--- stack/stack.c 2002/02/06 11:15:05 1.38 +++ stack/stack.c 2002/02/07 04:11:10 1.47 @@ -8,6 +8,8 @@ #include /* assert */ #include +/* strcat */ +#include #define HASHTBLSIZE 65536 @@ -57,6 +59,7 @@ stackitem *head; /* Head of the stack */ hashtbl symbols; /* Hash table of all variable bindings */ int err; /* Error flag */ + int non_eval_flag; } environment; /* A type for pointers to external functions */ @@ -66,9 +69,10 @@ /* Initialize a newly created environment */ void init_env(environment *env) { - long i; + int i; - env->err=0; + env->err= 0; + env->non_eval_flag= 0; for(i= 0; isymbols[i]= NULL; } @@ -76,8 +80,8 @@ /* Returns a pointer to a pointer to an element in the hash table. */ symbol **hash(hashtbl in_hashtbl, const char *in_string) { - long i= 0; - unsigned long out_hash= 0; + int i= 0; + unsigned int out_hash= 0; char key= '\0'; symbol **position; @@ -301,7 +305,7 @@ printf("\"%s\"", (char*)stack_head->item->content.ptr); break; case symb: - printf("'%s'", ((symbol *)(stack_head->item->content.ptr))->id); + printf("%s", ((symbol *)(stack_head->item->content.ptr))->id); break; case func: printf("#", (funcp)(stack_head->item->content.ptr)); @@ -315,7 +319,7 @@ printf(" "); stack_head=stack_head->next; } - printf("] "); + printf("]"); break; default: printf("#", (stack_head->item->content.ptr)); @@ -350,8 +354,6 @@ nl(); } - - /* Prints the stack. */ extern void printstack(environment *env) { @@ -367,13 +369,7 @@ { stackitem *temp= env->head; - if((env->head)==NULL) { - printerr("Too Few Arguments"); - env->err=1; - return; - } - - if(env->head->next==NULL) { + if(env->head==NULL || env->head->next==NULL) { printerr("Too Few Arguments"); env->err=1; return; @@ -384,16 +380,6 @@ env->head->next= temp; } -stackitem* copy(stackitem* in_item) -{ - stackitem *out_item= malloc(sizeof(stackitem)); - - memcpy(out_item, in_item, sizeof(stackitem)); - out_item->next= NULL; - - return out_item; -} - /* Recall a value from a symbol, if bound */ extern void rcl(environment *env) { @@ -422,38 +408,112 @@ push_val(&(env->head), val); /* Return its bound value */ } +void stack_read(environment*, char*); + /* If the top element is a symbol, determine if it's bound to a function value, and if it is, toss the symbol and execute the function. */ extern void eval(environment *env) { funcp in_func; + value* temp_val; + stackitem* iterator; + char* temp_string; + if(env->head==NULL) { printerr("Too Few Arguments"); env->err=1; return; } - /* if it's a symbol */ - if(env->head->item->type==symb) { - + switch(env->head->item->type) { + /* if it's a symbol */ + case symb: rcl(env); /* get its contents */ if(env->err) return; if(env->head->item->type!=symb){ /* don't recurse symbols */ eval(env); /* evaluate the value */ return; } - } + break; - /* If it's a lone function value, run it */ - if(env->head->item->type==func) { + /* If it's a lone function value, run it */ + case func: in_func= (funcp)(env->head->item->content.ptr); toss(env); if(env->err) return; (*in_func)(env); + break; + + /* If it's a list */ + case list: + temp_val= env->head->item; + env->head->item->refcount++; + toss(env); + if(env->err) return; + iterator= (stackitem*)temp_val->content.ptr; + while(iterator!=NULL && iterator->item!=NULL) { + push_val(&(env->head), iterator->item); + if(env->head->item->type==symb + && strcmp(";", ((symbol*)(env->head->item->content.ptr))->id)==0) { + toss(env); + if(env->err) return; + eval(env); + if(env->err) return; + } + iterator= iterator->next; + } + free_val(temp_val); + break; + + /* If it's a string */ + case string: + temp_val= env->head->item; + env->head->item->refcount++; + toss(env); + if(env->err) return; + temp_string= malloc(strlen((char*)temp_val->content.ptr)+5); + strcat(temp_string, "[ "); + strcat(temp_string, (char*)temp_val->content.ptr); + strcat(temp_string, " ]"); + stack_read(env, temp_string); + eval(env); + if(env->err) return; + free_val(temp_val); + free(temp_string); + break; + + default: } } +/* Reverse (flip) a list */ +extern void rev(environment *env){ + stackitem *old_head, *new_head, *item; + + if((env->head)==NULL) { + printerr("Too Few Arguments"); + env->err=1; + return; + } + + if(env->head->item->type!=list) { + printerr("Bad Argument Type"); + env->err=2; + return; + } + + old_head=(stackitem *)(env->head->item->content.ptr); + new_head=NULL; + while(old_head != NULL){ + item=old_head; + old_head=old_head->next; + item->next=new_head; + new_head=item; + } + env->head->item->content.ptr=new_head; +} + /* Make a list. */ extern void pack(environment *env) { @@ -494,6 +554,7 @@ temp->item= pack; push(&(env->head), temp); + rev(env); } /* Parse input. */ @@ -503,12 +564,17 @@ int itemp; size_t inlength= strlen(in_line)+1; int convert= 0; - static int non_eval_flag= 0; temp= malloc(inlength); rest= malloc(inlength); do { + /* If comment */ + if((convert= sscanf(in_line, "#%[^\n\r]", rest))) { + free(temp); free(rest); + return; + } + /* If string */ if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) { push_cstring(&(env->head), temp); @@ -533,7 +599,7 @@ /* If single char */ if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) { if(*temp==';') { - if(!non_eval_flag) { + if(!env->non_eval_flag) { eval(env); /* Evaluate top element */ break; } @@ -545,14 +611,14 @@ if(*temp==']') { push_sym(env, "["); pack(env); - if(non_eval_flag!=0) - non_eval_flag--; + if(env->non_eval_flag) + env->non_eval_flag--; break; } if(*temp=='[') { push_sym(env, "["); - non_eval_flag++; + env->non_eval_flag++; break; } } @@ -587,6 +653,11 @@ return; } + rev(env); + + if(env->err) + return; + /* The first list element is the new stack head */ new_head= temp= env->head->item->content.ptr; @@ -769,6 +840,6 @@ } printf("okidok\n "); } - - exit(EXIT_SUCCESS); + quit(&myenv); + return EXIT_FAILURE; }