Add 'xo-reader/' from commit 'c46c0f1cc4'

git-subtree-dir: xo-reader
git-subtree-mainline: dacdeb2cd7
git-subtree-split: c46c0f1cc4

xo-reader/src/reader/exprseq_xs.cpp

@@ -0,0 +1,81 @@
+/* @file exprseq_xs.cpp */
+
+#include "exprseq_xs.hpp"
+#include "parserstatemachine.hpp"
+#include "exprstatestack.hpp"
+#include "define_xs.hpp"
+#include "expect_symbol_xs.hpp"
+
+namespace xo {
+    namespace scm {
+        std::unique_ptr<exprseq_xs>
+        exprseq_xs::make()
+        {
+            return std::make_unique<exprseq_xs>(exprseq_xs());
+        }
+
+        void
+        exprseq_xs::start(parserstatemachine * p_psm)
+        {
+            p_psm->push_exprstate(exprseq_xs::make());
+        }
+
+        exprseq_xs::exprseq_xs()
+            : exprstate(exprstatetype::expect_toplevel_expression_sequence)
+        {
+        }
+
+        void
+        exprseq_xs::on_def_token(const token_type & /*tk*/,
+                                 parserstatemachine * p_psm)
+        {
+            constexpr bool c_debug_flag = true;
+            scope log(XO_DEBUG(c_debug_flag));
+
+            //constexpr const char * c_self_name = "exprseq_xs::on_def_token";
+
+            define_xs::start(p_psm);
+
+            /* keyword 'def' introduces a definition:
+             *   def pi : f64 = 3.14159265
+             *   def sq(x : f64) -> f64 { (x * x) }
+             */
+        }
+
+        void
+        exprseq_xs::on_symbol_token(const token_type & tk,
+                                    parserstatemachine * /*p_psm*/)
+        {
+            constexpr const char * c_self_name = "exprseq_xs::on_symbol_token";
+
+            this->illegal_input_error(c_self_name, tk);
+        }
+
+        void
+        exprseq_xs::on_typedescr(TypeDescr /*td*/,
+                                 parserstatemachine * /*p_psm*/)
+        {
+            /* unreachable - typedescr should never get delivered to exprseq */
+            assert(false);
+            return;
+        }
+
+        void
+        exprseq_xs::on_expr(ref::brw<Expression> expr,
+                            parserstatemachine * p_psm)
+        {
+            /* toplevel expression sequence accepts an
+             * arbitrary number of expressions.
+             *
+             * parser::include_token() returns
+             */
+
+            auto p_emit_expr = p_psm->p_emit_expr_;
+
+            *p_emit_expr = expr.promote();
+        } /*on_expr*/
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end exprseq_xs.cpp */