transfering the implementation language to C++

1 files changed, 121 insertions, 0 deletions

diff --git a/model.cpp b/model.cpp
new file mode 100644
index 0000000..11c7a63
--- /dev/null
+++ b/model.cpp
@@ -0,0 +1,121 @@
+#include "model.h"
+
+EmptyList *empty_list = new EmptyList();
+
+EmptyList::EmptyList() : Cons(NULL, NULL) {}
+string EmptyList::ext_repr() { return string("()"); }
+#ifdef DEBUG
+string EmptyList::_debug_repr() { return ext_repr(); }
+#endif
+
+bool FrameObj::is_ret_addr() { 
+    return ftype == CLS_RET_ADDR;
+}
+
+EvalObj::EvalObj() : FrameObj() { ftype = CLS_EVAL_OBJ; }
+void EvalObj::prepare(Cons *pc) {}
+bool EvalObj::is_simple_obj() {
+    return otype == CLS_SIM_OBJ;
+}
+
+bool EvalObj::is_true() {
+    return true;
+}
+
+Cons::Cons(EvalObj *_car, Cons *_cdr) : EvalObj(), car(_car), cdr(_cdr), skip(false), next(NULL) {}
+
+string Cons::ext_repr() { return string("#<Cons>"); }
+#ifdef DEBUG
+string Cons::_debug_repr() { return ext_repr(); }
+Cons::_debug_print() {
+    printf("%s",
+    ("car: " + car -> ext_repr() + "\n" + \
+     "cdr: " + cdr -> ext_repr() + "\n").c_str());
+}
+#endif
+
+RetAddr::RetAddr(Cons *_addr) : FrameObj(), addr(_addr) {
+    ftype = CLS_RET_ADDR;
+}
+
+UnspecObj::UnspecObj() : EvalObj() {}
+string UnspecObj::ext_repr() { return string("#<Unspecified>"); }
+#ifdef DEBUG
+string UnspecObj::_debug_repr() { return ext_repr(); }
+#endif
+
+SymObj::SymObj(string str) : EvalObj(), val(str) {}
+string SymObj::ext_repr() { return "#<Symbol: " + val + ">"; }
+#ifdef DEBUG
+string SymObj::_debug_repr() { return ext_repr(); }
+#endif
+
+OptObj::OptObj() : EvalObj() {}
+
+ProcObj::ProcObj(ASTList *_body, 
+                    Environment *_envt, 
+                    SymbolList *_para_list) :
+    OptObj(), body(_body), envt(_envt), para_list(_para_list) {}
+
+Cons *ProcObj::call(ArgList *arg_list, Environment * &envt,
+                    Continuation * &cont, FrameObj ** &top_ptr) {
+    // Create a new continuation
+    Cons *ret_addr = dynamic_cast<Cons*>(*top_ptr);
+    Continuation *ncont = new Continuation(envt, ret_addr, cont, body);
+    cont = ncont;                   // Add to the cont chain
+    envt = new Environment(envt);   // Create local env and recall the closure
+    // TODO: Compare the arguments to the parameters
+    for (Cons *ptr = arg_list->cdr, *ppar = para_list; 
+            ptr != empty_list; ptr = ptr->cdr)
+        envt->add_binding(dynamic_cast<SymObj*>(ppar->car), ptr->car);
+    *top_ptr = new RetAddr(NULL);   // Mark the entrance of a cont
+    return body;                    // Move pc to the proc entry point
+}
+
+string ProcObj::ext_repr() { return string("#<Procedure"); }
+#ifdef DEBUG
+string ProcObj::_debug_repr() { return ext_repr(); }
+#endif
+
+SpecialOptObj::SpecialOptObj() : OptObj() {}
+
+NumberObj::NumberObj() : EvalObj() {}
+
+BuiltinProcObj::BuiltinProcObj(BuiltinProc f, string _name) :
+    OptObj(), handler(f), name(_name) {}
+
+Cons *BuiltinProcObj::call(ArgList *arg_list, Environment * &envt,
+                                Continuation * &cont, FrameObj ** &top_ptr) {
+
+    Cons *ret_addr = dynamic_cast<Cons*>(*top_ptr);
+    *top_ptr = handler(arg_list->cdr);
+    return ret_addr->next;          // Move to the next instruction
+}
+
+Environment::Environment(Environment *_prev_envt) : prev_envt(_prev_envt) {}
+void Environment::add_binding(SymObj *sym_obj, EvalObj *eval_obj) {
+    binding[sym_obj->val] = eval_obj;
+}
+EvalObj *Environment::get_obj(SymObj *sym_obj) {
+    string name(sym_obj->val);
+    for (Environment *ptr = this; ptr; ptr = prev_envt)
+    {
+        bool has_key = binding.count(name);
+        if (has_key) return binding[name];
+    }
+    //TODO: exc key not found
+}
+bool Environment::has_obj(SymObj *sym_obj) {
+    string name(sym_obj->val);
+    for (Environment *ptr = this; ptr; ptr = prev_envt)
+        if (binding.count(name))
+            return true;
+    return false;
+}
+
+Continuation::Continuation(Environment *_envt, Cons *_pc, 
+                            Continuation *_prev_cont, 
+                            ASTList *_proc_body, 
+                            unsigned int _body_cnt) : 
+        envt(_envt), pc(_pc), prev_cont(_prev_cont), 
+        proc_body(_proc_body), body_cnt(_body_cnt) {}