use std::iter::FromIterator;
use proc_macro_error::{abort, ResultExt};
use quote::ToTokens;
use syn::{
self, parenthesized,
parse::{Parse, ParseBuffer, ParseStream},
punctuated::Punctuated,
Attribute, Expr, ExprLit, Ident, Lit, LitBool, LitStr, Token,
};
#[allow(clippy::large_enum_variant)]
pub enum ClapAttr {
Short(Ident),
Long(Ident),
Env(Ident),
Flatten(Ident),
ArgEnum(Ident),
FromGlobal(Ident),
Subcommand(Ident),
VerbatimDocComment(Ident),
ExternalSubcommand(Ident),
About(Ident, Option<LitStr>),
Author(Ident, Option<LitStr>),
Version(Ident, Option<LitStr>),
DefaultValue(Ident, Option<LitStr>),
RenameAllEnv(Ident, LitStr),
RenameAll(Ident, LitStr),
NameLitStr(Ident, LitStr),
Parse(Ident, ParserSpec),
Skip(Ident, Option<Expr>),
NameExpr(Ident, Expr),
MethodCall(Ident, Vec<Expr>),
}
impl Parse for ClapAttr {
fn parse(input: ParseStream) -> syn::Result<Self> {
use self::ClapAttr::*;
let name: Ident = input.parse()?;
let name_str = name.to_string();
if input.peek(Token![=]) {
let assign_token = input.parse::<Token![=]>()?;
if input.peek(LitStr) {
let lit: LitStr = input.parse()?;
let lit_str = lit.value();
let check_empty_lit = |s| {
if lit_str.is_empty() {
abort!(
lit,
"`#[clap({} = \"\")` is deprecated, \
now it's default behavior",
s
);
}
};
match &*name_str {
"rename_all" => Ok(RenameAll(name, lit)),
"rename_all_env" => Ok(RenameAllEnv(name, lit)),
"default_value" => Ok(DefaultValue(name, Some(lit))),
"version" => {
check_empty_lit("version");
Ok(Version(name, Some(lit)))
}
"author" => {
check_empty_lit("author");
Ok(Author(name, Some(lit)))
}
"about" => {
check_empty_lit("about");
Ok(About(name, Some(lit)))
}
"skip" => {
let expr = ExprLit {
attrs: vec![],
lit: Lit::Str(lit),
};
let expr = Expr::Lit(expr);
Ok(Skip(name, Some(expr)))
}
_ => Ok(NameLitStr(name, lit)),
}
} else {
match input.parse::<Expr>() {
Ok(expr) => {
if name_str == "skip" {
Ok(Skip(name, Some(expr)))
} else {
Ok(NameExpr(name, expr))
}
}
Err(_) => abort! {
assign_token,
"expected `string literal` or `expression` after `=`"
},
}
}
} else if input.peek(syn::token::Paren) {
let nested;
parenthesized!(nested in input);
match name_str.as_ref() {
"parse" => {
let parser_specs: Punctuated<ParserSpec, Token![,]> =
nested.parse_terminated(ParserSpec::parse)?;
if parser_specs.len() == 1 {
Ok(Parse(name, parser_specs[0].clone()))
} else {
abort!(name, "parse must have exactly one argument")
}
}
"raw" => match nested.parse::<LitBool>() {
Ok(bool_token) => {
let expr = ExprLit {
attrs: vec![],
lit: Lit::Bool(bool_token),
};
let expr = Expr::Lit(expr);
Ok(MethodCall(name, vec![expr]))
}
Err(_) => {
abort!(name,
"`#[clap(raw(...))` attributes are removed, \
they are replaced with raw methods";
help = "if you meant to call `clap::Arg::raw()` method \
you should use bool literal, like `raw(true)` or `raw(false)`";
note = raw_method_suggestion(nested);
);
}
},
_ => {
let method_args: Punctuated<_, Token![,]> =
nested.parse_terminated(Expr::parse)?;
Ok(MethodCall(name, Vec::from_iter(method_args)))
}
}
} else {
match name_str.as_ref() {
"long" => Ok(Long(name)),
"short" => Ok(Short(name)),
"env" => Ok(Env(name)),
"flatten" => Ok(Flatten(name)),
"arg_enum" => Ok(ArgEnum(name)),
"from_global" => Ok(FromGlobal(name)),
"subcommand" => Ok(Subcommand(name)),
"external_subcommand" => Ok(ExternalSubcommand(name)),
"verbatim_doc_comment" => Ok(VerbatimDocComment(name)),
"default_value" => Ok(DefaultValue(name, None)),
"about" => Ok(About(name, None)),
"author" => Ok(Author(name, None)),
"version" => Ok(Version(name, None)),
"skip" => Ok(Skip(name, None)),
_ => abort!(name, "unexpected attribute: {}", name_str),
}
}
}
}
#[derive(Clone)]
pub struct ParserSpec {
pub kind: Ident,
pub eq_token: Option<Token![=]>,
pub parse_func: Option<Expr>,
}
impl Parse for ParserSpec {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let kind = input
.parse()
.map_err(|_| input.error("parser specification must start with identifier"))?;
let eq_token = input.parse()?;
let parse_func = match eq_token {
None => None,
Some(_) => Some(input.parse()?),
};
Ok(ParserSpec {
kind,
eq_token,
parse_func,
})
}
}
fn raw_method_suggestion(ts: ParseBuffer) -> String {
let do_parse = move || -> Result<(Ident, Punctuated<Expr, Token![,]>), syn::Error> {
let name = ts.parse()?;
let _eq: Token![=] = ts.parse()?;
let val: LitStr = ts.parse()?;
let exprs = val.parse_with(Punctuated::<Expr, Token![,]>::parse_terminated)?;
Ok((name, exprs))
};
fn to_string<T: ToTokens>(val: &T) -> String {
val.to_token_stream()
.to_string()
.replace(" ", "")
.replace(",", ", ")
}
if let Ok((name, exprs)) = do_parse() {
let suggestion = if exprs.len() == 1 {
let val = to_string(&exprs[0]);
format!(" = {}", val)
} else {
let val = exprs
.into_iter()
.map(|expr| to_string(&expr))
.collect::<Vec<_>>()
.join(", ");
format!("({})", val)
};
format!(
"if you need to call `clap::Arg/App::{}` method you \
can do it like this: #[clap({}{})]",
name, name, suggestion
)
} else {
"if you need to call some method from `clap::Arg/App` \
you should use raw method, see \
https://docs.rs/structopt/0.3/structopt/#raw-methods"
.into()
}
}
pub fn parse_clap_attributes(all_attrs: &[Attribute]) -> Vec<ClapAttr> {
all_attrs
.iter()
.filter(|attr| attr.path.is_ident("clap"))
.flat_map(|attr| {
attr.parse_args_with(Punctuated::<ClapAttr, Token![,]>::parse_terminated)
.unwrap_or_abort()
})
.collect()
}