Improve prop docs (#1565)

* Do the stuff

* More sanitizing + fix warnings and format

packages/core-macro/src/utils.rs

@@ -0,0 +1,129 @@
+use quote::ToTokens;
+use syn::parse::{Parse, ParseStream};
+use syn::spanned::Spanned;
+use syn::{parse_quote, Expr, Lit, Meta, Token, Type};
+
+const FORMATTED_TYPE_START: &str = "static TY_AFTER_HERE:";
+const FORMATTED_TYPE_END: &str = "= todo!();";
+
+/// Attempts to convert the given literal to a string.
+/// Converts ints and floats to their base 10 counterparts.
+///
+/// Returns `None` if the literal is [`Lit::Verbatim`] or if the literal is [`Lit::ByteStr`]
+/// and the byte string could not be converted to UTF-8.
+pub fn lit_to_string(lit: Lit) -> Option<String> {
+    match lit {
+        Lit::Str(l) => Some(l.value()),
+        Lit::ByteStr(l) => String::from_utf8(l.value()).ok(),
+        Lit::Byte(l) => Some(String::from(l.value() as char)),
+        Lit::Char(l) => Some(l.value().to_string()),
+        Lit::Int(l) => Some(l.base10_digits().to_string()),
+        Lit::Float(l) => Some(l.base10_digits().to_string()),
+        Lit::Bool(l) => Some(l.value().to_string()),
+        Lit::Verbatim(_) => None,
+        _ => None,
+    }
+}
+
+pub fn format_type_string(ty: &Type) -> String {
+    let ty_unformatted = ty.into_token_stream().to_string();
+    let ty_unformatted = ty_unformatted.trim();
+
+    // This should always be valid syntax.
+    // Not Rust code, but syntax, which is the only thing that `syn` cares about.
+    let Ok(file_unformatted) = syn::parse_file(&format!(
+        "{FORMATTED_TYPE_START}{ty_unformatted}{FORMATTED_TYPE_END}"
+    )) else {
+        return ty_unformatted.to_string();
+    };
+
+    let file_formatted = prettyplease::unparse(&file_unformatted);
+
+    let file_trimmed = file_formatted.trim();
+    let start_removed = file_trimmed.trim_start_matches(FORMATTED_TYPE_START);
+    let end_removed = start_removed.trim_end_matches(FORMATTED_TYPE_END);
+    let ty_formatted = end_removed.trim();
+
+    ty_formatted.to_string()
+}
+
+/// Represents the `#[deprecated]` attribute.
+///
+/// You can use the [`DeprecatedAttribute::from_meta`] function to try to parse an attribute to this struct.
+#[derive(Default)]
+pub struct DeprecatedAttribute {
+    pub since: Option<String>,
+    pub note: Option<String>,
+}
+
+impl DeprecatedAttribute {
+    /// Returns `None` if the given attribute was not a valid form of the `#[deprecated]` attribute.
+    pub fn from_meta(meta: &Meta) -> syn::Result<Self> {
+        if meta.path() != &parse_quote!(deprecated) {
+            return Err(syn::Error::new(
+                meta.span(),
+                "attribute path is not `deprecated`",
+            ));
+        }
+
+        match &meta {
+            Meta::Path(_) => Ok(Self::default()),
+            Meta::NameValue(name_value) => {
+                let Expr::Lit(expr_lit) = &name_value.value else {
+                    return Err(syn::Error::new(
+                        name_value.span(),
+                        "literal in `deprecated` value must be a string",
+                    ));
+                };
+
+                Ok(Self {
+                    since: None,
+                    note: lit_to_string(expr_lit.lit.clone()).map(|s| s.trim().to_string()),
+                })
+            }
+            Meta::List(list) => {
+                let parsed = list.parse_args::<DeprecatedAttributeArgsParser>()?;
+
+                Ok(Self {
+                    since: parsed.since.map(|s| s.trim().to_string()),
+                    note: parsed.note.map(|s| s.trim().to_string()),
+                })
+            }
+        }
+    }
+}
+
+mod kw {
+    use syn::custom_keyword;
+    custom_keyword!(since);
+    custom_keyword!(note);
+}
+
+struct DeprecatedAttributeArgsParser {
+    since: Option<String>,
+    note: Option<String>,
+}
+
+impl Parse for DeprecatedAttributeArgsParser {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        let mut since: Option<String> = None;
+        let mut note: Option<String> = None;
+
+        if input.peek(kw::since) {
+            input.parse::<kw::since>()?;
+            input.parse::<Token![=]>()?;
+
+            since = lit_to_string(input.parse()?);
+        }
+
+        if input.peek(Token![,]) && input.peek2(kw::note) {
+            input.parse::<Token![,]>()?;
+            input.parse::<kw::note>()?;
+            input.parse::<Token![=]>()?;
+
+            note = lit_to_string(input.parse()?);
+        }
+
+        Ok(Self { since, note })
+    }
+}