From 9a42f02f0c119d6c98e70f0c5c4cbeaaa52e5a54 Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Sun, 18 Aug 2024 23:53:06 -0400
Subject: [PATCH] xo-reader: refactor: simplify expect_expr_xs api

---
 include/xo/reader/expect_expr_xs.hpp | 3 ++-
 src/reader/define_xs.cpp             | 2 +-
 src/reader/expect_expr_xs.cpp        | 9 +++++++--
 src/reader/lambda_xs.cpp             | 2 +-
 src/reader/progress_xs.cpp           | 8 ++++----
 5 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/include/xo/reader/expect_expr_xs.hpp b/include/xo/reader/expect_expr_xs.hpp
index 740eecc8..85686d96 100644
--- a/include/xo/reader/expect_expr_xs.hpp
+++ b/include/xo/reader/expect_expr_xs.hpp
@@ -17,7 +17,7 @@ namespace xo {
         public:
             expect_expr_xs();
 
-            static std::unique_ptr<expect_expr_xs> expect_rhs_expression();
+            static void start(exprstatestack * p_stack);
 
             virtual void on_lambda_token(const token_type & tk,
                                          exprstatestack * p_stack,
@@ -40,6 +40,7 @@ namespace xo {
                                  rp<Expression> * p_emit_expr) override;
 
         private:
+            static std::unique_ptr<expect_expr_xs> make();
         };
 
     } /*namespace scm*/
diff --git a/src/reader/define_xs.cpp b/src/reader/define_xs.cpp
index 96514b97..20ffbd40 100644
--- a/src/reader/define_xs.cpp
+++ b/src/reader/define_xs.cpp
@@ -174,7 +174,7 @@ namespace xo {
             {
                 this->defxs_type_ = defexprstatetype::def_5;
 
-                p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                expect_expr_xs::start(p_stack);
             } else {
                 this->illegal_input_error(self_name, tk);
             }
diff --git a/src/reader/expect_expr_xs.cpp b/src/reader/expect_expr_xs.cpp
index fe4a1830..edc67357 100644
--- a/src/reader/expect_expr_xs.cpp
+++ b/src/reader/expect_expr_xs.cpp
@@ -16,11 +16,16 @@ namespace xo {
     namespace scm {
 
         std::unique_ptr<expect_expr_xs>
-        expect_expr_xs::expect_rhs_expression() {
+        expect_expr_xs::make() {
             return std::make_unique<expect_expr_xs>(expect_expr_xs());
 
         }
 
+        void
+        expect_expr_xs::start(exprstatestack * p_stack) {
+            p_stack->push_exprstate(expect_expr_xs::make());
+        }
+
         expect_expr_xs::expect_expr_xs()
             : exprstate(exprstatetype::expect_rhs_expression)
         {}
@@ -53,7 +58,7 @@ namespace xo {
 
             /* push lparen_0 to remember to look for subsequent rightparen. */
             p_stack->push_exprstate(paren_xs::lparen_0());
-            p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+            expect_expr_xs::start(p_stack);
         }
 
         void
diff --git a/src/reader/lambda_xs.cpp b/src/reader/lambda_xs.cpp
index d6b1eec1..82b91ae2 100644
--- a/src/reader/lambda_xs.cpp
+++ b/src/reader/lambda_xs.cpp
@@ -37,7 +37,7 @@ namespace xo {
             if (lmxs_type_ == lambdastatetype::lm_1) {
                 this->lmxs_type_ = lambdastatetype::lm_2;
                 this->argl_ = argl;
-                p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                expect_expr_xs::start(p_stack);
             } else {
                 exprstate::on_formal_arglist(argl, p_stack, p_emit_expr);
             }
diff --git a/src/reader/progress_xs.cpp b/src/reader/progress_xs.cpp
index 421524a2..93862147 100644
--- a/src/reader/progress_xs.cpp
+++ b/src/reader/progress_xs.cpp
@@ -312,7 +312,7 @@ namespace xo {
                 this->op_type_ = tk2op(tk.tk_type());
 
                 /* infix operator must be followed by non-empty expression */
-                p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                expect_expr_xs::start(p_stack);
             } else if (rhs_) {
                 /* already have complete expression stashed.
                  * behavior depends on operator precedence for tk with stored operator
@@ -341,7 +341,7 @@ namespace xo {
                     p_stack->push_exprstate(progress_xs::make(expr, op2));
 
                     /* infix operator must be followed by non-empty expression */
-                    p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                    expect_expr_xs::start(p_stack);
                 } else {
                     /* e.g.
                      *   6.2 + 4.9 * ...
@@ -360,9 +360,9 @@ namespace xo {
 
                     /* 1. replace with nested incomplete infix exprs */
                     p_stack->push_exprstate(progress_xs::make(lhs_, op_type_));
-                    p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                    expect_expr_xs::start(p_stack);
                     p_stack->push_exprstate(progress_xs::make(rhs_, op2));
-                    p_stack->push_exprstate(expect_expr_xs::expect_rhs_expression());
+                    expect_expr_xs::start(p_stack);
                 }
 
             } else {