src/c/scheme.h

   1 /* scheme.h
   2  * A header file that defines the basic Scheme data types, etc. Used
   3  * with the scheme->c compiler.
   4  * Programmer: Mayer Goldberg, 2000
   5  */
   6
   7 #ifndef __SCHEME_H
   8 #define __SCHEME_H
   9
  10 #ifndef NULL
  11 #define NULL ((void *)0)
  12 #endif
  13
  14 typedef enum SchemeType {
  15   SCHEME_VOID,
  16     SCHEME_TYPE_FIRST = SCHEME_VOID,
  17   SCHEME_INT,
  18   SCHEME_CHAR,
  19   SCHEME_BOOL,
  20   SCHEME_STRING,
  21   SCHEME_NIL,
  22   SCHEME_PAIR,
  23   SCHEME_VECTOR,
  24   SCHEME_SYMBOL,
  25   SCHEME_CLOSURE,
  26   SCHEME_TYPE_END /* not to be used */
  27 } SchemeType;
  28
  29 /* basic support for scheme objects */
  30
  31 typedef struct SchemeIntData {
  32   int value;
  33 } SchemeIntData;
  34
  35 typedef struct SchemeCharData {
  36   char value;
  37 } SchemeCharData;
  38
  39 typedef struct SchemeBoolData {
  40   int value;
  41 } SchemeBoolData;
  42
  43 typedef struct SchemeStringData {
  44   int length;
  45   char *value;
  46 } SchemeStringData;
  47
  48 typedef struct SchemePairData {
  49   struct SchemeObject *car, *cdr;
  50 } SchemePairData;
  51
  52 typedef struct SchemeVectorData {
  53   int length;
  54   struct SchemeObject **vec;
  55 } SchemeVectorData;
  56
  57 typedef struct SchemeSymbolData {
  58   struct SymbolEntry *sep;
  59 } SchemeSymbolData;
  60
  61 typedef struct SchemeClosureData {
  62   struct SchemeObject **env;
  63   void *code;
  64 } SchemeClosureData;
  65
  66 typedef union SchemeObjectData {
  67   struct SchemeIntData sid;
  68   struct SchemeCharData scd;
  69   struct SchemeBoolData sbd;
  70   struct SchemeStringData ssd;
  71   struct SchemePairData spd;
  72   struct SchemeVectorData svd;
  73   struct SchemeSymbolData smd;
  74   struct SchemeClosureData scld;
  75 } SchemeObjectData;
  76
  77 typedef struct SchemeObject {
  78   SchemeType type;
  79   SchemeObjectData *schemeObjectData;
  80 } SchemeObject;
  81
  82 #define VOID(x)                  ((void *) (x))
  83 #define SOB(x)                   ((SchemeObject *) (x))
  84 #define SOD(x)                   ((SchemeObjectData *) (x))
  85 #define SOB_TYPE(x)              SOB((x))->type
  86 #define SOB_DATA(x)              SOB((x))->schemeObjectData
  87
  88 #define IS_SOB_VOID(x)           (SOB((x))->type == SCHEME_VOID)
  89 #define IS_SOB_INT(x)            (SOB((x))->type == SCHEME_INT)
  90 #define IS_SOB_CHAR(x)           (SOB((x))->type == SCHEME_CHAR)
  91 #define IS_SOB_BOOL(x)           (SOB((x))->type == SCHEME_BOOL)
  92 #define IS_SOB_STRING(x)         (SOB((x))->type == SCHEME_STRING)
  93 #define IS_SOB_NIL(x)            (SOB((x))->type == SCHEME_NIL)
  94 #define IS_SOB_PAIR(x)           (SOB((x))->type == SCHEME_PAIR)
  95 #define IS_SOB_VECTOR(x)         (SOB((x))->type == SCHEME_VECTOR)
  96 #define IS_SOB_SYMBOL(x)         (SOB((x))->type == SCHEME_SYMBOL)
  97 #define IS_SOB_CLOSURE(x)        (SOB((x))->type == SCHEME_CLOSURE)
  98
  99 #define SOB_INT_VALUE(x)           SOB_DATA((x))->sid.value
 100 #define SOB_CHAR_VALUE(x)          SOB_DATA((x))->scd.value
 101 #define SOB_BOOL_VALUE(x)          SOB_DATA((x))->sbd.value
 102 #define SOB_STRING_LENGTH(x)       SOB_DATA((x))->ssd.length
 103 #define SOB_STRING_VALUE(x)        SOB_DATA((x))->ssd.value
 104 #define SOB_STRING_REF(x, i)       SOB_STRING_VALUE((x))[i]
 105 #define SOB_STRING_SET(x, i, c)    SOB_STRING_VALUE((x))[i] = c
 106 #define SOB_PAIR_CAR(x)            SOB_DATA((x))->spd.car
 107 #define SOB_PAIR_CDR(x)            SOB_DATA((x))->spd.cdr
 108 #define SOB_VECTOR_LENGTH(x)       SOB_DATA((x))->svd.length
 109 #define SOB_VECTOR_VALUE(x)        SOB_DATA((x))->svd.vec
 110 #define SOB_VECTOR_REF(x, i)       SOB_VECTOR_VALUE((x))[i]
 111 #define SOB_VECTOR_SET(x, i, sob)  SOB_VECTOR_VALUE((x))[i] = sob
 112 #define SOB_SYMBOL_ENTRY(x)        SOB_DATA((x))->smd.sep
 113 #define SOB_SYMBOL_HAS_VALUE(x)    SOB_SYMBOL_ENTRY((x))->isDefined
 114 #define SOB_SYMBOL_NAME(x)         SOB_SYMBOL_ENTRY((x))->name
 115 #define SOB_SYMBOL_VALUE(x)        SOB_SYMBOL_ENTRY((x))->sob
 116 #define SOB_CLOSURE_ENV(x)         SOB_DATA((x))->scld.env
 117 #define SOB_CLOSURE_CODE(x)        SOB_DATA((x))->scld.code
 118
 119 #define SOB_BOOL_FALSE(x) (IS_SOB_BOOL(x) && (SOB_BOOL_VALUE(x) == 0))
 120
 121 SchemeObject *makeSchemeObject();
 122 SchemeObject *makeSchemeVoid();
 123 SchemeObject *makeSchemeInt(int n);
 124 SchemeObject *makeSchemeChar(char c);
 125 SchemeObject *makeSchemeBool(int b);
 126 SchemeObject *makeSchemeString(int n, char c);
 127 SchemeObject *makeSchemeStringFromCString(char *s);
 128 SchemeObject *makeSchemeNil();
 129 SchemeObject *makeSchemePair(SchemeObject *car, SchemeObject *cdr);
 130 SchemeObject *makeSchemeVectorInit(int n, SchemeObject *initSob);
 131 SchemeObject *makeSchemeSymbol(char *s);
 132 SchemeObject *makeSchemeClosure(void* env,void* code);
 133
 134 char *sobToString(SchemeObject *sob);
 135
 136 /* I am too lazy to think up a good hash function, so I'm not using a
 137  * hash table but rather a binary tree. Of course, the performance for
 138  * free variable look up will not be as good, but the implementation
 139  * details are hidden behind an API, and can therefore be changed
 140  * later.
 141  */
 142
 143 typedef struct SymbolEntry {
 144   char *name;
 145   int isDefined;
 146   SchemeObject *sob;
 147 } SymbolEntry;
 148
 149 typedef struct SymbolNode {
 150   SymbolEntry *sym;
 151   struct SymbolNode *left, *right;
 152 } SymbolNode;
 153
 154 #define SYM_ENTRY(symNode)     ((SymbolNode *)symNode)->sym
 155 #define SYM_NAME(symNode)      SYM_ENTRY((symNode))->name
 156 #define SYM_HAS_VALUE(symNode) SYM_ENTRY((symNode))->isDefined
 157 #define SYM_VALUE(symNode)     SYM_ENTRY((symNode))->sob
 158 #define SYM_LEFT(symNode)      ((symNode))->left
 159 #define SYM_RIGHT(symNode)     ((symNode))->right
 160
 161 SymbolEntry *probeSymbolDefined(char *name, SymbolNode *t);
 162 SymbolEntry *getSymbol(char *name, SymbolNode *t);
 163
 164 /* this is intended for future support for the garbage collector */
 165
 166 void *autoMalloc(int n);
 167 void autoFree(void *p);
 168
 169 /* this is the name of the function created by our compiler */
 170
 171 void schemeCompiledFunction();
 172
 173 #endif