Compiling checkpoint

crates/gpui/playground_macros/src/style_methods.rs

@@ -0,0 +1,95 @@
+use proc_macro::TokenStream;
+use quote::{quote, ToTokens};
+use syn::{parse_macro_input, Expr, Ident, Token};
+
+struct Args {
+    method_name: Ident,
+    method_suffix: Option<Ident>,
+    field_name: Ident,
+    value: Expr,
+}
+
+impl syn::parse::Parse for Args {
+    fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> {
+        let method_name = input.parse()?;
+        let method_suffix = if input.peek(Token![::]) {
+            input.parse::<Token![::]>()?;
+            Some(input.parse()?)
+        } else {
+            None
+        };
+        input.parse::<Token![,]>()?;
+        let field_name = input.parse()?;
+        input.parse::<Token![,]>()?;
+        let value = input.parse()?;
+
+        Ok(Self {
+            method_name,
+            method_suffix,
+            field_name,
+            value,
+        })
+    }
+}
+
+fn fixed_lengths() -> Vec<(&'static str, proc_macro2::TokenStream)> {
+    vec![
+        ("0", quote! { DefinedLength::Pixels(0.) }),
+        ("px", quote! { DefinedLength::Pixels(1.) }),
+        ("0_5", quote! { DefinedLength::Rems(0.125) }),
+        // ...
+    ]
+}
+
+pub fn style_methods(input: TokenStream) -> TokenStream {
+    let Args {
+        method_name,
+        method_suffix,
+        field_name,
+        value,
+    } = parse_macro_input!(input as Args);
+
+    let hover_method_name = format!("hover_{}", method_name);
+    let hover_method_ident = syn::Ident::new(&hover_method_name, method_name.span());
+
+    let mut result = quote! {
+        fn #method_name(mut self) -> Self
+        where
+            Self: Sized,
+        {
+            self.metadata().style.#field_name = #value;
+            self
+        }
+
+        fn #hover_method_ident(mut self) -> Self
+        where
+            Self: Sized,
+        {
+            self.metadata().hover_style.#field_name = Some(#value);
+            self
+        }
+    };
+
+    if let Some(suffix_ident) = method_suffix {
+        if suffix_ident == "_" {
+            let fixed_lengths = fixed_lengths();
+
+            for (suffix, value) in fixed_lengths {
+                let method_ident =
+                    syn::Ident::new(&format!("{}_{}", method_name, suffix), method_name.span());
+                let method = quote! {
+                    fn #method_ident(mut self) -> Self
+                    where
+                        Self: Sized,
+                    {
+                        self.metadata().style.#field_name = #value;
+                        self
+                    }
+                };
+                result.extend(method);
+            }
+        }
+    }
+
+    result.into()
+}