tamer: nir::NirSymbolTy (Display): Add impl

Add initial descriptions and consolodate some of the types.  There'll be
more to come; this is just to get `Display` derives working for types
that'll be using it.  I'd like to see where this description manifests
itself before I decide how user-friendly I'd like it to be.

DEV-13156

tamer/src/nir.rs

@@ -173,7 +173,6 @@ impl Display for SugaredNir {
 pub enum NirSymbolTy {
     AnyIdent,
     BooleanLiteral,
-    CalcIdent,
     ClassIdent,
     ClassIdentList,
     ConstIdent,
@@ -190,19 +189,64 @@ pub enum NirSymbolTy {
     ParamName,
     ParamType,
     PkgPath,
-    PkgTitle,
     ShortDimNumLiteral,
     StringLiteral,
     SymbolTableKey,
     TexMathLiteral,
     Title,
     TplMetaIdent,
-    TplName,
+    TplIdent,
     TplParamIdent,
     TypeIdent,
     ValueIdent,
 }
 
+impl Display for NirSymbolTy {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        use NirSymbolTy::*;
+
+        match self {
+            AnyIdent => write!(f, "any identifier"),
+            BooleanLiteral => write!(
+                f,
+                "boolean literal {fmt_true} or {fmt_false}",
+                fmt_true = TtQuote::wrap("true"),
+                fmt_false = TtQuote::wrap("false"),
+            ),
+            ClassIdent => write!(f, "classification identifier"),
+            ClassIdentList => {
+                write!(f, "space-delimited list of classification identifiers")
+            }
+            ConstIdent => write!(f, "constant identifier"),
+            DescLiteral => write!(f, "description literal"),
+            Dim => write!(f, "dimension declaration"),
+            DynNodeLiteral => write!(f, "dynamic node literal"),
+            FuncIdent => write!(f, "function identifier"),
+            IdentDtype => write!(f, "identifier primitive datatype"),
+            IdentType => write!(f, "identifier type"),
+            MapTransformLiteral => write!(f, "map transformation literal"),
+            NumLiteral => write!(f, "numeric literal"),
+            ParamDefault => write!(f, "param default"),
+            ParamIdent => write!(f, "param identifier"),
+            ParamName => write!(f, "param name"),
+            ParamType => write!(f, "param type"),
+            PkgPath => write!(f, "package path"),
+            ShortDimNumLiteral => {
+                write!(f, "short-hand dimensionalized numeric literal")
+            }
+            StringLiteral => write!(f, "string literal"),
+            SymbolTableKey => write!(f, "symbol table key name"),
+            TexMathLiteral => write!(f, "TeX math literal"),
+            Title => write!(f, "title"),
+            TplMetaIdent => write!(f, "template metadata identifier"),
+            TplIdent => write!(f, "template name"),
+            TplParamIdent => write!(f, "template param identifier"),
+            TypeIdent => write!(f, "type identifier"),
+            ValueIdent => write!(f, "value identifier"),
+        }
+    }
+}
+
 /// A ([`SymbolId`], [`Span`]) pair in an attribute value context that may
 ///   require desugaring and interpretation within the context of a template
 ///   application.

tamer/src/nir/parse.rs

@@ -230,7 +230,7 @@ ele_parse! {
             _xmlns_lv: (QN_XMLNS_LV?) => Option<Literal<URI_LV_RATER>>,
 
             _id: (QN_ID?) => Option<N<{PkgPath}>>,
-            _title: (QN_TITLE?) => Option<N<{PkgTitle}>>,
+            _title: (QN_TITLE?) => Option<N<{Title}>>,
             _desc: (QN_DESC?) => Option<N<{DescLiteral}>>,
             // TODO: When can we get rid of this?
             _core: (QN_CORE?) => Option<N<{BooleanLiteral}>>,
@@ -403,7 +403,7 @@ ele_parse! {
         @ {
             _class: (QN_CLASS?) => Option<N<{ClassIdent}>>,
             _no: (QN_NO?) => Option<N<{ClassIdentList}>>,
-            _yields: (QN_YIELDS) => N<{CalcIdent}>,
+            _yields: (QN_YIELDS) => N<{ValueIdent}>,
             _desc: (QN_DESC?) => Option<N<{DescLiteral}>>,
             _sym: (QN_SYM?) => Option<N<{TexMathLiteral}>>,
 
@@ -656,8 +656,8 @@ ele_parse! {
     SumExpr := QN_C_SUM {
         @ {
             _of: (QN_OF?) => Option<N<{ValueIdent}>>,
-            _generates: (QN_GENERATES?) => Option<N<{CalcIdent}>>,
-            _index: (QN_INDEX?) => Option<N<{CalcIdent}>>,
+            _generates: (QN_GENERATES?) => Option<N<{ValueIdent}>>,
+            _index: (QN_INDEX?) => Option<N<{ValueIdent}>>,
             _desc: (QN_DESC?) => Option<N<{DescLiteral}>>,
             _label: (QN_LABEL?) => Option<N<{DescLiteral}>>,
             _sym: (QN_SYM?) => Option<N<{TexMathLiteral}>>,
@@ -677,8 +677,8 @@ ele_parse! {
     ProductExpr := QN_C_PRODUCT {
         @ {
             _of: (QN_OF?) => Option<N<{ValueIdent}>>,
-            _generates: (QN_GENERATES?) => Option<N<{CalcIdent}>>,
-            _index: (QN_INDEX?) => Option<N<{CalcIdent}>>,
+            _generates: (QN_GENERATES?) => Option<N<{ValueIdent}>>,
+            _index: (QN_INDEX?) => Option<N<{ValueIdent}>>,
             _desc: (QN_DESC?) => Option<N<{DescLiteral}>>,
             _label: (QN_LABEL?) => Option<N<{DescLiteral}>>,
             _dot: (QN_DOT?) => Option<N<{BooleanLiteral}>>,
@@ -1376,7 +1376,7 @@ ele_parse! {
     /// Templates are applied using [`ApplyTemplate`] or [`TplApplyShort`].
     TemplateStmt := QN_TEMPLATE {
         @ {
-            _name: (QN_NAME) => N<{TplName}>,
+            _name: (QN_NAME) => N<{TplIdent}>,
             _desc: (QN_DESC) => N<{DescLiteral}>,
         } => SugaredNir::Todo,