Ben / Nujel

/* Nujel - Copyright (C) 2020-2022 - Benjamin Vincent Schulenburg
 * This project uses the MIT license, a copy should be included under /LICENSE */
#include "closure.h"

#include "../nujel.h"
#include "../allocation/allocator.h"
#include "../allocation/garbage-collection.h"
#include "../allocation/symbol.h"
#include "../printer.h"
#include "../reader.h"
#include "../type/closure.h"
#include "../type/tree.h"
#include "../type/val.h"

#include <ctype.h>
#include <string.h>

lClosure *lClosureNew(lClosure *parent, closureType t){
	lClosure *c = lClosureAlloc();
	c->parent = parent;
	c->type = t;
	if(parent){
		c->caller = parent->caller;
		c->name = parent->name;
	}
	c->rsp = lRootsGet();
	return c;
}

lClosure *lClosureNewFunCall (lClosure *parent, lVal *args, lVal *lambda){
	lClosure *tmpc = lClosureNew(lambda->vClosure, closureCall);
	tmpc->text = lambda->vClosure->text;
	tmpc->name = lambda->vClosure->name;
	tmpc->caller = parent;
	tmpc->ip   = tmpc->text->data;
	for(lVal *n = lambda->vClosure->args; n; n = n->vList.cdr){
		if(n->type == ltPair){
			lVal *car = lCar(n);
			if(car){lDefineClosureSym(tmpc, lGetSymbol(car), lCar(args));}
			args = lCdr(args);
		}else if(n->type == ltSymbol){
			if(n){lDefineClosureSym(tmpc, lGetSymbol(n), args);}
		}else{
			lExceptionThrowValClo("invalid-lambda", "Incorrect type in argument list", lambda, parent);
		}
	}
	return tmpc;
}

/* Define the NFunc LNF in C with all the space separated symbols in SYM */
lVal *lDefineAliased(lClosure *c, lVal *lNF, const char *sym){
	const char *cur = sym;
	if(lNF->type != ltNativeFunc){
		lExceptionThrowValClo(":invalid-alias-definition","Only native functions and special forms can be defined with an alias",lNF, c);
	}

	// Run at most 64 times, just a precaution
	for(int i=0;i<64;i++){
		uint len;
		for(len=0;len < sizeof(lSymbol);len++){ // Find the end of the current token, either space or 0
			if(cur[len] == 0)        {break;}
			if(isspace((u8)cur[len])){break;}
		}
		lSymbol *name = lSymSL(cur,len);
		lDefineClosureSym(c,name,lNF);
		if(lNF->vNFunc->name == NULL){lNF->vNFunc->name = name;}
		for(;len<32;len++){ // Advance to the next non whitespace character
			if(cur[len] == 0)     {return lNF;} // Or return if we reached the final 0 byte
			if(!isspace((u8)cur[len])){break;}
		}
		cur += len;
	}
	fpf(stderr, "Quite the amount of aliases we have there (%s)\n",sym);
	return NULL;
}

/* Return TRUE if C contains a binding for S, storing the value in V */
bool lHasClosureSym(lClosure *c, const lSymbol *s, lVal **v){
	bool found = false;
	while(c != NULL){
		lVal *t = lTreeGet(c->data,s,&found);
		if(found){
			if(v != NULL){
				*v = t;
			}
			return true;
		}
		c = c->parent;
	}
	return false;
}

lVal *lGetClosureSym(lClosure *c, const lSymbol *s){
	for(lClosure *cc = c; cc; cc = cc->parent){
		lVal *ret;
		if(lTreeHas(cc->data,s,&ret)){return ret;}
	}
	lExceptionThrowValClo("unbound-variable","Can't resolve symbol", lValSymS(s), c);
	return NULL;
}

/* Bind the value V to the Symbol S in the closure C, defining it if necessary */
void lDefineClosureSym(lClosure *c, const lSymbol *s, lVal *v){
	c->data = lTreeInsert(c->data,s,v);
}

/* Set the value bound to S in C to V, if it has already been bound */
bool lSetClosureSym(lClosure *c, const lSymbol *s, lVal *v){
	if(c == NULL){return false;}
	bool found = false;
	lTreeSet(c->data,s,v,&found);
	if(found){return true;}
	return lSetClosureSym(c->parent,s,v);
}

/* Turn STR into a symbol, and bind VAL to it within C */
void lDefineVal(lClosure *c, const char *str, lVal *val){
	lDefineClosureSym(c,lSymS(str),val);
}

/* Add a NFunc to closure C, should only be used during root closure creation */
lVal *lAddNativeFunc(lClosure *c, const char *sym, const char *args, const char *doc, lVal *(*func)(lClosure *,lVal *)){
	lVal *v = lValAlloc(ltNativeFunc);
	v->vNFunc = lNFuncAlloc();
	v->vNFunc->fp   = func;
	v->vNFunc->meta = lTreeInsert(NULL, symDocumentation, lValString(doc));
	v->vNFunc->args = lCar(lRead(c, args));
	return lDefineAliased(c,v,sym);
}

/* Create a new Lambda Value */
lVal *lLambdaNew(lClosure *parent, lVal *name, lVal *args, lVal *body){
	const lSymbol *sym = (name && name->type == ltSymbol) ? name->vSymbol : NULL;

	lVal *ret = lValAlloc(ltLambda);
	ret->vClosure       = lClosureNew(parent, closureDefault);
	ret->vClosure->name = sym;
	ret->vClosure->args = args;
	ret->vClosure->text = requireBytecodeArray(parent, body);
	ret->vClosure->ip   = ret->vClosure->text->data;
	return ret;
}

void lClosureSetMeta(lClosure *c, lVal *doc){
	if((doc == NULL) || (doc->type != ltTree)){return;}
	c->meta = (doc->vTree->flags & TREE_IMMUTABLE) ? lTreeDup(doc->vTree) : doc->vTree;
}