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#include <stddef.h> |
#include <stddef.h> |
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/* dlopen, dlsym, dlerror */ |
/* dlopen, dlsym, dlerror */ |
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#include <dlfcn.h> |
#include <dlfcn.h> |
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/* assert */ |
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#include <assert.h> |
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#define HASHTBLSIZE 65536 |
#define HASHTBLSIZE 65536 |
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typedef struct stack_item |
/* First, define some types. */ |
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{ |
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enum {value, string, ref, func, symbol, list} type; |
/* A value of some type */ |
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typedef struct { |
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enum { |
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integer, |
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string, |
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func, /* Function pointer */ |
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symb, |
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list |
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} type; /* Type of stack element */ |
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union { |
union { |
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void* ptr; |
void *ptr; /* Pointer to the content */ |
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int val; |
int val; /* ...or an integer */ |
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} content; |
} content; /* Stores a pointer or an integer */ |
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int refcount; /* Reference counter */ |
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} value; |
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/* A symbol with a name and possible value */ |
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/* (These do not need reference counters, they are kept unique by |
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hashing.) */ |
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typedef struct symbol_struct { |
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char *id; /* Symbol name */ |
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value *val; /* The value (if any) bound to it */ |
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struct symbol_struct *next; /* In case of hashing conflicts, a */ |
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} symbol; /* symbol is a kind of stack item. */ |
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char* id; |
/* A type for a hash table for symbols */ |
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struct stack_item* next; |
typedef symbol *hashtbl[HASHTBLSIZE]; /* Hash table declaration */ |
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} stackitem; |
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/* An item (value) on a stack */ |
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typedef struct stackitem_struct |
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{ |
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value *item; /* The value on the stack */ |
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struct stackitem_struct *next; /* Next item */ |
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} stackitem; |
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typedef stackitem* hashtbl[HASHTBLSIZE]; |
/* An environment; gives access to the stack and a hash table of |
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typedef void (*funcp)(stackitem**); |
defined symbols */ |
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typedef struct { |
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stackitem *head; /* Head of the stack */ |
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hashtbl symbols; /* Hash table of all variable bindings */ |
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int err; /* Error flag */ |
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} environment; |
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/* A type for pointers to external functions */ |
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typedef void (*funcp)(environment *); /* funcp is a pointer to a void |
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function (environment *) */ |
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void init_hashtbl(hashtbl out_hash) |
/* Initialize a newly created environment */ |
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void init_env(environment *env) |
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{ |
{ |
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long i; |
long i; |
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env->err=0; |
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for(i= 0; i<HASHTBLSIZE; i++) |
for(i= 0; i<HASHTBLSIZE; i++) |
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out_hash[i]= NULL; |
env->symbols[i]= NULL; |
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} |
} |
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stackitem** hash(hashtbl in_hashtbl, const char* in_string) |
/* Returns a pointer to a pointer to an element in the hash table. */ |
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symbol **hash(hashtbl in_hashtbl, const char *in_string) |
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{ |
{ |
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long i= 0; |
long i= 0; |
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unsigned long out_hash= 0; |
unsigned long out_hash= 0; |
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char key= 0; |
char key= '\0'; |
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stackitem** position; |
symbol **position; |
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while(1){ |
while(1){ /* Hash in_string */ |
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key= in_string[i++]; |
key= in_string[i++]; |
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if(key=='\0') |
if(key=='\0') |
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break; |
break; |
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position= &(in_hashtbl[out_hash]); |
position= &(in_hashtbl[out_hash]); |
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while(1){ |
while(1){ |
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if(*position==NULL) |
if(*position==NULL) /* If empty */ |
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return position; |
return position; |
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if(strcmp(in_string, (*position)->id)==0) |
if(strcmp(in_string, (*position)->id)==0) /* If match */ |
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return position; |
return position; |
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position= &((*position)->next); |
position= &((*position)->next); /* Try next */ |
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} |
} |
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} |
} |
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/* Generic push function. */ |
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int push(stackitem** stack_head, stackitem* in_item) |
void push(stackitem** stack_head, stackitem* in_item) |
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{ |
{ |
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in_item->next= *stack_head; |
in_item->next= *stack_head; |
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*stack_head= in_item; |
*stack_head= in_item; |
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return 1; |
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} |
} |
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int push_val(stackitem** stack_head, int in_val) |
/* Push a value onto the stack */ |
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void push_val(stackitem **stack_head, value *val) |
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{ |
{ |
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stackitem* new_item= malloc(sizeof(stackitem)); |
stackitem *new_item= malloc(sizeof(stackitem)); |
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new_item->content.val= in_val; |
new_item->item= val; |
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new_item->type= value; |
val->refcount++; |
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push(stack_head, new_item); |
push(stack_head, new_item); |
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return 1; |
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} |
} |
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int push_cstring(stackitem** stack_head, const char* in_string) |
/* Push an integer onto the stack. */ |
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void push_int(stackitem **stack_head, int in_val) |
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{ |
{ |
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stackitem* new_item= malloc(sizeof(stackitem)); |
value *new_value= malloc(sizeof(value)); |
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new_item->content.ptr= malloc(strlen(in_string)+1); |
stackitem *new_item= malloc(sizeof(stackitem)); |
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strcpy(new_item->content.ptr, in_string); |
new_item->item= new_value; |
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new_item->type= string; |
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new_value->content.val= in_val; |
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new_value->type= integer; |
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new_value->refcount=1; |
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push(stack_head, new_item); |
push(stack_head, new_item); |
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return 1; |
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} |
} |
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int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id) |
/* Copy a string onto the stack. */ |
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void push_cstring(stackitem **stack_head, const char *in_string) |
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{ |
{ |
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in_item->id= malloc(strlen(id)+1); |
value *new_value= malloc(sizeof(value)); |
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stackitem *new_item= malloc(sizeof(stackitem)); |
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new_item->item=new_value; |
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new_value->content.ptr= malloc(strlen(in_string)+1); |
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strcpy(new_value->content.ptr, in_string); |
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new_value->type= string; |
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new_value->refcount=1; |
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strcpy(in_item->id, id); |
push(stack_head, new_item); |
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push(hash(in_hashtbl, id), in_item); |
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return 1; |
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} |
} |
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void def_func(hashtbl in_hashtbl, funcp in_func, const char* id) |
/* Push a symbol onto the stack. */ |
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void push_sym(environment *env, const char *in_string) |
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{ |
{ |
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stackitem* temp= malloc(sizeof(stackitem)); |
stackitem *new_item; /* The new stack item */ |
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/* ...which will contain... */ |
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temp->type= func; |
value *new_value; /* A new symbol value */ |
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temp->content.ptr= in_func; |
/* ...which might point to... */ |
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symbol **new_symbol; /* (if needed) A new actual symbol */ |
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mk_hashentry(in_hashtbl, temp, id); |
/* ...which, if possible, will be bound to... */ |
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value *new_fvalue; /* (if needed) A new function value */ |
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/* ...which will point to... */ |
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void *funcptr; /* A function pointer */ |
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static void *handle= NULL; /* Dynamic linker handle */ |
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/* Create a new stack item containing a new value */ |
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new_item= malloc(sizeof(stackitem)); |
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new_value= malloc(sizeof(value)); |
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new_item->item=new_value; |
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/* The new value is a symbol */ |
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new_value->type= symb; |
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new_value->refcount= 1; |
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/* Look up the symbol name in the hash table */ |
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new_symbol= hash(env->symbols, in_string); |
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new_value->content.ptr= *new_symbol; |
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if(*new_symbol==NULL) { /* If symbol was undefined */ |
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/* Create a new symbol */ |
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(*new_symbol)= malloc(sizeof(symbol)); |
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(*new_symbol)->val= NULL; /* undefined value */ |
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(*new_symbol)->next= NULL; |
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(*new_symbol)->id= malloc(strlen(in_string)+1); |
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strcpy((*new_symbol)->id, in_string); |
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/* Intern the new symbol in the hash table */ |
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new_value->content.ptr= *new_symbol; |
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/* Try to load the symbol name as an external function, to see if |
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we should bind the symbol to a new function pointer value */ |
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if(handle==NULL) /* If no handle */ |
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handle= dlopen(NULL, RTLD_LAZY); |
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funcptr= dlsym(handle, in_string); /* Get function pointer */ |
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if(dlerror()==NULL) { /* If a function was found */ |
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new_fvalue= malloc(sizeof(value)); /* Create a new value */ |
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new_fvalue->type=func; /* The new value is a function pointer */ |
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new_fvalue->content.ptr=funcptr; /* Store function pointer */ |
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(*new_symbol)->val= new_fvalue; /* Bind the symbol to the new |
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function value */ |
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new_fvalue->refcount= 1; |
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} |
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} |
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push(&(env->head), new_item); |
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} |
} |
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void def_sym(hashtbl in_hashtbl, const char* id) |
void printerr(const char* in_string) { |
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{ |
fprintf(stderr, "Err: %s\n", in_string); |
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stackitem* temp= malloc(sizeof(stackitem)); |
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temp->type= symbol; |
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mk_hashentry(in_hashtbl, temp, id); |
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} |
} |
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int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string) |
/* Throw away a value */ |
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{ |
void free_val(value *val){ |
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static void* handle= NULL; |
stackitem *item, *temp; |
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void* symbol; |
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val->refcount--; /* Decrease the reference count */ |
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stackitem* new_item= malloc(sizeof(stackitem)); |
if(val->refcount == 0){ |
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new_item->content.ptr= *hash(in_hash, in_string); |
switch (val->type){ /* and free the contents if necessary */ |
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new_item->type= ref; |
case string: |
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free(val->content.ptr); |
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if(new_item->content.ptr==NULL) { |
case list: /* lists needs to be freed recursively */ |
222 |
if(handle==NULL) |
item=val->content.ptr; |
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handle= dlopen(NULL, RTLD_LAZY); |
while(item != NULL) { /* for all stack items */ |
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free_val(item->item); /* free the value */ |
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symbol= dlsym(handle, in_string); |
temp=item->next; /* save next ptr */ |
226 |
if(dlerror()==NULL) |
free(item); /* free the stackitem */ |
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def_func(in_hash, symbol, in_string); |
item=temp; /* go to next stackitem */ |
228 |
else |
} |
229 |
def_sym(in_hash, in_string); |
free(val); /* Free the actual list value */ |
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break; |
231 |
new_item->content.ptr= *hash(in_hash, in_string); |
default: |
232 |
new_item->type= ref; |
break; |
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} |
234 |
} |
} |
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push(stack_head, new_item); |
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return 1; |
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} |
} |
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extern void toss(stackitem** stack_head) |
/* Discard the top element of the stack. */ |
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extern void toss(environment *env) |
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{ |
{ |
240 |
stackitem* temp= *stack_head; |
stackitem *temp= env->head; |
241 |
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242 |
if((*stack_head)==NULL) |
if((env->head)==NULL) { |
243 |
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printerr("Stack empty"); |
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env->err=1; |
245 |
return; |
return; |
246 |
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} |
247 |
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248 |
if((*stack_head)->type==string) |
free_val(env->head->item); /* Free the value */ |
249 |
free((*stack_head)->content.ptr); |
env->head= env->head->next; /* Remove the top stack item */ |
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free(temp); /* Free the old top stack item */ |
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*stack_head= (*stack_head)->next; |
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free(temp); |
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251 |
} |
} |
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/* Print newline. */ |
254 |
extern void nl() |
extern void nl() |
255 |
{ |
{ |
256 |
printf("\n"); |
printf("\n"); |
257 |
} |
} |
258 |
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void print_(stackitem** stack_head) |
/* Prints the top element of the stack. */ |
260 |
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void print_h(stackitem *stack_head) |
261 |
{ |
{ |
262 |
if((*stack_head)==NULL) |
switch(stack_head->item->type) { |
263 |
return; |
case integer: |
264 |
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printf("%d", stack_head->item->content.val); |
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switch((*stack_head)->type) { |
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case value: |
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printf("%d", (*stack_head)->content.val); |
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265 |
break; |
break; |
266 |
case string: |
case string: |
267 |
printf("%s", (char*)(*stack_head)->content.ptr); |
printf("\"%s\"", (char*)stack_head->item->content.ptr); |
268 |
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break; |
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case symb: |
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printf("'%s'", ((symbol *)(stack_head->item->content.ptr))->id); |
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break; |
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case func: |
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printf("#<function %p>", (funcp)(stack_head->item->content.ptr)); |
274 |
break; |
break; |
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case ref: |
case list: |
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printf("%s", ((stackitem*)(*stack_head)->content.ptr)->id); |
printf("#<list %p>", (funcp)(stack_head->item->content.ptr)); |
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break; |
break; |
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case symbol: |
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default: |
default: |
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printf("%p", (*stack_head)->content.ptr); |
printf("#<unknown %p>", (funcp)(stack_head->item->content.ptr)); |
280 |
break; |
break; |
281 |
} |
} |
282 |
} |
} |
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284 |
extern void print(stackitem** stack_head) |
extern void print_(environment *env) { |
285 |
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if(env->head==NULL) { |
286 |
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printerr("Stack empty"); |
287 |
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env->err=1; |
288 |
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return; |
289 |
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} |
290 |
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print_h(env->head); |
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} |
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/* Prints the top element of the stack and then discards it. */ |
294 |
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extern void print(environment *env) |
295 |
{ |
{ |
296 |
print_(stack_head); |
print_(env); |
297 |
toss(stack_head); |
if(env->err) return; |
298 |
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toss(env); |
299 |
} |
} |
300 |
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/* print_stack(stack); */ |
/* Only to be called by function printstack. */ |
302 |
void print_st(stackitem* stack_head, long counter) |
void print_st(stackitem *stack_head, long counter) |
303 |
{ |
{ |
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if(stack_head->next != NULL) |
if(stack_head->next != NULL) |
305 |
print_st(stack_head->next, counter+1); |
print_st(stack_head->next, counter+1); |
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printf("%ld: ", counter); |
printf("%ld: ", counter); |
307 |
print_(&stack_head); |
print_h(stack_head); |
308 |
nl(); |
nl(); |
309 |
} |
} |
310 |
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311 |
extern void printstack(stackitem** stack_head) |
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313 |
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/* Prints the stack. */ |
314 |
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extern void printstack(environment *env) |
315 |
{ |
{ |
316 |
if(*stack_head != NULL) { |
if(env->head == NULL) { |
317 |
print_st(*stack_head, 1); |
printerr("Stack empty"); |
318 |
printf("\n"); |
env->err=1; |
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return; |
320 |
} |
} |
321 |
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print_st(env->head, 1); |
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nl(); |
323 |
} |
} |
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/* Swap the two top elements on the stack. */ |
326 |
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extern void swap(environment *env) |
327 |
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{ |
328 |
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stackitem *temp= env->head; |
329 |
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330 |
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if((env->head)==NULL) { |
331 |
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printerr("Stack empty"); |
332 |
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env->err=1; |
333 |
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return; |
334 |
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} |
335 |
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336 |
extern void eval(stackitem** stack_head) |
if(env->head->next==NULL) { |
337 |
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printerr("Not enough arguments"); |
338 |
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env->err=1; |
339 |
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return; |
340 |
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} |
341 |
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342 |
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env->head= env->head->next; |
343 |
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temp->next= env->head->next; |
344 |
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env->head->next= temp; |
345 |
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} |
346 |
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347 |
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stackitem* copy(stackitem* in_item) |
348 |
{ |
{ |
349 |
funcp in_func; |
stackitem *out_item= malloc(sizeof(stackitem)); |
350 |
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|
351 |
if((*stack_head)==NULL || (*stack_head)->type!=ref) |
memcpy(out_item, in_item, sizeof(stackitem)); |
352 |
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out_item->next= NULL; |
353 |
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354 |
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return out_item; |
355 |
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} |
356 |
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357 |
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/* Recall a value from a symbol, if bound */ |
358 |
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extern void rcl(environment *env) |
359 |
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{ |
360 |
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value *val; |
361 |
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362 |
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if(env->head == NULL) { |
363 |
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printerr("Stack empty"); |
364 |
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env->err=1; |
365 |
return; |
return; |
366 |
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} |
367 |
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368 |
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if(env->head->item->type!=symb) { |
369 |
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printerr("Not a symbol"); |
370 |
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env->err=1; |
371 |
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return; |
372 |
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} |
373 |
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374 |
if(((stackitem*)(*stack_head)->content.ptr)->type==func) { |
val=((symbol *)(env->head->item->content.ptr))->val; |
375 |
in_func= (funcp)((stackitem*)(*stack_head)->content.ptr)->content.ptr; |
if(val == NULL){ |
376 |
toss(stack_head); |
printerr("Unbound variable"); |
377 |
(*in_func)(stack_head); |
env->err=1; |
378 |
return; |
return; |
379 |
} |
} |
380 |
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toss(env); /* toss the symbol */ |
381 |
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if(env->err) return; |
382 |
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push_val(&(env->head), val); /* Return its bound value */ |
383 |
} |
} |
384 |
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385 |
int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line) |
/* If the top element is a symbol, determine if it's bound to a |
386 |
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function value, and if it is, toss the symbol and execute the |
387 |
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function. */ |
388 |
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extern void eval(environment *env) |
389 |
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{ |
390 |
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funcp in_func; |
391 |
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if(env->head==NULL) { |
392 |
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printerr("Stack empty"); |
393 |
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env->err=1; |
394 |
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return; |
395 |
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} |
396 |
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397 |
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/* if it's a symbol */ |
398 |
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if(env->head->item->type==symb) { |
399 |
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400 |
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rcl(env); /* get its contents */ |
401 |
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if(env->err) return; |
402 |
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if(env->head->item->type!=symb){ /* don't recurse symbols */ |
403 |
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eval(env); /* evaluate the value */ |
404 |
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return; |
405 |
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} |
406 |
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} |
407 |
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408 |
|
/* If it's a lone function value, run it */ |
409 |
|
if(env->head->item->type==func) { |
410 |
|
in_func= (funcp)(env->head->item->content.ptr); |
411 |
|
toss(env); |
412 |
|
if(env->err) return; |
413 |
|
(*in_func)(env); |
414 |
|
} |
415 |
|
} |
416 |
|
|
417 |
|
/* Make a list. */ |
418 |
|
extern void pack(environment *env) |
419 |
|
{ |
420 |
|
void* delimiter; |
421 |
|
stackitem *iterator, *temp; |
422 |
|
value *pack; |
423 |
|
|
424 |
|
delimiter= env->head->item->content.ptr; /* Get delimiter */ |
425 |
|
toss(env); |
426 |
|
|
427 |
|
iterator= env->head; |
428 |
|
|
429 |
|
if(iterator==NULL || iterator->item->content.ptr==delimiter) { |
430 |
|
temp= NULL; |
431 |
|
toss(env); |
432 |
|
} else { |
433 |
|
/* Search for first delimiter */ |
434 |
|
while(iterator->next!=NULL |
435 |
|
&& iterator->next->item->content.ptr!=delimiter) |
436 |
|
iterator= iterator->next; |
437 |
|
|
438 |
|
/* Extract list */ |
439 |
|
temp= env->head; |
440 |
|
env->head= iterator->next; |
441 |
|
iterator->next= NULL; |
442 |
|
|
443 |
|
if(env->head!=NULL) |
444 |
|
toss(env); |
445 |
|
} |
446 |
|
|
447 |
|
/* Push list */ |
448 |
|
pack= malloc(sizeof(value)); |
449 |
|
pack->type= list; |
450 |
|
pack->content.ptr= temp; |
451 |
|
pack->refcount= 1; |
452 |
|
|
453 |
|
temp= malloc(sizeof(stackitem)); |
454 |
|
temp->item= pack; |
455 |
|
|
456 |
|
push(&(env->head), temp); |
457 |
|
} |
458 |
|
|
459 |
|
/* Parse input. */ |
460 |
|
int stack_read(environment *env, char *in_line) |
461 |
{ |
{ |
462 |
char *temp, *rest; |
char *temp, *rest; |
463 |
int itemp; |
int itemp; |
464 |
size_t inlength= strlen(in_line)+1; |
size_t inlength= strlen(in_line)+1; |
465 |
int convert= 0; |
int convert= 0; |
466 |
|
static int non_eval_flag= 0; |
467 |
|
|
468 |
temp= malloc(inlength); |
temp= malloc(inlength); |
469 |
rest= malloc(inlength); |
rest= malloc(inlength); |
470 |
|
|
471 |
if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest)) >= 1) |
do { |
472 |
push_cstring(stack_head, temp); |
/* If string */ |
473 |
else if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest)) >= 1) |
if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) { |
474 |
push_val(stack_head, itemp); |
push_cstring(&(env->head), temp); |
475 |
else if((convert= sscanf(in_line, "%[^ ;\n\r]%[^\n\r]", temp, rest)) >= 1) |
break; |
476 |
push_ref(stack_head, in_hash, temp); |
} |
477 |
else if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest)) >= 1) |
/* If integer */ |
478 |
if(*temp==';') |
if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) { |
479 |
eval(stack_head); |
push_int(&(env->head), itemp); |
480 |
|
break; |
481 |
|
} |
482 |
|
/* Escape ';' with '\' */ |
483 |
|
if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) { |
484 |
|
temp[1]= '\0'; |
485 |
|
push_sym(env, temp); |
486 |
|
break; |
487 |
|
} |
488 |
|
/* If symbol */ |
489 |
|
if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) { |
490 |
|
push_sym(env, temp); |
491 |
|
break; |
492 |
|
} |
493 |
|
/* If single char */ |
494 |
|
if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) { |
495 |
|
if(*temp==';') { |
496 |
|
if(!non_eval_flag) { |
497 |
|
eval(env); /* Evaluate top element */ |
498 |
|
break; |
499 |
|
} |
500 |
|
|
501 |
|
push_sym(env, ";"); |
502 |
|
break; |
503 |
|
} |
504 |
|
|
505 |
|
if(*temp==']') { |
506 |
|
push_sym(env, "["); |
507 |
|
pack(env); |
508 |
|
if(non_eval_flag!=0) |
509 |
|
non_eval_flag--; |
510 |
|
break; |
511 |
|
} |
512 |
|
|
513 |
|
if(*temp=='[') { |
514 |
|
push_sym(env, "["); |
515 |
|
non_eval_flag++; |
516 |
|
break; |
517 |
|
} |
518 |
|
} |
519 |
|
} while(0); |
520 |
|
|
521 |
|
|
522 |
free(temp); |
free(temp); |
523 |
|
|
526 |
return 0; |
return 0; |
527 |
} |
} |
528 |
|
|
529 |
stack_read(stack_head, in_hash, rest); |
stack_read(env, rest); |
530 |
|
|
531 |
free(rest); |
free(rest); |
532 |
return 1; |
return 1; |
533 |
} |
} |
534 |
|
|
535 |
extern void pack(stackitem** stack_head) |
/* Relocate elements of the list on the stack. */ |
536 |
|
extern void expand(environment *env) |
537 |
{ |
{ |
538 |
void* delimiter; |
stackitem *temp, *new_head; |
|
stackitem *iterator, *temp, *pack; |
|
539 |
|
|
540 |
if((*stack_head)==NULL) |
/* Is top element a list? */ |
541 |
|
if(env->head==NULL || env->head->item->type!=list) { |
542 |
|
printerr("Stack empty or not a list"); |
543 |
|
env->err=1; |
544 |
return; |
return; |
545 |
|
} |
546 |
|
|
547 |
delimiter= (*stack_head)->content.ptr; |
/* The first list element is the new stack head */ |
548 |
toss(stack_head); |
new_head= temp= env->head->item->content.ptr; |
|
|
|
|
iterator= *stack_head; |
|
549 |
|
|
550 |
while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter) |
env->head->item->refcount++; |
551 |
iterator= iterator->next; |
toss(env); |
552 |
|
|
553 |
temp= *stack_head; |
/* Find the end of the list */ |
554 |
*stack_head= iterator->next; |
while(temp->next!=NULL) |
555 |
iterator->next= NULL; |
temp= temp->next; |
|
|
|
|
if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter) |
|
|
toss(stack_head); |
|
556 |
|
|
557 |
pack= malloc(sizeof(stackitem)); |
/* Connect the tail of the list with the old stack head */ |
558 |
pack->type= list; |
temp->next= env->head; |
559 |
pack->content.ptr= temp; |
env->head= new_head; /* ...and voila! */ |
560 |
|
|
|
push(stack_head, pack); |
|
561 |
} |
} |
562 |
|
|
563 |
extern void expand(stackitem** stack_head) |
/* Compares two elements by reference. */ |
564 |
|
extern void eq(environment *env) |
565 |
{ |
{ |
566 |
stackitem *temp, *new_head; |
void *left, *right; |
567 |
|
int result; |
568 |
|
|
569 |
if((*stack_head)==NULL || (*stack_head)->type!=list) |
if((env->head)==NULL || env->head->next==NULL) { |
570 |
|
printerr("Not enough elements to compare"); |
571 |
|
env->err=1; |
572 |
return; |
return; |
573 |
|
} |
574 |
|
|
575 |
new_head= temp= (*stack_head)->content.ptr; |
left= env->head->item->content.ptr; |
576 |
toss(stack_head); |
swap(env); |
577 |
|
right= env->head->item->content.ptr; |
578 |
while(temp->next!=NULL) |
result= (left==right); |
579 |
temp= temp->next; |
|
580 |
|
toss(env); toss(env); |
581 |
temp->next= *stack_head; |
push_int(&(env->head), result); |
|
*stack_head= new_head; |
|
582 |
} |
} |
583 |
|
|
584 |
extern void swap(stackitem** stack_head) |
/* Negates the top element on the stack. */ |
585 |
|
extern void not(environment *env) |
586 |
{ |
{ |
587 |
stackitem* temp= (*stack_head); |
int val; |
588 |
|
|
589 |
if((*stack_head)==NULL || (*stack_head)->next==NULL) |
if((env->head)==NULL || env->head->item->type!=integer) { |
590 |
|
printerr("Stack empty or element is not a integer"); |
591 |
|
env->err=1; |
592 |
return; |
return; |
593 |
|
} |
594 |
|
|
595 |
*stack_head= (*stack_head)->next; |
val= env->head->item->content.val; |
596 |
temp->next= (*stack_head)->next; |
toss(env); |
597 |
(*stack_head)->next= temp; |
push_int(&(env->head), !val); |
598 |
} |
} |
599 |
|
|
600 |
extern void eq(stackitem** stack_head) |
/* Compares the two top elements on the stack and return 0 if they're the |
601 |
|
same. */ |
602 |
|
extern void neq(environment *env) |
603 |
{ |
{ |
604 |
void *left, *right; |
eq(env); |
605 |
int result; |
not(env); |
|
|
|
|
if((*stack_head)==NULL || (*stack_head)->next==NULL) |
|
|
return; |
|
|
|
|
|
left= (*stack_head)->content.ptr; |
|
|
right= (*stack_head)->next->content.ptr; |
|
|
result= (left==right); |
|
|
|
|
|
toss(stack_head); toss(stack_head); |
|
|
push_val(stack_head, (left==right)); |
|
606 |
} |
} |
607 |
|
|
608 |
extern void not(stackitem** stack_head) |
/* Give a symbol some content. */ |
609 |
|
extern void def(environment *env) |
610 |
{ |
{ |
611 |
int value; |
symbol *sym; |
612 |
|
|
613 |
if((*stack_head)==NULL) |
/* Needs two values on the stack, the top one must be a symbol */ |
614 |
|
if(env->head==NULL || env->head->next==NULL |
615 |
|
|| env->head->item->type!=symb) { |
616 |
|
printerr("Define what?"); |
617 |
|
env->err=1; |
618 |
return; |
return; |
619 |
|
} |
620 |
|
|
621 |
|
/* long names are a pain */ |
622 |
|
sym=env->head->item->content.ptr; |
623 |
|
|
624 |
value= (*stack_head)->content.val; |
/* if the symbol was bound to something else, throw it away */ |
625 |
toss(stack_head); |
if(sym->val != NULL) |
626 |
push_val(stack_head, !value); |
free_val(sym->val); |
627 |
|
|
628 |
|
/* Bind the symbol to the value */ |
629 |
|
sym->val= env->head->next->item; |
630 |
|
sym->val->refcount++; /* Increase the reference counter */ |
631 |
|
|
632 |
|
toss(env); toss(env); |
633 |
|
} |
634 |
|
|
635 |
|
/* Quit stack. */ |
636 |
|
extern void quit(environment *env) |
637 |
|
{ |
638 |
|
exit(EXIT_SUCCESS); |
639 |
} |
} |
640 |
|
|
641 |
extern void neq(stackitem** stack_head) |
/* Clear stack */ |
642 |
|
extern void clear(environment *env) |
643 |
{ |
{ |
644 |
eq(stack_head); |
while(env->head!=NULL) |
645 |
not(stack_head); |
toss(env); |
646 |
} |
} |
647 |
|
|
648 |
extern void quit() |
/* List all defined words */ |
649 |
|
extern void words(environment *env) |
650 |
{ |
{ |
651 |
exit(EXIT_SUCCESS); |
symbol *temp; |
652 |
|
int i; |
653 |
|
|
654 |
|
for(i= 0; i<HASHTBLSIZE; i++) { |
655 |
|
temp= env->symbols[i]; |
656 |
|
while(temp!=NULL) { |
657 |
|
printf("%s\n", temp->id); |
658 |
|
temp= temp->next; |
659 |
|
} |
660 |
|
} |
661 |
} |
} |
662 |
|
|
663 |
|
/* Forgets a symbol (remove it from the hash table) */ |
664 |
|
extern void forget(environment *env) |
665 |
|
{ |
666 |
|
char* sym_id; |
667 |
|
stackitem *stack_head= env->head; |
668 |
|
symbol **hash_entry, *temp; |
669 |
|
|
670 |
|
if(stack_head==NULL || stack_head->item->type!=symb) { |
671 |
|
printerr("Stack empty or not a symbol"); |
672 |
|
return; |
673 |
|
} |
674 |
|
|
675 |
|
sym_id= ((symbol*)(stack_head->item->content.ptr))->id; |
676 |
|
toss(env); |
677 |
|
|
678 |
|
hash_entry= hash(env->symbols, sym_id); |
679 |
|
temp= *hash_entry; |
680 |
|
*hash_entry= (*hash_entry)->next; |
681 |
|
|
682 |
|
if(temp->val!=NULL) { |
683 |
|
free_val(temp->val); |
684 |
|
} |
685 |
|
free(temp->id); |
686 |
|
free(temp); |
687 |
|
} |
688 |
|
|
689 |
int main() |
int main() |
690 |
{ |
{ |
691 |
stackitem* s= NULL; |
environment myenv; |
|
hashtbl myhash; |
|
692 |
char in_string[100]; |
char in_string[100]; |
693 |
|
|
694 |
init_hashtbl(myhash); |
init_env(&myenv); |
695 |
|
|
696 |
printf("okidok\n "); |
printf("okidok\n "); |
697 |
|
|
698 |
while(fgets(in_string, 100, stdin) != NULL) { |
while(fgets(in_string, 100, stdin) != NULL) { |
699 |
stack_read(&s, myhash, in_string); |
stack_read(&myenv, in_string); |
700 |
|
if(myenv.err) { |
701 |
|
printf("(error %d) ", myenv.err); |
702 |
|
myenv.err=0; |
703 |
|
} |
704 |
printf("okidok\n "); |
printf("okidok\n "); |
705 |
} |
} |
706 |
|
|
707 |
exit(EXIT_SUCCESS); |
exit(EXIT_SUCCESS); |
708 |
} |
} |
|
|
|
|
/* Local Variables: */ |
|
|
/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */ |
|
|
/* End: */ |
|