mirror of
https://github.com/clap-rs/clap
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92 lines
2.8 KiB
Rust
92 lines
2.8 KiB
Rust
// Copyright 2018 Guillaume Pinot (@TeXitoi) <texitoi@texitoi.eu>,
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// Kevin Knapp (@kbknapp) <kbknapp@gmail.com>, and
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// Andrew Hobden (@hoverbear) <andrew@hoverbear.org>
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*
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use proc_macro2;
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use quote;
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use syn;
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use syn::punctuated;
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use syn::token;
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pub fn derive_arg_enum(_ast: &syn::DeriveInput) -> proc_macro2::TokenStream {
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let from_str_block = impl_from_str(ast)?;
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let variants_block = impl_variants(ast)?;
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quote! {
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#from_str_block
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#variants_block
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}
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}
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fn impl_from_str(ast: &syn::DeriveInput) -> proc_macro2::TokenStream {
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let ident = &ast.ident;
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let is_case_sensitive = ast.attrs.iter().any(|v| v.name() == "case_sensitive");
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let variants = variants(ast)?;
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let strings = variants
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.iter()
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.map(|ref variant| String::from(variant.ident.as_ref()))
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.collect::<Vec<_>>();
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// All of these need to be iterators.
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let ident_slice = [ident.clone()];
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let idents = ident_slice.iter().cycle();
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let for_error_message = strings.clone();
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let condition_function_slice = [match is_case_sensitive {
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true => quote! { str::eq },
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false => quote! { ::std::ascii::AsciiExt::eq_ignore_ascii_case },
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}];
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let condition_function = condition_function_slice.iter().cycle();
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Ok(quote! {
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impl ::std::str::FromStr for #ident {
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type Err = String;
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fn from_str(input: &str) -> ::std::result::Result<Self, Self::Err> {
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match input {
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#(val if #condition_function(val, #strings) => Ok(#idents::#variants),)*
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_ => Err({
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let v = #for_error_message;
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format!("valid values: {}",
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v.join(" ,"))
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}),
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}
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}
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}
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})
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}
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fn impl_variants(ast: &syn::DeriveInput) -> proc_macro2::TokenStream {
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let ident = &ast.ident;
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let variants = variants(ast)?
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.iter()
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.map(|ref variant| String::from(variant.ident.as_ref()))
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.collect::<Vec<_>>();
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let length = variants.len();
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Ok(quote! {
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impl #ident {
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fn variants() -> [&'static str; #length] {
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#variants
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}
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}
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})
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}
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fn variants(ast: &syn::DeriveInput) -> &punctuated::Punctuated<syn::Variant, token::Comma> {
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use syn::Data::*;
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match ast.data {
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Enum(ref data) => data.variants,
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_ => panic!("Only enums are supported for deriving the ArgEnum trait"),
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}
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}
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*/
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