dioxus-mirror/packages/rsx/src/attribute.rs

//! Parser for the attribute shared both by elements and components
//!
//! ```rust, ignore
//! rsx! {
//!     div {
//!         class: "my-class",
//!         onclick: move |_| println!("clicked")
//!     }
//!
//!     Component {
//!         class: "my-class",
//!         onclick: move |_| println!("clicked")
//!     }
//! }
//! ```

use super::literal::HotLiteral;
use crate::{innerlude::*, partial_closure::PartialClosure};

use proc_macro2::TokenStream as TokenStream2;
use quote::{quote, quote_spanned, ToTokens, TokenStreamExt};
use std::fmt::Display;
use syn::{
    ext::IdentExt,
    parse::{Parse, ParseStream},
    parse_quote,
    spanned::Spanned,
    Block, Expr, ExprClosure, ExprIf, Ident, Lit, LitBool, LitFloat, LitInt, LitStr, Token,
};

/// A property value in the from of a `name: value` pair with an optional comma.
/// Note that the colon and value are optional in the case of shorthand attributes. We keep them around
/// to support "lossless" parsing in case that ever might be useful.
#[derive(PartialEq, Eq, Clone, Debug, Hash)]
pub struct Attribute {
    /// The name of the attribute (ident or custom)
    ///
    /// IE `class` or `onclick`
    pub name: AttributeName,

    /// The colon that separates the name and value - keep this for lossless parsing
    pub colon: Option<Token![:]>,

    /// The value of the attribute
    ///
    /// IE `class="my-class"` or `onclick: move |_| println!("clicked")`
    pub value: AttributeValue,

    /// The comma that separates this attribute from the next one
    /// Used for more accurate completions
    pub comma: Option<Token![,]>,

    /// The dynamic index of this attribute - used by the template system
    pub dyn_idx: DynIdx,

    /// The element name of this attribute if it is bound to an element.
    /// When parsed for components or freestanding, this will be None
    pub el_name: Option<ElementName>,
}

impl Parse for Attribute {
    fn parse(content: ParseStream) -> syn::Result<Self> {
        // if there's an ident not followed by a colon, it's a shorthand attribute
        if content.peek(Ident::peek_any) && !content.peek2(Token![:]) {
            let ident = parse_raw_ident(content)?;
            let comma = content.parse().ok();

            return Ok(Attribute {
                name: AttributeName::BuiltIn(ident.clone()),
                colon: None,
                value: AttributeValue::Shorthand(ident),
                comma,
                dyn_idx: DynIdx::default(),
                el_name: None,
            });
        }

        // Parse the name as either a known or custom attribute
        let name = match content.peek(LitStr) {
            true => AttributeName::Custom(content.parse::<LitStr>()?),
            false => AttributeName::BuiltIn(parse_raw_ident(content)?),
        };

        // Ensure there's a colon
        let colon = Some(content.parse::<Token![:]>()?);

        // todo: make this cleaner please
        // if statements in attributes get automatic closing in some cases
        // we shouldn't be handling it any differently.
        let value = AttributeValue::parse(content)?;

        let comma = content.parse::<Token![,]>().ok();

        let attr = Attribute {
            name,
            value,
            colon,
            comma,
            dyn_idx: DynIdx::default(),
            el_name: None,
        };

        Ok(attr)
    }
}

impl Attribute {
    /// Create a new attribute from a name and value
    pub fn from_raw(name: AttributeName, value: AttributeValue) -> Self {
        Self {
            name,
            colon: Default::default(),
            value,
            comma: Default::default(),
            dyn_idx: Default::default(),
            el_name: None,
        }
    }

    /// Set the dynamic index of this attribute
    pub fn set_dyn_idx(&self, idx: usize) {
        self.dyn_idx.set(idx);
    }

    /// Get the dynamic index of this attribute
    pub fn get_dyn_idx(&self) -> usize {
        self.dyn_idx.get()
    }

    pub fn span(&self) -> proc_macro2::Span {
        self.name.span()
    }

    pub fn as_lit(&self) -> Option<&HotLiteral> {
        match &self.value {
            AttributeValue::AttrLiteral(lit) => Some(lit),
            _ => None,
        }
    }

    /// Run this closure against the attribute if it's hotreloadable
    pub fn with_literal(&self, f: impl FnOnce(&HotLiteral)) {
        if let AttributeValue::AttrLiteral(ifmt) = &self.value {
            f(ifmt);
        }
    }

    pub fn ifmt(&self) -> Option<&IfmtInput> {
        match &self.value {
            AttributeValue::AttrLiteral(HotLiteral::Fmted(input)) => Some(input),
            _ => None,
        }
    }

    pub fn as_static_str_literal(&self) -> Option<(&AttributeName, &IfmtInput)> {
        match &self.value {
            AttributeValue::AttrLiteral(lit) => match &lit {
                HotLiteral::Fmted(input) if input.is_static() => Some((&self.name, input)),
                _ => None,
            },
            _ => None,
        }
    }

    pub fn is_static_str_literal(&self) -> bool {
        self.as_static_str_literal().is_some()
    }

    pub fn rendered_as_dynamic_attr(&self) -> TokenStream2 {
        // Shortcut out with spreads
        if let AttributeName::Spread(_) = self.name {
            let AttributeValue::AttrExpr(expr) = &self.value else {
                unreachable!("Spread attributes should always be expressions")
            };
            return quote! { {#expr}.into_boxed_slice() };
        }

        let el_name = self
            .el_name
            .as_ref()
            .expect("el_name rendered as a dynamic attribute should always have an el_name set");

        let ns = |name: &AttributeName| match (el_name, name) {
            (ElementName::Ident(i), AttributeName::BuiltIn(_)) => {
                quote! { dioxus_elements::#i::#name.1 }
            }
            _ => quote! { None },
        };

        let volatile = |name: &AttributeName| match (el_name, name) {
            (ElementName::Ident(i), AttributeName::BuiltIn(_)) => {
                quote! { dioxus_elements::#i::#name.2 }
            }
            _ => quote! { false },
        };

        let attribute = |name: &AttributeName| match name {
            AttributeName::BuiltIn(name) => match el_name {
                ElementName::Ident(_) => quote! { dioxus_elements::#el_name::#name.0 },
                ElementName::Custom(_) => {
                    let as_string = name.to_string();
                    quote!(#as_string)
                }
            },
            AttributeName::Custom(s) => quote! { #s },
            AttributeName::Spread(_) => unreachable!("Spread attributes are handled elsewhere"),
        };

        let attribute = {
            let value = &self.value;
            let name = &self.name;
            let is_not_event = !self.name.is_likely_event();

            match &self.value {
                AttributeValue::AttrLiteral(_)
                | AttributeValue::AttrExpr(_)
                | AttributeValue::Shorthand(_)
                | AttributeValue::IfExpr { .. }
                    if is_not_event =>
                {
                    let name = &self.name;
                    let ns = ns(name);
                    let volatile = volatile(name);
                    let attribute = attribute(name);
                    let value = quote! { #value };

                    quote! {
                        dioxus_core::Attribute::new(
                            #attribute,
                            #value,
                            #ns,
                            #volatile
                        )
                    }
                }
                AttributeValue::EventTokens(tokens) => match &self.name {
                    AttributeName::BuiltIn(name) => {
                        let event_tokens_is_closure =
                            syn::parse2::<ExprClosure>(tokens.to_token_stream()).is_ok();
                        let function_name =
                            quote_spanned! { tokens.span() => dioxus_elements::events::#name };
                        let function = if event_tokens_is_closure {
                            // If we see an explicit closure, we can call the `call_with_explicit_closure` version of the event for better type inference
                            quote_spanned! { tokens.span() => #function_name::call_with_explicit_closure }
                        } else {
                            function_name
                        };
                        quote_spanned! { tokens.span() =>
                            #function(#tokens)
                        }
                    }
                    AttributeName::Custom(_) => unreachable!("Handled elsewhere in the macro"),
                    AttributeName::Spread(_) => unreachable!("Handled elsewhere in the macro"),
                },
                _ => {
                    quote_spanned! { value.span() => dioxus_elements::events::#name(#value) }
                }
            }
        };

        let completion_hints = self.completion_hints();
        quote! {
            Box::new([
                {
                    #completion_hints
                    #attribute
                }
            ])
        }
        .to_token_stream()
    }

    pub fn can_be_shorthand(&self) -> bool {
        // If it's a shorthand...
        if matches!(self.value, AttributeValue::Shorthand(_)) {
            return true;
        }

        // Or if it is a builtin attribute with a single ident value
        if let (AttributeName::BuiltIn(name), AttributeValue::AttrExpr(expr)) =
            (&self.name, &self.value)
        {
            if let Ok(Expr::Path(path)) = expr.as_expr() {
                if path.path.get_ident() == Some(name) {
                    return true;
                }
            }
        }

        false
    }

    /// If this is the last attribute of an element and it doesn't have a tailing comma,
    /// we add hints so that rust analyzer completes it either as an attribute or element
    fn completion_hints(&self) -> TokenStream2 {
        let Attribute {
            name,
            value,
            comma,
            el_name,
            ..
        } = self;

        // If there is a trailing comma, rust analyzer does a good job of completing the attribute by itself
        if comma.is_some() {
            return quote! {};
        }

        // Only add hints if the attribute is:
        // - a built in attribute (not a literal)
        // - an build in element (not a custom element)
        // - a shorthand attribute
        let (
            Some(ElementName::Ident(el)),
            AttributeName::BuiltIn(name),
            AttributeValue::Shorthand(_),
        ) = (&el_name, &name, &value)
        else {
            return quote! {};
        };
        // If the attribute is a shorthand attribute, but it is an event handler, rust analyzer already does a good job of completing the attribute by itself
        if name.to_string().starts_with("on") {
            return quote! {};
        }

        quote! {
            {
                #[allow(dead_code)]
                #[doc(hidden)]
                mod __completions {
                    // Autocomplete as an attribute
                    pub use super::dioxus_elements::#el::*;
                    // Autocomplete as an element
                    pub use super::dioxus_elements::elements::completions::CompleteWithBraces::*;
                    fn ignore() {
                        #name;
                    }
                }
            }
        }
    }
}

#[derive(PartialEq, Eq, Clone, Debug, Hash)]
pub enum AttributeName {
    Spread(Token![..]),

    /// an attribute in the form of `name: value`
    BuiltIn(Ident),

    /// an attribute in the form of `"name": value` - notice that the name is a string literal
    /// this is to allow custom attributes in the case of missing built-in attributes
    ///
    /// we might want to change this one day to be ticked or something and simply a boolean
    Custom(LitStr),
}

impl AttributeName {
    pub fn is_likely_event(&self) -> bool {
        matches!(self, Self::BuiltIn(ident) if ident.to_string().starts_with("on"))
    }

    pub fn is_likely_key(&self) -> bool {
        matches!(self, Self::BuiltIn(ident) if ident == "key")
    }

    pub fn span(&self) -> proc_macro2::Span {
        match self {
            Self::Custom(lit) => lit.span(),
            Self::BuiltIn(ident) => ident.span(),
            Self::Spread(dots) => dots.span(),
        }
    }
}

impl Display for AttributeName {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Custom(lit) => write!(f, "{}", lit.value()),
            Self::BuiltIn(ident) => write!(f, "{}", ident),
            Self::Spread(_) => write!(f, ".."),
        }
    }
}

impl ToTokens for AttributeName {
    fn to_tokens(&self, tokens: &mut TokenStream2) {
        match self {
            Self::Custom(lit) => lit.to_tokens(tokens),
            Self::BuiltIn(ident) => ident.to_tokens(tokens),
            Self::Spread(dots) => dots.to_tokens(tokens),
        }
    }
}

// ..spread attribute
#[derive(PartialEq, Eq, Clone, Debug, Hash)]
pub struct Spread {
    pub dots: Token![..],
    pub expr: Expr,
    pub dyn_idx: DynIdx,
    pub comma: Option<Token![,]>,
}

impl Spread {
    pub fn span(&self) -> proc_macro2::Span {
        self.dots.span()
    }
}

#[derive(PartialEq, Eq, Clone, Debug, Hash)]
pub enum AttributeValue {
    /// Just a regular shorthand attribute - an ident. Makes our parsing a bit more opaque.
    /// attribute,
    Shorthand(Ident),

    /// Any attribute that's a literal. These get hotreloading super powers
    ///
    /// attribute: "value"
    /// attribute: bool,
    /// attribute: 1,
    AttrLiteral(HotLiteral),

    /// A series of tokens that represent an event handler
    ///
    /// We use a special type here so we can get autocomplete in the closure using partial expansion.
    /// We also do some extra wrapping for improved type hinting since rust sometimes has trouble with
    /// generics and closures.
    EventTokens(PartialClosure),

    /// Conditional expression
    ///
    /// attribute: if bool { "value" } else if bool { "other value" } else { "default value" }
    ///
    /// Currently these don't get hotreloading super powers, but they could, depending on how far
    /// we want to go with it
    IfExpr(IfAttributeValue),

    /// attribute: some_expr
    /// attribute: {some_expr} ?
    AttrExpr(PartialExpr),
}

impl Parse for AttributeValue {
    fn parse(content: ParseStream) -> syn::Result<Self> {
        // Attempt to parse the unterminated if statement
        if content.peek(Token![if]) {
            return Ok(Self::IfExpr(content.parse::<IfAttributeValue>()?));
        }

        // Use the move and/or bars as an indicator that we have an event handler
        if content.peek(Token![move]) || content.peek(Token![|]) {
            let value = content.parse()?;
            return Ok(AttributeValue::EventTokens(value));
        }

        if content.peek(LitStr)
            || content.peek(LitBool)
            || content.peek(LitFloat)
            || content.peek(LitInt)
        {
            let fork = content.fork();
            _ = fork.parse::<Lit>().unwrap();

            if content.peek2(Token![,]) || fork.is_empty() {
                let value = content.parse()?;
                return Ok(AttributeValue::AttrLiteral(value));
            }
        }

        let value = content.parse::<PartialExpr>()?;
        Ok(AttributeValue::AttrExpr(value))
    }
}

impl ToTokens for AttributeValue {
    fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
        match self {
            Self::Shorthand(ident) => ident.to_tokens(tokens),
            Self::AttrLiteral(ifmt) => ifmt.to_tokens(tokens),
            Self::IfExpr(if_expr) => if_expr.to_tokens(tokens),
            Self::AttrExpr(expr) => expr.to_tokens(tokens),
            Self::EventTokens(closure) => closure.to_tokens(tokens),
        }
    }
}

impl AttributeValue {
    pub fn span(&self) -> proc_macro2::Span {
        match self {
            Self::Shorthand(ident) => ident.span(),
            Self::AttrLiteral(ifmt) => ifmt.span(),
            Self::IfExpr(if_expr) => if_expr.span(),
            Self::AttrExpr(expr) => expr.span(),
            Self::EventTokens(closure) => closure.span(),
        }
    }
}

/// A if else chain attribute value
#[derive(PartialEq, Eq, Clone, Debug, Hash)]
pub struct IfAttributeValue {
    pub condition: Expr,
    pub then_value: Box<AttributeValue>,
    pub else_value: Option<Box<AttributeValue>>,
}

impl IfAttributeValue {
    /// Convert the if expression to an expression that returns a string. If the unterminated case is hit, it returns an empty string
    pub(crate) fn quote_as_string(&self, diagnostics: &mut Diagnostics) -> Expr {
        let mut expression = quote! {};
        let mut current_if_value = self;

        let mut non_string_diagnostic = |span: proc_macro2::Span| -> Expr {
            Element::add_merging_non_string_diagnostic(diagnostics, span);
            parse_quote! { ::std::string::String::new() }
        };

        loop {
            let AttributeValue::AttrLiteral(lit) = current_if_value.then_value.as_ref() else {
                return non_string_diagnostic(current_if_value.span());
            };

            let HotLiteral::Fmted(HotReloadFormattedSegment {
                formatted_input: new,
                ..
            }) = &lit
            else {
                return non_string_diagnostic(current_if_value.span());
            };

            let condition = &current_if_value.condition;
            expression.extend(quote! {
                if #condition {
                    #new.to_string()
                } else
            });
            match current_if_value.else_value.as_deref() {
                // If the else value is another if expression, then we need to continue the loop
                Some(AttributeValue::IfExpr(else_value)) => {
                    current_if_value = else_value;
                }
                // If the else value is a literal, then we need to append it to the expression and break
                Some(AttributeValue::AttrLiteral(lit)) => {
                    if let HotLiteral::Fmted(new) = &lit {
                        let fmted = &new.formatted_input;
                        expression.extend(quote! { { #fmted.to_string() } });
                        break;
                    } else {
                        return non_string_diagnostic(current_if_value.span());
                    }
                }
                // If it is the end of the if expression without an else, then we need to append the default value and break
                None => {
                    expression.extend(quote! { { ::std::string::String::new() } });
                    break;
                }
                _ => {
                    return non_string_diagnostic(current_if_value.else_value.span());
                }
            }
        }

        parse_quote! {
            {
                #expression
            }
        }
    }

    fn span(&self) -> proc_macro2::Span {
        self.then_value.span()
    }

    fn is_terminated(&self) -> bool {
        match &self.else_value {
            Some(attribute) => match attribute.as_ref() {
                AttributeValue::IfExpr(if_expr) => if_expr.is_terminated(),
                _ => true,
            },
            None => false,
        }
    }

    fn contains_expression(&self) -> bool {
        if let AttributeValue::AttrExpr(_) = &*self.then_value {
            return true;
        }
        match &self.else_value {
            Some(attribute) => match attribute.as_ref() {
                AttributeValue::IfExpr(if_expr) => if_expr.is_terminated(),
                AttributeValue::AttrExpr(_) => true,
                _ => false,
            },
            None => false,
        }
    }

    fn parse_attribute_value_from_block(block: &Block) -> syn::Result<Box<AttributeValue>> {
        let stmts = &block.stmts;

        if stmts.len() != 1 {
            return Err(syn::Error::new(
                block.span(),
                "Expected a single statement in the if block",
            ));
        }

        // either an ifmt or an expr in the block
        let stmt = &stmts[0];

        // Either it's a valid ifmt or an expression
        match stmt {
            syn::Stmt::Expr(exp, None) => {
                // Try parsing the statement as an IfmtInput by passing it through tokens
                let value: Result<HotLiteral, syn::Error> = syn::parse2(quote! { #exp });
                Ok(match value {
                    Ok(res) => Box::new(AttributeValue::AttrLiteral(res)),
                    Err(_) => Box::new(AttributeValue::AttrExpr(PartialExpr::from_expr(exp))),
                })
            }
            _ => Err(syn::Error::new(stmt.span(), "Expected an expression")),
        }
    }

    fn to_tokens_with_terminated(
        &self,
        tokens: &mut TokenStream2,
        terminated: bool,
        contains_expression: bool,
    ) {
        let IfAttributeValue {
            condition,
            then_value,
            else_value,
        } = self;

        // Quote an attribute value and convert the value to a string if it is formatted
        // We always quote formatted segments as strings inside if statements so they have a consistent type
        // This fixes https://github.com/DioxusLabs/dioxus/issues/2997
        fn quote_attribute_value_string(
            value: &AttributeValue,
            contains_expression: bool,
        ) -> TokenStream2 {
            if let AttributeValue::AttrLiteral(HotLiteral::Fmted(fmted)) = value {
                if let Some(str) = fmted.to_static().filter(|_| contains_expression) {
                    // If this is actually a static string, the user may be using a static string expression in another branch
                    // use into to convert the string to whatever the other branch is using
                    quote! {
                        {
                            #[allow(clippy::useless_conversion)]
                            #str.into()
                        }
                    }
                } else {
                    quote! { #value.to_string() }
                }
            } else {
                value.to_token_stream()
            }
        }

        let then_value = quote_attribute_value_string(then_value, terminated);

        let then_value = if terminated {
            quote! { #then_value }
        }
        // Otherwise we need to return an Option and a None if the else value is None
        else {
            quote! { Some(#then_value) }
        };

        let else_value = match else_value.as_deref() {
            Some(AttributeValue::IfExpr(else_value)) => {
                let mut tokens = TokenStream2::new();
                else_value.to_tokens_with_terminated(&mut tokens, terminated, contains_expression);
                tokens
            }
            Some(other) => {
                let other = quote_attribute_value_string(other, contains_expression);
                if terminated {
                    quote! { #other }
                } else {
                    quote! { Some(#other) }
                }
            }
            None => quote! { None },
        };

        tokens.append_all(quote! {
            {
                if #condition {
                    #then_value
                } else {
                    #else_value
                }
            }
        });
    }
}

impl Parse for IfAttributeValue {
    fn parse(input: ParseStream) -> syn::Result<Self> {
        let if_expr = input.parse::<ExprIf>()?;

        let stmts = &if_expr.then_branch.stmts;

        if stmts.len() != 1 {
            return Err(syn::Error::new(
                if_expr.then_branch.span(),
                "Expected a single statement in the if block",
            ));
        }

        // Parse the then branch into a single attribute value
        let then_value = Self::parse_attribute_value_from_block(&if_expr.then_branch)?;

        // If there's an else branch, parse it as a single attribute value or an if expression
        let else_value = match if_expr.else_branch.as_ref() {
            Some((_, else_branch)) => {
                // The else branch if either a block or another if expression
                let attribute_value = match else_branch.as_ref() {
                    // If it is a block, then the else is terminated
                    Expr::Block(block) => Self::parse_attribute_value_from_block(&block.block)?,
                    // Otherwise try to parse it as an if expression
                    _ => Box::new(syn::parse2(quote! { #else_branch })?),
                };
                Some(attribute_value)
            }
            None => None,
        };

        Ok(Self {
            condition: *if_expr.cond,
            then_value,
            else_value,
        })
    }
}

impl ToTokens for IfAttributeValue {
    fn to_tokens(&self, tokens: &mut TokenStream2) {
        // If the if expression is terminated, we can just return the then value
        let terminated = self.is_terminated();
        let contains_expression = self.contains_expression();
        self.to_tokens_with_terminated(tokens, terminated, contains_expression)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use quote::quote;
    use syn::parse2;

    #[test]
    fn parse_attrs() {
        let _parsed: Attribute = parse2(quote! { name: "value" }).unwrap();
        let _parsed: Attribute = parse2(quote! { name: value }).unwrap();
        let _parsed: Attribute = parse2(quote! { name: "value {fmt}" }).unwrap();
        let _parsed: Attribute = parse2(quote! { name: 123 }).unwrap();
        let _parsed: Attribute = parse2(quote! { name: false }).unwrap();
        let _parsed: Attribute = parse2(quote! { "custom": false }).unwrap();
        let _parsed: Attribute = parse2(quote! { prop: "blah".to_string() }).unwrap();

        // with commas
        let _parsed: Attribute = parse2(quote! { "custom": false, }).unwrap();
        let _parsed: Attribute = parse2(quote! { name: false, }).unwrap();

        // with if chains
        let parsed: Attribute = parse2(quote! { name: if true { "value" } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::IfExpr(_)));
        let parsed: Attribute =
            parse2(quote! { name: if true { "value" } else { "other" } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::IfExpr(_)));
        let parsed: Attribute =
            parse2(quote! { name: if true { "value" } else if false { "other" } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::IfExpr(_)));

        // with shorthand
        let _parsed: Attribute = parse2(quote! { name }).unwrap();
        let _parsed: Attribute = parse2(quote! { name, }).unwrap();

        // Events - make sure they get partial expansion
        let parsed: Attribute = parse2(quote! { onclick: |e| {} }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
        let parsed: Attribute = parse2(quote! { onclick: |e| { "value" } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
        let parsed: Attribute = parse2(quote! { onclick: |e| { value. } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
        let parsed: Attribute = parse2(quote! { onclick: move |e| { value. } }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
        let parsed: Attribute = parse2(quote! { onclick: move |e| value }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
        let parsed: Attribute = parse2(quote! { onclick: |e| value, }).unwrap();
        assert!(matches!(parsed.value, AttributeValue::EventTokens(_)));
    }

    #[test]
    fn merge_attrs() {
        let _a: Attribute = parse2(quote! { class: "value1" }).unwrap();
        let _b: Attribute = parse2(quote! { class: "value2" }).unwrap();

        let _b: Attribute = parse2(quote! { class: "value2 {something}" }).unwrap();
        let _b: Attribute = parse2(quote! { class: if value { "other thing" } }).unwrap();
        let _b: Attribute = parse2(quote! { class: if value { some_expr } }).unwrap();

        let _b: Attribute = parse2(quote! { class: if value { "some_expr" } }).unwrap();
        dbg!(_b);
    }

    #[test]
    fn static_literals() {
        let a: Attribute = parse2(quote! { class: "value1" }).unwrap();
        let b: Attribute = parse2(quote! { class: "value {some}" }).unwrap();

        assert!(a.is_static_str_literal());
        assert!(!b.is_static_str_literal());
    }

    #[test]
    fn partial_eqs() {
        // Basics
        let a: Attribute = parse2(quote! { class: "value1" }).unwrap();
        let b: Attribute = parse2(quote! { class: "value1" }).unwrap();
        assert_eq!(a, b);

        // Exprs
        let a: Attribute = parse2(quote! { class: var }).unwrap();
        let b: Attribute = parse2(quote! { class: var }).unwrap();
        assert_eq!(a, b);

        // Events
        let a: Attribute = parse2(quote! { onclick: |e| {} }).unwrap();
        let b: Attribute = parse2(quote! { onclick: |e| {} }).unwrap();
        let c: Attribute = parse2(quote! { onclick: move |e| {} }).unwrap();
        assert_eq!(a, b);
        assert_ne!(a, c);
    }

    /// Make sure reserved keywords are parsed as attributes
    /// HTML gets annoying sometimes so we just accept them
    #[test]
    fn reserved_keywords() {
        let _a: Attribute = parse2(quote! { for: "class" }).unwrap();
        let _b: Attribute = parse2(quote! { type: "class" }).unwrap();
    }
}