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|
use std::hash::Hash;
use proc_macro2::Span;
use syn::parse::{Parse, ParseStream};
use syn::{Ident, Lit, LitBool, Token};
use crate::util::error::diagnostic_error_enum;
#[derive(Debug, Clone)]
pub struct MacroFlag
{
pub name: Ident,
pub value: MacroFlagValue,
}
impl MacroFlag
{
pub fn new_off(flag: &str) -> Self
{
Self {
name: Ident::new(flag, Span::call_site()),
value: MacroFlagValue::Literal(Lit::Bool(LitBool::new(
false,
Span::call_site(),
))),
}
}
pub fn name(&self) -> &Ident
{
&self.name
}
pub fn get_bool(&self) -> Result<bool, MacroFlagError>
{
if let MacroFlagValue::Literal(Lit::Bool(lit_bool)) = &self.value {
return Ok(lit_bool.value);
}
Err(MacroFlagError::UnexpectedValueKind {
expected: "boolean literal",
value_span: self.value.span(),
})
}
pub fn get_ident(&self) -> Result<Ident, MacroFlagError>
{
if let MacroFlagValue::Identifier(ident) = &self.value {
return Ok(ident.clone());
}
Err(MacroFlagError::UnexpectedValueKind {
expected: "identifier",
value_span: self.value.span(),
})
}
}
impl Parse for MacroFlag
{
fn parse(input: ParseStream) -> syn::Result<Self>
{
let name = input.parse::<Ident>()?;
input.parse::<Token![=]>()?;
let value: MacroFlagValue = input.parse()?;
Ok(Self { name, value })
}
}
impl PartialEq for MacroFlag
{
fn eq(&self, other: &Self) -> bool
{
self.name == other.name
}
}
impl Eq for MacroFlag {}
impl Hash for MacroFlag
{
fn hash<H: std::hash::Hasher>(&self, state: &mut H)
{
self.name.hash(state);
}
}
diagnostic_error_enum! {
pub enum MacroFlagError {
#[error("Expected a {expected}"), span = value_span]
UnexpectedValueKind {
expected: &'static str,
value_span: Span
},
}
}
#[derive(Debug, Clone)]
pub enum MacroFlagValue
{
Literal(Lit),
Identifier(Ident),
}
impl MacroFlagValue
{
fn span(&self) -> Span
{
match self {
Self::Literal(lit) => lit.span(),
Self::Identifier(ident) => ident.span(),
}
}
}
impl Parse for MacroFlagValue
{
fn parse(input: ParseStream) -> syn::Result<Self>
{
if let Ok(lit) = input.parse::<Lit>() {
return Ok(Self::Literal(lit));
};
input.parse::<Ident>().map(Self::Identifier).map_err(|err| {
syn::Error::new(err.span(), "Expected a literal or a identifier")
})
}
}
#[cfg(test)]
mod tests
{
use std::error::Error;
use proc_macro2::Span;
use quote::{format_ident, quote};
use syn::parse2;
use super::*;
#[test]
fn can_parse_macro_flag() -> Result<(), Box<dyn Error>>
{
assert_eq!(
parse2::<MacroFlag>(quote! {
more = true
})?,
MacroFlag {
name: format_ident!("more"),
value: MacroFlagValue::Literal(Lit::Bool(LitBool::new(
true,
Span::call_site()
)))
}
);
assert_eq!(
parse2::<MacroFlag>(quote! {
do_something = false
})?,
MacroFlag {
name: format_ident!("do_something"),
value: MacroFlagValue::Literal(Lit::Bool(LitBool::new(
false,
Span::call_site()
)))
}
);
assert!(parse2::<MacroFlag>(quote! {
10 = false
})
.is_err());
Ok(())
}
}
|
