From 04f79eaf013ba9f64bb2107d54bc61a51a97bfad Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Fri, 9 Aug 2024 14:10:16 -0400
Subject: [PATCH] xo-reader: wip: + exprseq_xs class

---
 include/xo/reader/exprseq_xs.hpp | 28 +++++++++++++++++++++++++++
 src/reader/CMakeLists.txt        |  3 ++-
 src/reader/exprseq_xs.cpp        | 33 ++++++++++++++++++++++++++++++++
 src/reader/exprstate.cpp         |  2 ++
 4 files changed, 65 insertions(+), 1 deletion(-)
 create mode 100644 include/xo/reader/exprseq_xs.hpp
 create mode 100644 src/reader/exprseq_xs.cpp

diff --git a/include/xo/reader/exprseq_xs.hpp b/include/xo/reader/exprseq_xs.hpp
new file mode 100644
index 00000000..28a17088
--- /dev/null
+++ b/include/xo/reader/exprseq_xs.hpp
@@ -0,0 +1,28 @@
+/** @file exprseq_xs.hpp
+ *
+ *  Author: Roland Conybeare
+ **/
+
+#pragma once
+
+#include "exprstate.hpp"
+//#include <cstdint>
+
+namespace xo {
+    namespace scm {
+        /** @class exprseq_xs
+         *  @brief parsing state-machine for top-level expression sequence
+         *
+         **/
+        class exprseq_xs : public exprstate {
+        public:
+            // ----- token input methods -----
+
+            virtual void on_def_token(const token_type & tk,
+                                      exprstatestack * p_stack) override;
+        };
+    } /*namespace scm*/
+} /*namespace xo*/
+
+
+/** end exprseq_xs.hpp **/
diff --git a/src/reader/CMakeLists.txt b/src/reader/CMakeLists.txt
index 4741fa3d..e75e248a 100644
--- a/src/reader/CMakeLists.txt
+++ b/src/reader/CMakeLists.txt
@@ -7,7 +7,8 @@ set(SELF_SRCS
     exprstate.cpp
     define_xs.cpp
     progress_xs.cpp
-    paren_xs.cpp)
+    paren_xs.cpp
+    exprseq_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/exprseq_xs.cpp b/src/reader/exprseq_xs.cpp
new file mode 100644
index 00000000..012e9b2e
--- /dev/null
+++ b/src/reader/exprseq_xs.cpp
@@ -0,0 +1,33 @@
+/* @file exprseq_xs.cpp */
+
+#include "exprseq_xs.hpp"
+#include "define_xs.hpp"
+
+namespace xo {
+    namespace scm {
+        void
+        exprseq_xs::on_def_token(const token_type & /*tk*/,
+                                 exprstatestack * p_stack)
+        {
+            constexpr bool c_debug_flag = true;
+            scope log(XO_DEBUG(c_debug_flag));
+
+            //constexpr const char * c_self_name = "exprseq_xs::on_def_token";
+
+            p_stack->push_exprstate(define_xs::def_0());
+
+            /* todo: replace:
+             *   expect_symbol_or_function_signature()
+             */
+            p_stack->push_exprstate(exprstate::expect_symbol());
+
+            /* keyword 'def' introduces a definition:
+             *   def pi : f64 = 3.14159265
+             *   def sq(x : f64) -> f64 { (x * x) }
+             */
+        }
+    } /*namespace scm*/
+} /*namespace xo*/
+
+
+/* end exprseq_xs.cpp */
diff --git a/src/reader/exprstate.cpp b/src/reader/exprstate.cpp
index d6242730..6116b349 100644
--- a/src/reader/exprstate.cpp
+++ b/src/reader/exprstate.cpp
@@ -41,6 +41,7 @@ namespace xo {
             return "???";
         }
 
+#ifdef OBSOLETE
         bool
         exprstate::admits_definition() const {
             switch (exs_type_) {
@@ -69,6 +70,7 @@ namespace xo {
 
             return false;
         }
+#endif
 
         bool
         exprstate::admits_symbol() const {