xo-reader2: + DExpectFormalArgSsm [WIP]

2026-01-28 17:40:57 -05:00 · 2026-01-28 17:40:57 -05:00 · 66158551c7
commit 66158551c7
parent 254d7c179d
12 changed files with 679 additions and 16 deletions
--- a/include/xo/reader2/DExpectFormalArgSsm.hpp
+++ b/include/xo/reader2/DExpectFormalArgSsm.hpp
@ -0,0 +1,139 @@
+/** @file DExpectFormalSsm.hpp
+ *
+ *  @author Roland Conybeare, Aug 2024
+ **/
+
+#pragma once
+
+#include "SyntaxStateMachine.hpp"
+//#include <xo/arena/DArena.hpp>
+//#include "exprstate.hpp"
+
+namespace xo {
+    namespace scm {
+        /**
+         *   name : type
+         *  ^    ^ ^
+         *  |    | formal_2
+         *  |    formal_1
+         *  formal_0
+         *
+         *  formal_0 --on_symbol()--> formal_1
+         *  formal_1 --on_colon_token()--> formal_2
+         *  formal_2 --on_typedescr()--> (done)
+         **/
+        enum class formalstatetype {
+            invalid = -1,
+
+            formal_0,
+            formal_1,
+            formal_2,
+
+            n_formalstatetype,
+        };
+
+        extern const char *
+        formalstatetype_descr(formalstatetype x);
+
+        inline std::ostream &
+        operator<< (std::ostream & os, formalstatetype x) {
+            os << formalstatetype_descr(x);
+            return os;
+        }
+
+        /** @class expect_formal_xs
+         *  @brief parser state-machine for a typed formal parameter
+         **/
+        class DExpectFormalArgSsm {
+        public:
+            using TypeDescr = xo::reflect::TypeDescr;
+            using DArena = xo::mm::DArena;
+
+        public:
+            DExpectFormalArgSsm();
+
+            /** create empty instance using memory from @p mm **/
+            DExpectFormalArgSsm * _make(DArena & mm);
+
+            static void start(ParserStateMachine * p_psm);
+
+            /** @defgroup scm-expectformalargssm-ssm-facet syntaxstatemachine facet methods **/
+            ///@{
+
+            /** identifies the ssm implemented here **/
+            syntaxstatetype ssm_type() const noexcept;
+
+            /** mnemonic for expected input (for this ssm) in current state **/
+            std::string_view get_expect_str() const noexcept;
+
+            /** update state on incoming token @p tk,
+             *  with overall parser state in @p p_psm
+             **/
+            void on_token(const Token & tk,
+                          ParserStateMachine * p_psm);
+
+            /** update state on parsed symbol @p sym emitted by nested ssm,
+             *  with overall parser state in @p p_psm
+             **/
+            void on_parsed_symbol(std::string_view sym,
+                                  ParserStateMachine * p_psm);
+
+            /** update state on parsed typedescr @p td emitted by nested ssm,
+             *  with overall parser state in @p p_psm
+             **/
+            void on_parsed_typedescr(TypeDescr td,
+                                     ParserStateMachine * p_psm);
+
+            /** update state on parsed expression emitted by nested ssm
+             *  with overall parser state in @p p_psm
+             **/
+            void on_parsed_expression(obj<AExpression> expr,
+                                      ParserStateMachine * p_psm);
+
+            /** update state on parsed expression, along with following semicolon,
+             *  emitted by nested ssm with overall parser state in @p p_psm
+             **/
+            void on_parsed_expression_with_semicolon(obj<AExpression> expr,
+                                                     ParserStateMachine * p_psm);
+
+            ///@}
+
+#ifdef NOT_YET
+
+            virtual void on_symbol(const std::string & symbol_name,
+                                   parserstatemachine * p_psm) override;
+
+            virtual void on_colon_token(const token_type & tk,
+                                        parserstatemachine * p_psm) override;
+
+            // virtual void on_comma_token(...) override;
+
+#ifdef PROBABLY_NOT
+            virtual void on_rightparen_token(const token_type & tk,
+                                             exprstatestack * p_stack,
+                                             rp<Expression> * p_emit_expr) override;
+#endif
+
+            virtual void on_typedescr(TypeDescr td,
+                                      parserstatemachine * p_psm) override;
+
+            virtual void print(std::ostream & os) const override;
+
+        private:
+            static std::unique_ptr<expect_formal_xs> make();
+#endif
+
+        private:
+            /** parsing state-machine state **/
+            formalstatetype fstate_ = formalstatetype::formal_0;
+
+            /** formal parameter name **/
+            const DUniqueString * name_ = nullptr;
+
+            /** formal parameter type (if specified) **/
+            TypeDescr td_ = nullptr;
+        };
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end DExpectFormalArgSsm.hpp */