tamer: xir::st: Static namespace prefixes (c and t)

In particular, `t:*` will be recognized by NIR for short-hand template
application.  These will be utilized in an upcoming commit.

DEV-7145

tamer/src/lib.rs

@@ -73,6 +73,8 @@
 #![feature(adt_const_params)]
 // We build docs for private items.
 #![allow(rustdoc::private_intra_doc_links)]
+// For sym::prefill recursive macro `static_symbols!`.
+#![recursion_limit = "256"]
 
 pub mod global;
 

tamer/src/sym/prefill.rs

@@ -498,6 +498,7 @@ pub mod st {
         N9: dec "9",
 
         L_BOOLEAN: cid "boolean",
+        L_C: cid "c",
         L_CGEN: cid "cgen",
         L_CLASS: cid "class",
         L_CLASSIFY: cid "classify",
@@ -549,6 +550,7 @@ pub mod st {
         L_SYM_DEP: cid "sym-dep",
         L_SYM_DEPS: cid "sym-deps",
         L_SYM_REF: cid "sym-ref",
+        L_T: cid "t",
         L_TITLE: cid "title",
         L_TPL: cid "tpl",
         L_TRUE: cid "true",

tamer/src/xir.rs

@@ -160,6 +160,15 @@ impl TryFrom<&str> for NCName {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct Prefix(NCName);
 
+impl Prefix {
+    /// Construct a constant [`Prefix`] from a static C-style symbol.
+    pub const fn st_cid<T: QNameCompatibleStaticSymbolId>(
+        prefix_sym: &T,
+    ) -> Self {
+        Self(NCName(st_as_sym(prefix_sym)))
+    }
+}
+
 /// Local name portion of a [`QName`].
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct LocalPart(NCName);

tamer/src/xir/st.rs

@@ -21,10 +21,25 @@
 //!
 //! This is analogous to [`crate::sym::st`].
 
+use crate::sym::st::*;
+
+pub mod prefix {
+    //! Static [`Prefix`]es.
+
+    use super::super::Prefix;
+    use super::*;
+
+    /// Namespace prefix [`L_C`] used for calculation expressions.
+    pub const NS_C: Prefix = Prefix::st_cid(&L_C);
+
+    /// Namespace prefix [`L_T`] used for short-hand template application.
+    pub const NS_T: Prefix = Prefix::st_cid(&L_T);
+}
+
 pub mod qname {
     //! Static [`QName`]s.
 
-    use crate::sym::st::*;
+    use super::*;
     use crate::sym::{
         CIdentStaticSymbolId, StaticSymbolId, TameIdentStaticSymbolId,
     };