Add ALL, from_str and math_op to Identifier

Introduce new API to iterate the function list and associate items with
their `MathOp`.

library/compiler-builtins/libm/crates/libm-macros/src/enums.rs

@@ -31,6 +31,7 @@ pub fn function_enum(
 
     let enum_name = &item.ident;
     let mut as_str_arms = Vec::new();
+    let mut from_str_arms = Vec::new();
     let mut base_arms = Vec::new();
 
     for func in ALL_OPERATIONS.iter() {
@@ -40,6 +41,7 @@ pub fn function_enum(
 
         // Match arm for `fn as_str(self)` matcher
         as_str_arms.push(quote! { Self::#ident => #fn_name });
+        from_str_arms.push(quote! { #fn_name => Self::#ident });
 
         // Match arm for `fn base_name(self)` matcher
         base_arms.push(quote! { Self::#ident => #base_enum::#bname_ident });
@@ -50,11 +52,18 @@ pub fn function_enum(
         item.variants.push(variant);
     }
 
+    let variants = item.variants.iter();
+
     let res = quote! {
         // Instantiate the enum
         #item
 
         impl #enum_name {
+            /// All variants of this enum.
+            pub const ALL: &[Self] = &[
+                #( Self::#variants, )*
+            ];
+
             /// The stringified version of this function name.
             pub const fn as_str(self) -> &'static str {
                 match self {
@@ -62,12 +71,26 @@ pub fn function_enum(
                 }
             }
 
+            /// If `s` is the name of a function, return it.
+            pub fn from_str(s: &str) -> Option<Self> {
+                let ret = match s {
+                    #( #from_str_arms , )*
+                    _ => return None,
+                };
+                Some(ret)
+            }
+
             /// The base name enum for this function.
             pub const fn base_name(self) -> #base_enum {
                 match self {
                     #( #base_arms, )*
                 }
             }
+
+            /// Return information about this operation.
+            pub fn math_op(self) -> &'static crate::op::MathOpInfo {
+                crate::op::ALL_OPERATIONS.iter().find(|op| op.name == self.as_str()).unwrap()
+            }
         }
     };
 

library/compiler-builtins/libm/crates/libm-macros/tests/enum.rs

@@ -1,6 +1,6 @@
 #[libm_macros::function_enum(BaseName)]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
-pub enum Function {}
+pub enum Identifier {}
 
 #[libm_macros::base_name_enum]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
@@ -8,12 +8,31 @@ pub enum BaseName {}
 
 #[test]
 fn as_str() {
-    assert_eq!(Function::Sin.as_str(), "sin");
-    assert_eq!(Function::Sinf.as_str(), "sinf");
+    assert_eq!(Identifier::Sin.as_str(), "sin");
+    assert_eq!(Identifier::Sinf.as_str(), "sinf");
+}
+
+#[test]
+fn from_str() {
+    assert_eq!(Identifier::from_str("sin").unwrap(), Identifier::Sin);
+    assert_eq!(Identifier::from_str("sinf").unwrap(), Identifier::Sinf);
 }
 
 #[test]
 fn basename() {
-    assert_eq!(Function::Sin.base_name(), BaseName::Sin);
-    assert_eq!(Function::Sinf.base_name(), BaseName::Sin);
+    assert_eq!(Identifier::Sin.base_name(), BaseName::Sin);
+    assert_eq!(Identifier::Sinf.base_name(), BaseName::Sin);
 }
+
+#[test]
+fn math_op() {
+    assert_eq!(Identifier::Sin.math_op().float_ty, FloatTy::F64);
+    assert_eq!(Identifier::Sinf.math_op().float_ty, FloatTy::F32);
+}
+
+// Replicate the structure that we have in `libm-test`
+mod op {
+    include!("../../libm-macros/src/shared.rs");
+}
+
+use op::FloatTy;