xo-expression/xo-reader: refactor Environment -> SymbolTable

2025-11-19 12:42:31 -05:00 · 2025-11-19 12:42:31 -05:00 · 800928cd69
commit 800928cd69
parent cfca87ee44
40 changed files with 146 additions and 510 deletions
--- a/xo-expression/src/expression/LocalSymtab.cpp
+++ b/xo-expression/src/expression/LocalSymtab.cpp
@ -0,0 +1,135 @@
+/* file LocalSymtab.cpp
+ *
+ * author: Roland Conybeare
+ */
+
+#include "LocalSymtab.hpp"
+#include "pretty_variable.hpp"
+#include "xo/indentlog/print/pretty_vector.hpp"
+#include "xo/indentlog/print/vector.hpp"
+
+
+namespace xo {
+    namespace scm {
+        rp<LocalSymtab>
+        LocalSymtab::make_empty() {
+            return new LocalSymtab(std::vector<rp<Variable>>(), nullptr);
+        }
+
+        rp<LocalSymtab>
+        LocalSymtab::make(const std::vector<rp<Variable>> & argv,
+                       const rp<SymbolTable> & parent_env)
+        {
+            return new LocalSymtab(argv, parent_env);
+        }
+
+        rp<LocalSymtab>
+        LocalSymtab::make1(const rp<Variable> & arg1,
+                        const rp<SymbolTable> & parent_env)
+        {
+            std::vector<rp<Variable>> argv = { arg1 };
+
+            return make(argv, parent_env);
+        }
+
+        LocalSymtab::LocalSymtab(const std::vector<rp<Variable>> & argv,
+                           const rp<SymbolTable> & parent_env)
+            : origin_{nullptr},
+              argv_(argv),
+              parent_env_{parent_env}
+        {
+            constexpr bool c_debug_flag = true;
+            scope log(XO_DEBUG(c_debug_flag), xtag("this", (void*)this), xtag("argv", argv_));
+        }
+
+        binding_path
+        LocalSymtab::lookup_local_binding(const std::string & vname) const {
+            int j_slot = 0;
+            for (const auto & arg : argv_) {
+                if (arg->name() == vname)
+                    return { 0 /*i_link*/, j_slot };
+                ++j_slot;
+            }
+
+            return { -2 /*i_link: sentinel*/, 0 };
+        } /*lookup_local_binding*/
+
+        binding_path
+        LocalSymtab::lookup_binding(const std::string & vname) const {
+            {
+                auto local = this->lookup_local_binding(vname);
+                if (local.i_link_ == 0)
+                    return local;
+            }
+
+            auto free = parent_env_->lookup_binding(vname);
+
+            if (free.i_link_ == -1)
+                return free;
+            else
+                return { free.i_link_ + 1, free.j_slot_ };
+        } /*lookup_binding*/
+
+        void
+        LocalSymtab::assign_parent(bp<SymbolTable> p) {
+            if ((parent_env_.get() != nullptr) && (parent_env_.get() != p.get())) {
+                throw std::runtime_error(tostr("LocalSymtab::assign_parent(P2): already have established parent P1",
+                                               xtag("P1", parent_env_),
+                                               xtag("P2", p)));
+
+                assert(false);
+            }
+
+            parent_env_ = p.promote();
+        }
+
+        void
+        LocalSymtab::upsert_local(bp<Variable> target) {
+            for (auto & var : this->argv_)  {
+                if (var->name() == target->name()) {
+                    /* replace existing variable.  This may change its type */
+                    var = target.promote();
+                    return;
+                }
+            }
+
+            /* control here: target not already present in this frame -> append */
+
+            this->argv_.push_back(target.promote());
+        }
+
+        void
+        LocalSymtab::print(std::ostream& os) const {
+            os << "<LocalSymtab"
+               << xtag("argv", argv_)
+               << ">";
+        }
+
+        std::uint32_t
+        LocalSymtab::pretty_print(const xo::print::ppindentinfo & ppii) const {
+            using xo::print::ppstate;
+
+            ppstate * pps = ppii.pps();
+
+            if (ppii.upto()) {
+                if (!pps->print_upto("<LocalSymtab"))
+                    return false;
+                if (!pps->print_upto_tag("argv", argv_))
+                    return false;
+                pps->write(">");
+
+                return true;
+            } else {
+                pps->write("<LocalSymtab");
+                pps->newline_pretty_tag(ppii.ci1(), "this", (void*)this);
+                pps->newline_pretty_tag(ppii.ci1(), "argv", argv_);
+                pps->write(">");
+
+                return false;
+            }
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end LocalSymtab.cpp */