--- stack/stack.c	2002/02/06 21:26:46	1.42
+++ stack/stack.c	2002/02/08 13:01:16	1.63
@@ -1,13 +1,13 @@
-/* printf */
+/* printf, sscanf, fgets, fprintf */
 #include <stdio.h>
-/* EXIT_SUCCESS */
+/* exit, EXIT_SUCCESS, malloc, free */
 #include <stdlib.h>
 /* NULL */
 #include <stddef.h>
 /* dlopen, dlsym, dlerror */
 #include <dlfcn.h>
-/* assert */
-#include <assert.h>
+/* strcmp, strcpy, strlen, strcat, strdup */
+#include <string.h>
 
 #define HASHTBLSIZE 65536
 
@@ -48,6 +48,7 @@
 typedef struct stackitem_struct
 {
   value *item;			/* The value on the stack */
+				/* (This is never NULL) */
   struct stackitem_struct *next; /* Next item */
 } stackitem;
 
@@ -57,6 +58,7 @@
   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 */
@@ -66,18 +68,67 @@
 /* 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; i<HASHTBLSIZE; i++)
     env->symbols[i]= NULL;
 }
 
+void printerr(const char* in_string) {
+  fprintf(stderr, "Err: %s\n", in_string);
+}
+
+/* Throw away a value */
+void free_val(value *val){
+  stackitem *item, *temp;
+
+  val->refcount--;		/* Decrease the reference count */
+  if(val->refcount == 0){
+    switch (val->type){		/* and free the contents if necessary */
+    case string:
+      free(val->content.ptr);
+      break;
+    case list:			/* lists needs to be freed recursively */
+      item=val->content.ptr;
+      while(item != NULL) {	/* for all stack items */
+	free_val(item->item);	/* free the value */
+	temp=item->next;	/* save next ptr */
+	free(item);		/* free the stackitem */
+	item=temp;		/* go to next stackitem */
+      }
+      free(val);		/* Free the actual list value */
+      break;
+    case integer:
+    case func:
+    case symb:
+      break;
+    }
+  }
+}
+
+/* Discard the top element of the stack. */
+extern void toss(environment *env)
+{
+  stackitem *temp= env->head;
+
+  if((env->head)==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+  
+  free_val(env->head->item);	/* Free the value */
+  env->head= env->head->next;	/* Remove the top stack item */
+  free(temp);			/* Free the old top stack item */
+}
+
 /* 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;
   
@@ -147,6 +198,55 @@
   push(stack_head, new_item);
 }
 
+/* Mangle a symbol name to a valid C identifier name */
+char *mangle_str(const char *old_string){
+  char validchars[]
+    ="0123456789abcdef";
+  char *new_string, *current;
+
+  new_string=malloc((strlen(old_string)*2)+4);
+  strcpy(new_string, "sx_");	/* Stack eXternal */
+  current=new_string+3;
+  while(old_string[0] != '\0'){
+    current[0]=validchars[(unsigned char)(old_string[0])/16];
+    current[1]=validchars[(unsigned char)(old_string[0])%16];
+    current+=2;
+    old_string++;
+  }
+  current[0]='\0';
+
+  return new_string;		/* The caller must free() it */
+}
+
+extern void mangle(environment *env){
+  value *new_value;
+  char *new_string;
+
+  if((env->head)==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+
+  if(env->head->item->type!=string) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+
+  new_string= mangle_str((const char *)(env->head->item->content.ptr));
+
+  toss(env);
+  if(env->err) return;
+
+  new_value= malloc(sizeof(value));
+  new_value->content.ptr= new_string;
+  new_value->type= string;
+  new_value->refcount=1;
+
+  push_val(&(env->head), new_value);
+}
+
 /* Push a symbol onto the stack. */
 void push_sym(environment *env, const char *in_string)
 {
@@ -161,6 +261,8 @@
   void *funcptr;		/* A function pointer */
 
   static void *handle= NULL;	/* Dynamic linker handle */
+  const char *dlerr;		/* Dynamic linker error */
+  char *mangled;		/* Mangled function name */
 
   /* Create a new stack item containing a new value */
   new_item= malloc(sizeof(stackitem));
@@ -193,7 +295,14 @@
       handle= dlopen(NULL, RTLD_LAZY);
 
     funcptr= dlsym(handle, in_string); /* Get function pointer */
-    if(dlerror()==NULL) { 	/* If a function was found */
+    dlerr=dlerror();
+    if(dlerr != NULL) {		/* If no function was found */
+      mangled=mangle_str(in_string);
+      funcptr= dlsym(handle, mangled); /* try mangling it */
+      free(mangled);
+      dlerr=dlerror();
+    }
+    if(dlerr==NULL) {		/* If a function was found */
       new_fvalue= malloc(sizeof(value)); /* Create a new value */
       new_fvalue->type=func;	/* The new value is a function pointer */
       new_fvalue->content.ptr=funcptr; /* Store function pointer */
@@ -205,52 +314,6 @@
   push(&(env->head), new_item);
 }
 
-void printerr(const char* in_string) {
-  fprintf(stderr, "Err: %s\n", in_string);
-}
-
-/* Throw away a value */
-void free_val(value *val){
-  stackitem *item, *temp;
-
-  val->refcount--;		/* Decrease the reference count */
-  if(val->refcount == 0){
-    switch (val->type){		/* and free the contents if necessary */
-    case string:
-      free(val->content.ptr);
-      break;
-    case list:			/* lists needs to be freed recursively */
-      item=val->content.ptr;
-      while(item != NULL) {	/* for all stack items */
-	free_val(item->item);	/* free the value */
-	temp=item->next;	/* save next ptr */
-	free(item);		/* free the stackitem */
-	item=temp;		/* go to next stackitem */
-      }
-      free(val);		/* Free the actual list value */
-      break;
-    default:
-      break;
-    }
-  }
-}
-
-/* Discard the top element of the stack. */
-extern void toss(environment *env)
-{
-  stackitem *temp= env->head;
-
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-  
-  free_val(env->head->item);	/* Free the value */
-  env->head= env->head->next;	/* Remove the top stack item */
-  free(temp);			/* Free the old top stack item */
-}
-
 /* Print newline. */
 extern void nl()
 {
@@ -284,9 +347,6 @@
   case list:
     push_sym(env, "list");
     break;
-  default:
-    push_sym(env, "unknown");
-    break;
   }
 }    
 
@@ -298,10 +358,10 @@
     printf("%d", stack_head->item->content.val);
     break;
   case string:
-    printf("\"%s\"", (char*)stack_head->item->content.ptr);
+    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("#<function %p>", (funcp)(stack_head->item->content.ptr));
@@ -317,9 +377,6 @@
     }
     printf("]");
     break;
-  default:
-    printf("#<unknown %p>", (stack_head->item->content.ptr));
-    break;
   }
 }
 
@@ -350,8 +407,6 @@
   nl();
 }
 
-
-
 /* Prints the stack. */
 extern void printstack(environment *env)
 {
@@ -367,13 +422,7 @@
 {
   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;
@@ -384,14 +433,21 @@
   env->head->next= temp;
 } 
 
-stackitem* copy(stackitem* in_item)
+/* Rotate the first three elements on the stack. */
+extern void rot(environment *env)
 {
-  stackitem *out_item= malloc(sizeof(stackitem));
-
-  memcpy(out_item, in_item, sizeof(stackitem));
-  out_item->next= NULL;
+  stackitem *temp= env->head;
+  
+  if(env->head==NULL || env->head->next==NULL
+      || env->head->next->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
 
-  return out_item;
+  env->head= env->head->next->next;
+  temp->next->next= env->head->next;
+  env->head->next= temp;
 }
 
 /* Recall a value from a symbol, if bound */
@@ -422,39 +478,87 @@
   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;
+      return eval(env);		/* evaluate the value */
     }
-  }
+    return;
 
-  /* 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);
+    return (*in_func)(env);
+
+    /* 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) {
+      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;
+	if(iterator->next == NULL){
+	  free_val(temp_val);
+	  return eval(env);
+	}
+	eval(env);
+	if(env->err) return;
+      }
+      iterator= iterator->next;
+    }
+    free_val(temp_val);
+    return;
+
+    /* 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);
+    strcpy(temp_string, "[ ");
+    strcpy(temp_string+2, (char*)temp_val->content.ptr);
+    free_val(temp_val);
+    strcat(temp_string, " ]");
+    stack_read(env, temp_string);
+    free(temp_string);
+    return eval(env);
+
+  case integer:
+    return;
   }
 }
 
-/* Reverse a list */
+/* Reverse (flip) a list */
 extern void rev(environment *env){
   stackitem *old_head, *new_head, *item;
 
@@ -531,12 +635,17 @@
   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);
@@ -561,7 +670,7 @@
     /* 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;
 	}
@@ -573,14 +682,14 @@
       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;
       }
     }
@@ -615,6 +724,11 @@
     return;
   }
 
+  rev(env);
+
+  if(env->err)
+    return;
+
   /* The first list element is the new stack head */
   new_head= temp= env->head->item->content.ptr;
 
@@ -800,3 +914,279 @@
   quit(&myenv);
   return EXIT_FAILURE;
 }
+
+/* + */
+extern void sx_2b(environment *env) {
+  int a, b;
+  size_t len;
+  char* new_string;
+  value *a_val, *b_val;
+
+  if((env->head)==NULL || env->head->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+
+  if(env->head->item->type==string
+     && env->head->next->item->type==string) {
+    a_val= env->head->item;
+    b_val= env->head->next->item;
+    a_val->refcount++;
+    b_val->refcount++;
+    toss(env); if(env->err) return;
+    toss(env); if(env->err) return;
+    len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1;
+    new_string= malloc(len);
+    strcpy(new_string, b_val->content.ptr);
+    strcat(new_string, a_val->content.ptr);
+    free_val(a_val); free_val(b_val);
+    push_cstring(&(env->head), new_string);
+    free(new_string);
+    return;
+  }
+  
+  if(env->head->item->type!=integer
+     || env->head->next->item->type!=integer) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+  a=env->head->item->content.val;
+  toss(env);
+  if(env->err) return;
+  if(env->head->item->refcount == 1)
+    env->head->item->content.val += a;
+  else {
+    b=env->head->item->content.val;
+    toss(env);
+    if(env->err) return;
+    push_int(&(env->head), a+b);
+  }
+}
+
+/* - */
+extern void sx_2d(environment *env) {
+  int a, b;
+
+  if((env->head)==NULL || env->head->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+  
+  if(env->head->item->type!=integer
+     || env->head->next->item->type!=integer) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+  a=env->head->item->content.val;
+  toss(env);
+  if(env->err) return;
+  if(env->head->item->refcount == 1)
+    env->head->item->content.val -= a;
+  else {
+    b=env->head->item->content.val;
+    toss(env);
+    if(env->err) return;
+    push_int(&(env->head), b-a);
+  }
+}
+
+/* > */
+extern void sx_3e(environment *env) {
+  int a, b;
+
+  if((env->head)==NULL || env->head->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+  
+  if(env->head->item->type!=integer
+     || env->head->next->item->type!=integer) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+  a=env->head->item->content.val;
+  toss(env);
+  if(env->err) return;
+  if(env->head->item->refcount == 1)
+    env->head->item->content.val = (env->head->item->content.val > a);
+  else {
+    b=env->head->item->content.val;
+    toss(env);
+    if(env->err) return;
+    push_int(&(env->head), b>a);
+  }
+}
+
+/* Return copy of a value */
+value *copy_val(value *old_value){
+  stackitem *old_item, *new_item, *prev_item;
+
+  value *new_value=malloc(sizeof(value));
+
+  new_value->type=old_value->type;
+  new_value->refcount=0;	/* This is increased if/when this
+				   value is referenced somewhere, like
+				   in a stack item or a variable */
+  switch(old_value->type){
+  case integer:
+    new_value->content.val=old_value->content.val;
+    break;
+  case string:
+    (char *)(new_value->content.ptr)
+      = strdup((char *)(old_value->content.ptr));
+    break;
+  case func:
+  case symb:
+    new_value->content.ptr=old_value->content.ptr;
+    break;
+  case list:
+    new_value->content.ptr=NULL;
+
+    prev_item=NULL;
+    old_item=(stackitem *)(old_value->content.ptr);
+
+    while(old_item != NULL) {	/* While list is not empty */
+      new_item= malloc(sizeof(stackitem));
+      new_item->item=copy_val(old_item->item); /* recurse */
+      new_item->next=NULL;
+      if(prev_item != NULL)	/* If this wasn't the first item */
+	prev_item->next=new_item; /* point the previous item to the
+                                     new item */
+      else
+	new_value->content.ptr=new_item;
+      old_item=old_item->next;
+      prev_item=new_item;
+    }	  
+    break;
+  }
+  return new_value;
+}
+
+/* duplicates an item on the stack */
+extern void dup(environment *env) {
+  if((env->head)==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+  push_val(&(env->head), copy_val(env->head->item));
+}
+
+/* "if", If-Then */
+extern void sx_6966(environment *env) {
+
+  int truth;
+
+  if((env->head)==NULL || env->head->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+
+  if(env->head->next->item->type != integer) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+  
+  swap(env);
+  if(env->err) return;
+  
+  truth=env->head->item->content.val;
+
+  toss(env);
+  if(env->err) return;
+
+  if(truth)
+    eval(env);
+  else
+    toss(env);
+}
+
+/* If-Then-Else */
+extern void ifelse(environment *env) {
+
+  int truth;
+
+  if((env->head)==NULL || env->head->next==NULL
+     || env->head->next->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+
+  if(env->head->next->next->item->type != integer) {
+    printerr("Bad Argument Type");
+    env->err=2;
+    return;
+  }
+  
+  rot(env);
+  if(env->err) return;
+  
+  truth=env->head->item->content.val;
+
+  toss(env);
+  if(env->err) return;
+
+  if(!truth)
+    swap(env);
+  if(env->err) return;
+
+  toss(env);
+  if(env->err) return;
+
+  eval(env);
+}
+
+/* while */
+extern void sx_7768696c65(environment *env) {
+
+  int truth;
+  value *loop, *test;
+
+  if((env->head)==NULL || env->head->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+
+  loop= env->head->item;
+  loop->refcount++;
+  toss(env); if(env->err) return;
+
+  test= env->head->item;
+  test->refcount++;
+  toss(env); if(env->err) return;
+
+  do {
+    push_val(&(env->head), test);
+    eval(env);
+    
+    if(env->head->item->type != integer) {
+      printerr("Bad Argument Type");
+      env->err=2;
+      return;
+    }
+    
+    truth= env->head->item->content.val;
+    toss(env); if(env->err) return;
+    
+    if(truth) {
+      push_val(&(env->head), loop);
+      eval(env);
+    } else {
+      toss(env);
+    }
+  
+  } while(truth);
+
+  free_val(test);
+  free_val(loop);
+}