Remove specialization hacks for PopArgument and SlashArgument

macros/src/command/mod.rs

@@ -79,6 +79,7 @@ struct ParamArgs {
     max: Option<syn::Lit>,
     min_length: Option<syn::Lit>,
     max_length: Option<syn::Lit>,
+    string: bool,
     lazy: bool,
     flag: bool,
     rest: bool,

macros/src/command/prefix.rs

@@ -8,12 +8,14 @@ fn quote_parameter(p: &super::CommandParameter) -> Result<proc_macro2::TokenStre
         Lazy,
         Flag,
         Rest,
+        String,
     }
-    let modifier = match (p.args.lazy, p.args.rest, p.args.flag) {
-        (false, false, false) => Modifier::None,
-        (true, false, false) => Modifier::Lazy,
-        (false, true, false) => Modifier::Rest,
-        (false, false, true) => Modifier::Flag,
+    let modifier = match (p.args.lazy, p.args.rest, p.args.flag, p.args.string) {
+        (false, false, false, false) => Modifier::None,
+        (true, false, false, false) => Modifier::Lazy,
+        (false, true, false, false) => Modifier::Rest,
+        (false, false, true, false) => Modifier::Flag,
+        (false, false, false, true) => Modifier::String,
         _ => {
             let message = "modifiers like #[lazy] or #[rest] currently cannot be used together";
             return Err(syn::Error::new(p.span, message));
@@ -33,6 +35,7 @@ fn quote_parameter(p: &super::CommandParameter) -> Result<proc_macro2::TokenStre
         }
         Modifier::Lazy => quote::quote! { #[lazy] (#type_) },
         Modifier::Rest => quote::quote! { #[rest] (#type_) },
+        Modifier::String => quote::quote! { #[string] (#type_) },
         Modifier::None => quote::quote! { (#type_) },
     })
 }

macros/src/command/slash.rs

@@ -80,7 +80,7 @@ pub fn generate_parameters(inv: &Invocation) -> Result<Vec<proc_macro2::TokenStr
                     quote::quote! { Some(|o| o.kind(::poise::serenity_prelude::CommandOptionType::Integer)) }
                 } else {
                     quote::quote! { Some(|o| {
-                        poise::create_slash_argument!(#type_, o)
+                        <#type_ as ::poise::SlashArgument>::create(o)
                         #min_value_setter #max_value_setter
                         #min_length_setter #max_length_setter
                     }) }
@@ -101,7 +101,7 @@ pub fn generate_parameters(inv: &Invocation) -> Result<Vec<proc_macro2::TokenStr
                     __non_exhaustive: (),
                 } ),*]) }
             } else {
-                quote::quote! { poise::slash_argument_choices!(#type_) }
+                quote::quote! { <#type_ as ::poise::SlashArgument>::choices() }
             }
         } else {
             quote::quote! { Cow::Borrowed(&[]) }

macros/src/lib.rs

@@ -88,9 +88,10 @@ for example for command-specific help (i.e. `~help command_name`). Escape newlin
 SlashContext, which contain a variety of context data each. Context provides some utility methods to
 access data present in both PrefixContext and SlashContext, like `author()` or `created_at()`.
 
-All following parameters are inputs to the command. You can use all types that implement `poise::PopArgument`, `serenity::ArgumentConvert` or `std::str::FromStr`.
-You can also wrap types in `Option` or `Vec` to make them optional or variadic. In addition, there
-are multiple attributes you can use on parameters:
+All following parameters are inputs to the command. You can use all types that implement
+`PopArgument` (for prefix commands) or `SlashArgument` (for slash commands). You can also wrap
+types in `Option` or `Vec` to make them optional or variadic. In addition, there are multiple
+attributes you can use on parameters:
 
 ## Meta properties
 
@@ -109,6 +110,7 @@ are multiple attributes you can use on parameters:
 - `#[max_length = 1]`: Maximum length for this string parameter (slash-only)
 
 ## Parser settings (prefix only)
+- `#[string]`: Indicates that a type implements `FromStr` and should be parsed from a string argument.
 - `#[rest]`: Use the entire rest of the message for this parameter (prefix-only)
 - `#[lazy]`: Can be used on Option and Vec parameters and is equivalent to regular expressions' laziness (prefix-only)
 - `#[flag]`: Can be used on a bool parameter to set the bool to true if the user typed the parameter name literally (prefix-only)

src/choice_parameter.rs

@@ -1,7 +1,7 @@
 //! Contains the [`ChoiceParameter`] trait and the blanket [`crate::SlashArgument`] and
 //! [`crate::PopArgument`] impl
 
-use crate::{serenity_prelude as serenity, CowVec};
+use crate::{serenity_prelude as serenity, CowVec, PopArgumentResult};
 
 /// This trait is implemented by [`crate::macros::ChoiceParameter`]. See its docs for more
 /// information
@@ -62,10 +62,9 @@ impl<'a, T: ChoiceParameter> crate::PopArgument<'a> for T {
         attachment_index: usize,
         ctx: &serenity::Context,
         msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, Self), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>
-    {
+    ) -> PopArgumentResult<'a, Self> {
         let (args, attachment_index, s) =
-            crate::pop_prefix_argument!(String, args, attachment_index, ctx, msg).await?;
+            String::pop_from(args, attachment_index, ctx, msg).await?;
 
         Ok((
             args,

src/lib.rs

@@ -190,7 +190,7 @@ type Context<'a> = poise::Context<'a, Data, Error>;
 )]
 async fn my_huge_ass_command(
     ctx: Context<'_>,
-    #[description = "Consectetur"] ip_addr: std::net::IpAddr, // implements FromStr
+    #[description = "Consectetur"] #[string] ip_addr: std::net::IpAddr, // implements FromStr
     #[description = "Amet"] user: serenity::Member, // implements ArgumentConvert
     #[description = "Sit"] code_block: poise::CodeBlock, // implements PopArgument
     #[description = "Dolor"] #[flag] my_flag: bool,

src/prefix_argument/argument_trait.rs

@@ -1,106 +1,43 @@
-//! Trait implemented for all types usable as prefix command parameters. This file also includes
-//! the auto-deref specialization emulation code to e.g. support more strings for bool parameters
-//! instead of the `FromStr` ones
+//! Trait implemented for all types usable as prefix command parameters.
+//!
+//! Many of these implementations defer to [`serenity::ArgumentConvert`].
 
 use super::{pop_string, InvalidBool, MissingAttachment, TooFewArguments};
 use crate::serenity_prelude as serenity;
-use std::marker::PhantomData;
 
-/// Full version of [`crate::PopArgument::pop_from`].
-///
-/// Uses specialization to get full coverage of types. Pass the type as the first argument
-#[macro_export]
-macro_rules! pop_prefix_argument {
-    ($target:ty, $args:expr, $attachment_id:expr, $ctx:expr, $msg:expr) => {{
-        use $crate::PopArgumentHack as _;
-        (&std::marker::PhantomData::<$target>).pop_from($args, $attachment_id, $ctx, $msg)
-    }};
-}
+/// The result of [`PopArgument::pop_from`].
+///  - If Ok, this is `(remaining, attachment_index, T)`
+///  - If Err, this is `(error, failing_arg)`
+pub(crate) type PopArgumentResult<'a, T> =
+    Result<(&'a str, usize, T), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>;
 
 /// Parse a value out of a string by popping off the front of the string. Discord message context
 /// is available for parsing, and IO may be done as part of the parsing.
 ///
 /// Implementors should assume that a string never starts with whitespace, and fail to parse if it
-/// does. This is for consistency's
-/// sake and also because it keeps open the possibility of parsing whitespace.
+/// does. This is for consistency's sake and also because it keeps open the possibility of parsing
+/// whitespace.
 ///
 /// Similar in spirit to [`std::str::FromStr`].
 #[async_trait::async_trait]
 pub trait PopArgument<'a>: Sized {
-    /// Parse [`Self`] from the front of the given string and return a tuple of the remaining string
-    /// and [`Self`]. If parsing failed, an error is returned and, if applicable, the string on
-    /// which parsing failed.
-    ///
-    /// If parsing fails because the string is empty, use the `TooFewArguments` type as the error.
-    ///
-    /// Don't call this method directly! Use [`crate::pop_prefix_argument!`]
+    /// Pops an argument from the `args` string, and parses it as `Self`.
     async fn pop_from(
         args: &'a str,
         attachment_index: usize,
         ctx: &serenity::Context,
         msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, Self), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>;
+    ) -> PopArgumentResult<'a, Self>;
 }
 
-#[doc(hidden)]
 #[async_trait::async_trait]
-pub trait PopArgumentHack<'a, T>: Sized {
+impl<'a> PopArgument<'a> for bool {
     async fn pop_from(
-        self,
         args: &'a str,
         attachment_index: usize,
         ctx: &serenity::Context,
         msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, T), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>;
-}
-
-#[async_trait::async_trait]
-impl<'a, T: serenity::ArgumentConvert + Send> PopArgumentHack<'a, T> for PhantomData<T>
-where
-    T::Err: std::error::Error + Send + Sync + 'static,
-{
-    async fn pop_from(
-        self,
-        args: &'a str,
-        attachment_index: usize,
-        ctx: &serenity::Context,
-        msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, T), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>
-    {
-        let (args, string) =
-            pop_string(args).map_err(|_| (TooFewArguments::default().into(), None))?;
-        let object = T::convert(ctx, msg.guild_id, Some(msg.channel_id), &string)
-            .await
-            .map_err(|e| (e.into(), Some(string)))?;
-
-        Ok((args.trim_start(), attachment_index, object))
-    }
-}
-
-#[async_trait::async_trait]
-impl<'a, T: PopArgument<'a> + Send + Sync> PopArgumentHack<'a, T> for &PhantomData<T> {
-    async fn pop_from(
-        self,
-        args: &'a str,
-        attachment_index: usize,
-        ctx: &serenity::Context,
-        msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, T), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>
-    {
-        T::pop_from(args, attachment_index, ctx, msg).await
-    }
-}
-
-#[async_trait::async_trait]
-impl<'a> PopArgumentHack<'a, bool> for &PhantomData<bool> {
-    async fn pop_from(
-        self,
-        args: &'a str,
-        attachment_index: usize,
-        ctx: &serenity::Context,
-        msg: &serenity::Message,
-    ) -> Result<(&'a str, usize, bool), (Box<dyn std::error::Error + Send + Sync>, Option<String>)>
-    {
+    ) -> PopArgumentResult<'a, Self> {
         let (args, string) =
             pop_string(args).map_err(|_| (TooFewArguments::default().into(), None))?;
 
@@ -115,17 +52,13 @@ impl<'a> PopArgumentHack<'a, bool> for &PhantomData<bool> {
 }
 
 #[async_trait::async_trait]
-impl<'a> PopArgumentHack<'a, serenity::Attachment> for &PhantomData<serenity::Attachment> {
+impl<'a> PopArgument<'a> for serenity::Attachment {
     async fn pop_from(
-        self,
         args: &'a str,
         attachment_index: usize,
         ctx: &serenity::Context,
         msg: &serenity::Message,
-    ) -> Result<
-        (&'a str, usize, serenity::Attachment),
-        (Box<dyn std::error::Error + Send + Sync>, Option<String>),
-    > {
+    ) -> PopArgumentResult<'a, Self> {
         let attachment = msg
             .attachments
             .get(attachment_index)
@@ -136,6 +69,81 @@ impl<'a> PopArgumentHack<'a, serenity::Attachment> for &PhantomData<serenity::At
     }
 }
 
+#[async_trait::async_trait]
+impl<'a> PopArgument<'a> for String {
+    async fn pop_from(
+        args: &'a str,
+        attachment_index: usize,
+        ctx: &serenity::Context,
+        msg: &serenity::Message,
+    ) -> PopArgumentResult<'a, Self> {
+        match pop_string(args) {
+            Ok((args, string)) => Ok((args, attachment_index, string)),
+            Err(err) => Err((err.into(), Some(args.into()))),
+        }
+    }
+}
+
+async fn pop_from_argumentconvert<'a, T>(
+    args: &'a str,
+    attachment_index: usize,
+    ctx: &serenity::Context,
+    msg: &serenity::Message,
+) -> PopArgumentResult<'a, T>
+where
+    T: serenity::ArgumentConvert + Send,
+    T::Err: std::error::Error + Send + Sync + 'static,
+{
+    let (args, string) = pop_string(args).map_err(|_| (TooFewArguments::default().into(), None))?;
+    let object = T::convert(ctx, msg.guild_id, Some(msg.channel_id), &string)
+        .await
+        .map_err(|e| (e.into(), Some(string)))?;
+
+    Ok((args.trim_start(), attachment_index, object))
+}
+
+macro_rules! argumentconvert_pop_argument {
+    ( $(
+        $( #[cfg(feature = $feature:literal)] )?
+        $type:ty,
+    )* ) => {
+        $(
+            $( #[cfg(feature = $feature)] )?
+            #[async_trait::async_trait]
+            impl<'a> PopArgument<'a> for $type {
+                async fn pop_from(
+                    args: &'a str,
+                    attachment_index: usize,
+                    ctx: &serenity::Context,
+                    msg: &serenity::Message,
+                ) -> PopArgumentResult<'a, Self> {
+                    pop_from_argumentconvert(args, attachment_index, ctx, msg).await
+                }
+            }
+        )*
+    }
+}
+
+argumentconvert_pop_argument! {
+    // Via blanket impl of `ArgumentConvert` for `T: FromStr`
+    f32, f64,
+    u8, u16, u32, u64,
+    i8, i16, i32, i64,
+    serenity::Mention,
+
+    // Via explicit `ArgumentConvert` impls
+    serenity::User, serenity::Member,
+    serenity::Message,
+    serenity::Channel, serenity::GuildChannel,
+    serenity::EmojiId, serenity::Emoji,
+    serenity::Role,
+
+    #[cfg(feature = "cache")]
+    serenity::GuildId,
+    #[cfg(feature = "cache")]
+    serenity::Guild,
+}
+
 /// Macro to allow for using mentions in snowflake types
 macro_rules! snowflake_pop_argument {
     ($type:ty, $parse_fn:ident, $error_type:ident) => {
@@ -158,17 +166,13 @@ macro_rules! snowflake_pop_argument {
         }
 
         #[async_trait::async_trait]
-        impl<'a> PopArgumentHack<'a, $type> for &PhantomData<$type> {
+        impl<'a> PopArgument<'a> for $type {
             async fn pop_from(
-                self,
                 args: &'a str,
                 attachment_index: usize,
                 ctx: &serenity::Context,
                 msg: &serenity::Message,
-            ) -> Result<
-                (&'a str, usize, $type),
-                (Box<dyn std::error::Error + Send + Sync>, Option<String>),
-            > {
+            ) -> PopArgumentResult<'a, Self> {
                 let (args, string) =
                     pop_string(args).map_err(|_| (TooFewArguments::default().into(), None))?;