refactor: integrate compilation-owned identifier interning

source/strpool/strpool.hon

@@ -4,13 +4,11 @@ import "@std/hashmap"
 
 InternError :: enum { out_of_space }
 
+#! identifies a string only within its owning pool.
 StringId :: alias u32
 
 no_str :: maxval!(StringId)
 
-#! global pool owned by main.hon; initialize before scanning and release with deinit.
-strings StringPool := undefined
-
 #! retains its allocator and owns interned copies; release all storage with deinit.
 StringPool :: struct {
     ids hashmap.StringHashMap(StringId) # string → id

source/strpool/strpool.test.hon

@@ -22,3 +22,19 @@ handles_interning test {
     try testing.expect_equal(null, invalid_str)
     try testing.expect_equal("hello", hello_str?)
 }
+
+keeps_independent_pool_ids_local test {
+    first := init(mem.c_allocator)
+    defer deinit(&first)
+    second := init(mem.c_allocator)
+    defer deinit(&second)
+    hello :: try intern(&first, "hello")
+    world :: try intern(&second, "world")
+    try testing.expect_equal(hello, world)
+    try testing.expect_equal("hello", get_str(&first, hello)?)
+    try testing.expect_equal("world", get_str(&second, world)?)
+    different :: try intern(&first, "world")
+    try testing.expect(different != hello)
+    try testing.expect_equal(hello, try intern(&first, "hello"))
+    try testing.expect_equal(world, try intern(&second, "world"))
+}