diff options
Diffstat (limited to 'model.h')
| -rw-r--r-- | model.h | 100 |
1 files changed, 79 insertions, 21 deletions
@@ -21,10 +21,23 @@ static const int CLS_CONS_OBJ = 1; */ class FrameObj { protected: - ClassType ftype; // avoid the use of dynamic_cast to improve efficiency + /** + * Report the type of the FrameObj, which can avoid the use of + * dynamic_cast to improve efficiency. See the constructor for detail + */ + ClassType ftype; public: - FrameObj(ClassType); + /** + * Construct an EvalObj + * @param ftype the type of the FrameObj (CLS_EVAL_OBJ for an EvalObj, + * CLS_RET_ADDR for a return address) + */ + FrameObj(ClassType ftype); virtual ~FrameObj() {} + /** + * Tell whether the object is a return address, according to ftype + * @return true for yes + */ bool is_ret_addr(); #ifdef DEBUG virtual string _debug_repr() = 0; @@ -37,15 +50,30 @@ class Cons; * Objects that represents a value in evaluation */ class EvalObj : public FrameObj { + protected: + /** + * Report the type of the EvalObj, which can avoid the use of + * dynamic_cast to improve efficiency. See the constructor for detail + */ + ClassType otype; public: - ClassType otype; // avoid the use of dynamic_cast to improve efficiency - - EvalObj(ClassType _otype = CLS_SIM_OBJ); + /** + * Construct an EvalObj + * @param otype the type of the EvalObj (CLS_CONS_OBJ for a + * construction, CLS_SIM_OBJ for a simple object), which defaults to + * CLS_SIM_OBJ + */ + EvalObj(ClassType otype = CLS_SIM_OBJ); + /** Check if the object is a simple object (instead of a call + * invocation) + * @return true if the object is not a construction (Cons) + * */ bool is_simple_obj(); /** External representation of this object */ virtual void prepare(Cons *pc); + /** Any EvalObj has its external representation */ virtual string ext_repr() = 0; - /**< Always true for all EvalObjs except BoolObj */ + /** Always true for all EvalObjs except BoolObj */ virtual bool is_true(); #ifdef DEBUG virtual void _debug_print(); @@ -62,9 +90,9 @@ class Cons : public EvalObj { EvalObj *car; /**< car (as in Scheme) */ Cons *cdr; /**< cdr (as in Scheme) */ bool skip; /**< Wether to skip the current branch */ - Cons* next; /**< The next branch in effect */ + Cons* next; /**< The next branch in effect */ - Cons(EvalObj *, Cons *); + Cons(EvalObj *car, Cons *cdr); /**< Create a Cons (car . cdr) */ #ifdef DEBUG void _debug_print(); string _debug_repr(); @@ -90,9 +118,12 @@ class EmptyList: public Cons { class RetAddr : public FrameObj { public: Cons* addr; /**< The return address */ - - RetAddr(Cons *); + /** Constructs a return address object which refers to the node addr in + * the AST */ + RetAddr(Cons *addr); +#ifdef DEBUG string _debug_repr(); +#endif }; @@ -159,7 +190,8 @@ class ProcObj: public OptObj { /** Pointer to the environment */ Environment *envt; - ProcObj(ASTList *, Environment *, SymbolList *); + /** Conctructs a ProcObj */ + ProcObj(ASTList *body, Environment *envt, SymbolList *para_list); Cons *call(ArgList *args, Environment * &envt, Continuation * &cont, FrameObj ** &top_ptr); #ifdef DEBUG @@ -186,7 +218,12 @@ class BuiltinProcObj: public OptObj { BuiltinProc handler; string name; public: - BuiltinProcObj(BuiltinProc, string); + /** + * Make a BuiltinProcObj which invokes proc when called + * @param proc the actual handler + * @param name the name of this built-in procedure + */ + BuiltinProcObj(BuiltinProc proc, string name); Cons *call(ArgList *args, Environment * &envt, Continuation * &cont, FrameObj ** &top_ptr); #ifdef DEBUG @@ -210,25 +247,46 @@ typedef map<string, EvalObj*> Str2EvalObj; */ class Environment { private: - Environment *prev_envt; /**< Pointer to the upper level environment */ + Environment *prev_envt; /**< Pointer to the upper-level environment */ Str2EvalObj binding; /**< Store all pairs of identifier and its corresponding obj */ public: - Environment(Environment * = NULL); - void add_binding(SymObj *, EvalObj *); - EvalObj *get_obj(EvalObj *); + /** Create an runtime environment + * @param prev_envt the outer environment + * */ + Environment(Environment *prev_envt); + /** Add a binding entry which binds sym_obj to eval_obj */ + void add_binding(SymObj *sym_obj, EvalObj *eval_obj); + /** Extract the corresponding EvalObj if obj is a SymObj, or just + * simply return obj as it is + * @param obj the object as request + * */ + EvalObj *get_obj(EvalObj *obj); + /** Check if the desired obj exists + * @return true for yes + */ bool has_obj(SymObj *); }; +/** @class Continuation + * Save the registers and necessary information when a user-defined call is + * being made (Behave like a stack frame in C). When the call has accomplished, + * the system will restore all the registers according to the continuation. + */ class Continuation { public: - Continuation *prev_cont; - Environment *envt; - Cons *pc; + /** Linking the previous continuation on the chain */ + Continuation *prev_cont; + Environment *envt; /**< The saved envt */ + Cons *pc; /**< The saved pc */ + /** Pointing to the current expression that is being evaluated. + * When its value goes to empty_list, the call is accomplished. + */ ASTList *proc_body; - Continuation(Environment *, Cons *, Continuation *, - ASTList *); + /** Create a continuation */ + Continuation(Environment *envt, Cons *pc, Continuation *prev_cont, + ASTList *proc_body); }; #endif |