructField {
name: "age".to_string(),
ty: Type::Atom("u8".to_string()),
}
]
},
StructDef {
name: "Animal".to_string(),
fields: vec![StructField {
name: "alive".to_string(),
ty: Type::Atom("bool".to_string()),
}]
}
]
)
}
#[test]
fn get_struct_def_vec() {
let code = quote! {
struct Student {
marks: Vec<u32>
}
};
let struct_defs = get_struct_defs(code);
assert_eq!(
struct_defs,
vec![StructDef {
name: "Student".to_string(),
fields: vec![StructField {
name: "marks".to_string(),
ty: Type::Vec(Box::new(Type::Atom("u32".to_string())))
}]
}]
)
}
}