plux-codegen 0.3.0

A code generator for plux-rs
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153

use proc_macro2::{Ident, TokenStream};
use quote::{format_ident, quote};
use syn::{GenericArgument, PathArguments, ReturnType, Type, TypePath};

use crate::function::utils::{clear_ref, get_literal_type};

pub(crate) fn generate_function(
    externals: &Vec<(Ident, &Type)>,
    inputs: &Vec<(Ident, &Type)>,
    output: &ReturnType,
    args: TokenStream,
    block: TokenStream,
) -> TokenStream {
    let exts = generate_exts(externals);
    let ins = generate_inputs(inputs);
    let call = function_call(exts, ins, output);
    let out = return_output(output);

    quote! {
        let func = move |#args| #output #block;
        #call
        #out
    }
}

fn generate_exts(externals: &Vec<(Ident, &Type)>) -> TokenStream {
    let exts: Vec<TokenStream> = externals
        .iter()
        .map(|(name, _)| {
            quote! { &self.#name }
        })
        .collect();

    quote! { (#(#exts), *) }
}

fn generate_inputs(inputs: &Vec<(Ident, &Type)>) -> TokenStream {
    let args: Vec<TokenStream> = inputs
        .iter()
        .enumerate()
        .map(|(index, (_, ty))| {
            let ty = clear_ref(*ty);
            let type_name = ty.path.segments.last().unwrap().ident.to_string();
            if type_name == "Variable" {
                quote! { &args[#index].clone() }
            } else {
                quote! { args[#index].try_parse_ref::<#ty>()? }
            }
        })
        .collect();

    quote! { #(#args), * }
}

fn function_call(exts: TokenStream, args: TokenStream, output: &ReturnType) -> TokenStream {
    let (output_token, question_token) = match output {
        syn::ReturnType::Default => (None, None),
        syn::ReturnType::Type(_, ty) => match ty.as_ref() {
            Type::Path(path) => match path.path.segments.last() {
                Some(segment) if segment.ident.to_string() == "Result" => (
                    match &segment.arguments {
                        PathArguments::AngleBracketed(args) => {
                            if let Some(GenericArgument::Type(ty)) = args.args.first() {
                                match ty {
                                    Type::Tuple(tuple) => (tuple.elems.len() == 0)
                                        .then(|| None)
                                        .unwrap_or_else(|| panic!("Wrong type")),
                                    _ => Some(quote! { let result = }),
                                }
                            } else {
                                None
                            }
                        }
                        _ => None,
                    },
                    Some(quote! { ? }),
                ),
                _ => (Some(quote! { let result = }), None),
            },
            _ => (None, None),
        },
    };

    quote! { #output_token func(#exts, #args)#question_token; }
}

fn return_output(output: &ReturnType) -> TokenStream {
    match output {
        syn::ReturnType::Default => quote! { Ok(None) },
        syn::ReturnType::Type(_, ty) => match ty.as_ref() {
            Type::Infer(_) | Type::Never(_) => quote! { Ok(None) },
            Type::Tuple(tuple) if tuple.elems.is_empty() => quote! { Ok(None) },
            Type::Path(path) => match path.path.segments.last() {
                Some(segment) if segment.ident == "Result" => match &segment.arguments {
                    PathArguments::AngleBracketed(args) => {
                        if let Some(GenericArgument::Type(ty)) = args.args.first() {
                            match ty {
                                Type::Tuple(tuple) => tuple
                                    .elems
                                    .is_empty()
                                    .then(|| quote! { Ok(None) })
                                    .unwrap_or_else(|| panic!("Wrong type")),
                                _ => {
                                    let result = serialize_output(get_literal_type(ty));
                                    quote! { Ok(Some(#result)) }
                                }
                            }
                        } else {
                            panic!("Wrong type")
                        }
                    }
                    _ => panic!("Wrong type"),
                },
                _ => {
                    let result = serialize_output(get_literal_type(ty.as_ref()));
                    quote! { Ok(Some(#result)) }
                }
            },
            _ => panic!("Wrong type"),
        },
    }
}

const VARIABLE_DATAS: [(&str, &str); 13] = [
    ("i8", "I8"),
    ("i16", "I16"),
    ("i32", "I32"),
    ("i64", "I64"),
    ("u8", "U8"),
    ("u16", "U16"),
    ("u32", "U32"),
    ("u64", "U64"),
    ("f32", "F32"),
    ("f64", "F64"),
    ("bool", "Bool"),
    ("char", "Char"),
    ("String", "String"),
];

fn serialize_output(ty: &TypePath) -> TokenStream {
    let type_name = ty.path.segments.last().unwrap().ident.to_string();

    if let Some((_, token)) = VARIABLE_DATAS.iter().find(|(name, _)| **name == type_name) {
        let token = format_ident!("{}", *token);
        quote! { plux_rs::variable::Variable::#token (result) }
    } else if type_name == "Vec" {
        quote! { plux_rs::variable::Variable::List(result.into_iter().map(|item| item.into()).collect()) }
    } else if type_name == "Variable" {
        quote! { result }
    } else {
        TokenStream::new()
    }
}