From be412cb5aef734f5ee2e4ae99f9b5fbaddd5e92b Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Sat, 10 Aug 2024 16:20:51 -0500
Subject: [PATCH] xo-reader: refactor: + expect_symbol_xs [wip]

---
 include/xo/reader/expect_symbol_xs.hpp | 27 ++++++++++++++++++++++++++
 include/xo/reader/exprstate.hpp        |  2 ++
 src/reader/CMakeLists.txt              |  3 ++-
 src/reader/expect_symbol_xs.cpp        | 23 ++++++++++++++++++++++
 src/reader/exprseq_xs.cpp              |  3 ++-
 src/reader/exprstate.cpp               |  6 ------
 6 files changed, 56 insertions(+), 8 deletions(-)
 create mode 100644 include/xo/reader/expect_symbol_xs.hpp
 create mode 100644 src/reader/expect_symbol_xs.cpp

diff --git a/include/xo/reader/expect_symbol_xs.hpp b/include/xo/reader/expect_symbol_xs.hpp
new file mode 100644
index 00000000..103b89aa
--- /dev/null
+++ b/include/xo/reader/expect_symbol_xs.hpp
@@ -0,0 +1,27 @@
+/* file expect_symbol_xs.hpp
+ *
+ * author: Roland Conybeare, Aug 2024
+ */
+
+#pragma once
+
+#include "exprstate.hpp"
+
+namespace xo {
+    namespace scm {
+        /** @class expect_symbol_xs
+         *  @brief state machine to expect + capture a symbol
+         *
+         *  For example,  lhs in a define-expression
+         **/
+        class expect_symbol_xs : public exprstate {
+        public:
+            expect_symbol_xs();
+
+            static std::unique_ptr<expect_symbol_xs> expect_symbol_expression();
+        };
+    } /*namespace scm*/
+} /*namespace xo*/
+
+
+/* end expect_symbol_xs.hpp */
diff --git a/include/xo/reader/exprstate.hpp b/include/xo/reader/exprstate.hpp
index 9f20dfd8..7f643921 100644
--- a/include/xo/reader/exprstate.hpp
+++ b/include/xo/reader/exprstate.hpp
@@ -70,9 +70,11 @@ namespace xo {
                 {}
             virtual ~exprstate() = default;
 
+#ifdef RELOCATED
             static std::unique_ptr<exprstate> expect_symbol() {
                 return std::make_unique<exprstate>(exprstate(exprstatetype::expect_symbol));
             }
+#endif
             static std::unique_ptr<exprstate> expect_type() {
                 return std::make_unique<exprstate>(exprstate(exprstatetype::expect_type));
             }
diff --git a/src/reader/CMakeLists.txt b/src/reader/CMakeLists.txt
index 77a06a63..473c9a93 100644
--- a/src/reader/CMakeLists.txt
+++ b/src/reader/CMakeLists.txt
@@ -9,7 +9,8 @@ set(SELF_SRCS
     progress_xs.cpp
     paren_xs.cpp
     exprseq_xs.cpp
-    expect_expr_xs.cpp)
+    expect_expr_xs.cpp
+    expect_symbol_xs.cpp)
 
 xo_add_shared_library4(${SELF_LIB} ${PROJECT_NAME}Targets ${PROJECT_VERSION} 1 ${SELF_SRCS})
 xo_dependency(${SELF_LIB} xo_expression)
diff --git a/src/reader/expect_symbol_xs.cpp b/src/reader/expect_symbol_xs.cpp
new file mode 100644
index 00000000..afc8bf6e
--- /dev/null
+++ b/src/reader/expect_symbol_xs.cpp
@@ -0,0 +1,23 @@
+/* file expect_symbol_xs.cpp
+ *
+ * author: Roland Conybeare
+ */
+
+#include "expect_symbol_xs.hpp"
+
+namespace xo {
+    namespace scm {
+        std::unique_ptr<expect_symbol_xs>
+        expect_symbol_xs::expect_symbol_expression() {
+            return std::make_unique<expect_symbol_xs>(expect_symbol_xs());
+        }
+
+        expect_symbol_xs::expect_symbol_xs()
+            : exprstate(exprstatetype::expect_symbol)
+        {}
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+
+/* end expect_symbol_xs.cpp */
diff --git a/src/reader/exprseq_xs.cpp b/src/reader/exprseq_xs.cpp
index 502f129f..042c5eb3 100644
--- a/src/reader/exprseq_xs.cpp
+++ b/src/reader/exprseq_xs.cpp
@@ -2,6 +2,7 @@
 
 #include "exprseq_xs.hpp"
 #include "define_xs.hpp"
+#include "expect_symbol_xs.hpp"
 
 namespace xo {
     namespace scm {
@@ -30,7 +31,7 @@ namespace xo {
             /* todo: replace:
              *   expect_symbol_or_function_signature()
              */
-            p_stack->push_exprstate(exprstate::expect_symbol());
+            p_stack->push_exprstate(expect_symbol_xs::expect_symbol_expression());
 
             /* keyword 'def' introduces a definition:
              *   def pi : f64 = 3.14159265
diff --git a/src/reader/exprstate.cpp b/src/reader/exprstate.cpp
index 540bcaaa..9c083656 100644
--- a/src/reader/exprstate.cpp
+++ b/src/reader/exprstate.cpp
@@ -87,9 +87,6 @@ namespace xo {
                 return false;
 
             case exprstatetype::expect_rhs_expression:
-                /* rhs-expressions (or expressions for that matter)
-                 * may not begin with a colon
-                 */
             case exprstatetype::expect_symbol:
             case exprstatetype::expect_type:
                 return false;
@@ -155,9 +152,6 @@ namespace xo {
                 return false;
 
             case exprstatetype::expect_rhs_expression:
-                /* rhs-expressions (or expressions for that matter)
-                 * may not begin with singleassign '='
-                 */
             case exprstatetype::expect_symbol:
             case exprstatetype::expect_type:
                 return false;