48 |
typedef struct stackitem_struct |
typedef struct stackitem_struct |
49 |
{ |
{ |
50 |
value *item; /* The value on the stack */ |
value *item; /* The value on the stack */ |
51 |
|
/* (This is never NULL) */ |
52 |
struct stackitem_struct *next; /* Next item */ |
struct stackitem_struct *next; /* Next item */ |
53 |
} stackitem; |
} stackitem; |
54 |
|
|
439 |
env->head->next= temp; |
env->head->next= temp; |
440 |
} |
} |
441 |
|
|
442 |
|
/* Rotate the first three elements on the stack. */ |
443 |
|
extern void rot(environment *env) |
444 |
|
{ |
445 |
|
stackitem *temp= env->head; |
446 |
|
|
447 |
|
if(env->head==NULL || env->head->next==NULL |
448 |
|
|| env->head->next->next==NULL) { |
449 |
|
printerr("Too Few Arguments"); |
450 |
|
env->err=1; |
451 |
|
return; |
452 |
|
} |
453 |
|
|
454 |
|
env->head= env->head->next->next; |
455 |
|
temp->next->next= env->head->next; |
456 |
|
env->head->next= temp; |
457 |
|
} |
458 |
|
|
459 |
/* Recall a value from a symbol, if bound */ |
/* Recall a value from a symbol, if bound */ |
460 |
extern void rcl(environment *env) |
extern void rcl(environment *env) |
461 |
{ |
{ |
966 |
if(env->err) return; |
if(env->err) return; |
967 |
push_int(&(env->head), a+b); |
push_int(&(env->head), a+b); |
968 |
} |
} |
969 |
|
|
970 |
|
/* Return copy of a value */ |
971 |
|
value *copy_val(value *old_value){ |
972 |
|
stackitem *old_item, *new_item, *prev_item; |
973 |
|
|
974 |
|
value *new_value=malloc(sizeof(value)); |
975 |
|
|
976 |
|
new_value->type=old_value->type; |
977 |
|
new_value->refcount=0; /* This is increased if/when this |
978 |
|
value is referenced somewhere, like |
979 |
|
in a stack item or a variable */ |
980 |
|
switch(old_value->type){ |
981 |
|
case integer: |
982 |
|
new_value->content.val=old_value->content.val; |
983 |
|
break; |
984 |
|
case string: |
985 |
|
(char *)(new_value->content.ptr) |
986 |
|
= strdup((char *)(old_value->content.ptr)); |
987 |
|
break; |
988 |
|
case func: |
989 |
|
case symb: |
990 |
|
new_value->content.ptr=old_value->content.ptr; |
991 |
|
break; |
992 |
|
case list: |
993 |
|
new_value->content.ptr=NULL; |
994 |
|
|
995 |
|
prev_item=NULL; |
996 |
|
old_item=(stackitem *)(old_value->content.ptr); |
997 |
|
|
998 |
|
while(old_item != NULL) { /* While list is not empty */ |
999 |
|
new_item= malloc(sizeof(stackitem)); |
1000 |
|
new_item->item=copy_val(old_item->item); /* recurse */ |
1001 |
|
new_item->next=NULL; |
1002 |
|
if(prev_item != NULL) /* If this wasn't the first item */ |
1003 |
|
prev_item->next=new_item; /* point the previous item to the |
1004 |
|
new item */ |
1005 |
|
else |
1006 |
|
new_value->content.ptr=new_item; |
1007 |
|
old_item=old_item->next; |
1008 |
|
prev_item=new_item; |
1009 |
|
} |
1010 |
|
break; |
1011 |
|
} |
1012 |
|
return new_value; |
1013 |
|
} |
1014 |
|
|
1015 |
|
/* duplicates an item on the stack */ |
1016 |
|
extern void dup(environment *env) { |
1017 |
|
if((env->head)==NULL) { |
1018 |
|
printerr("Too Few Arguments"); |
1019 |
|
env->err=1; |
1020 |
|
return; |
1021 |
|
} |
1022 |
|
push_val(&(env->head), copy_val(env->head->item)); |
1023 |
|
} |
1024 |
|
|
1025 |
|
/* If-Then */ |
1026 |
|
extern void sx_6966(environment *env) { |
1027 |
|
|
1028 |
|
int truth; |
1029 |
|
|
1030 |
|
if((env->head)==NULL || env->head->next==NULL) { |
1031 |
|
printerr("Too Few Arguments"); |
1032 |
|
env->err=1; |
1033 |
|
return; |
1034 |
|
} |
1035 |
|
|
1036 |
|
if(env->head->next->item->type != integer) { |
1037 |
|
printerr("Bad Argument Type"); |
1038 |
|
env->err=2; |
1039 |
|
return; |
1040 |
|
} |
1041 |
|
|
1042 |
|
swap(env); |
1043 |
|
if(env->err) return; |
1044 |
|
|
1045 |
|
truth=env->head->item->content.val; |
1046 |
|
|
1047 |
|
toss(env); |
1048 |
|
if(env->err) return; |
1049 |
|
|
1050 |
|
if(truth) |
1051 |
|
eval(env); |
1052 |
|
else |
1053 |
|
toss(env); |
1054 |
|
} |
1055 |
|
|
1056 |
|
/* If-Then-Else */ |
1057 |
|
extern void ifelse(environment *env) { |
1058 |
|
|
1059 |
|
int truth; |
1060 |
|
|
1061 |
|
if((env->head)==NULL || env->head->next==NULL |
1062 |
|
|| env->head->next->next==NULL) { |
1063 |
|
printerr("Too Few Arguments"); |
1064 |
|
env->err=1; |
1065 |
|
return; |
1066 |
|
} |
1067 |
|
|
1068 |
|
if(env->head->next->next->item->type != integer) { |
1069 |
|
printerr("Bad Argument Type"); |
1070 |
|
env->err=2; |
1071 |
|
return; |
1072 |
|
} |
1073 |
|
|
1074 |
|
rot(env); |
1075 |
|
if(env->err) return; |
1076 |
|
|
1077 |
|
truth=env->head->item->content.val; |
1078 |
|
|
1079 |
|
toss(env); |
1080 |
|
if(env->err) return; |
1081 |
|
|
1082 |
|
if(!truth) |
1083 |
|
swap(env); |
1084 |
|
if(env->err) return; |
1085 |
|
|
1086 |
|
toss(env); |
1087 |
|
if(env->err) return; |
1088 |
|
|
1089 |
|
eval(env); |
1090 |
|
} |