From deeb6aa4aa60e22190087a9615447e742c84a19c Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Thu, 16 Feb 2023 19:24:20 -0800
Subject: added scoping and a lot of memory leaks

---
 src/eval.c | 66 +++++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 35 insertions(+), 31 deletions(-)

(limited to 'src/eval.c')

diff --git a/src/eval.c b/src/eval.c
index b1d4e0a..dffd289 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5,70 +5,74 @@
 #include "hashtable.h"
 #include "parse.h"
 
-hashtable_t* ht;
-const int hashtableSize = 1000;
 const int trueVal = 1;
 sym_t trueSym = {LITERAL, INT, (void*)&trueVal, NULL, 0};
 const int falseVal = 0;
 sym_t falseSym = {LITERAL, INT, (void*)&falseVal, NULL, 0};
 
-void init_eval() {
-	ht = init_hashtable(hashtableSize);
-}
 /* TODO: read base hashtable from file to allow modularity
 pair value value? */
-void exec_all(sym_t** symbols, int count) {
-	for (int i = 0; i < count; i++) {
-		/* dispose of result */
-		eval(symbols[i]);
-	}
-}
-sym_t* eval(sym_t* symbol) {
+sym_t* eval(sym_t* symbol, hashtable_t* parentScope) {
 	if (symbol->province == LITERAL) {
 		return(symbol);
 	}
 	else if (symbol->province == KEY_REF) {
-		sym_t* ir = try_eval_internal(symbol);
+		sym_t* returnV = NULL;
+		/* entering new scope, so create a new table */
+		hashtable_t* newScope = init_hashtable(500, parentScope);
+		sym_t* ir = try_eval_internal(symbol, newScope);
 		if (ir != NULL) {
-			return ir;
+			returnV = ir;
 		}
 		else {
 			/* not an internal function, search hashtable for
 			next symbol */
 			/* TODO: scope */
-			pair_t* p = hashtable_get_pair(ht, (char*)symbol->name);
-			if (p != NULL) {
-				return eval((sym_t*)p->value);
+			pair_t p = hashtable_get_pair_recurse(parentScope, (char*)symbol->name);
+			if (p.key != NULL) {
+				returnV = eval((sym_t*)p.value, newScope);
 			}
 			else {
 				printf("no matching pair in hashtable\n");
-				return NULL;
 			}
 		}
+		/* clear new scope, then return */
+		destroy_hashtable(newScope);
+		return returnV;
 	}
 	else {
 		printf("no symbol province\n");
 		return NULL;
 	}
 }
+void exec_all(sym_t** symbols, int count, hashtable_t* symbolScope) {
+	for (int i = 0; i < count; i++) {
+		eval(symbols[i], symbolScope);
+		destroy_sym(symbols[i]);
+	}
+}
 /* internal functions?
 this function has side-effects */
-sym_t* try_eval_internal(sym_t* symbol) {
+sym_t* try_eval_internal(sym_t* symbol, hashtable_t* symbolScope) {
 	unsigned int hash = get_hash((char*)symbol->name);
-	/* TODO: return last arg. that's the function return line */
 	if (hash == get_hash("root")) {
-		/* execute all args as roots */
-		exec_all(symbol->args, symbol->argCount);
-		return &trueSym;
+		/* execute all args as roots except for the last */
+		/* return last arg, that's the function return line */
+		exec_all(symbol->args, symbol->argCount - 1, symbolScope);
+		return eval(symbol->args[symbol->argCount - 1], symbolScope);
+	}
+	else if (hash == get_hash("arg")) {
+		/* get positional arg in current scope */
+		return NULL;
 	}
 	else if (hash == get_hash("store")) {
 		/* TODO: scope */
 		/* first arg is value, remaining args are names */
 		/* TODO: recursion for multiple pairs */
-		char* k = symtos(eval(symbol->args[1]));
+		char* k = symtos(eval(symbol->args[1], symbolScope));
 		sym_t* v = symbol->args[0];
-		pair_t* p = init_pair(k, (void*)v);
-		hashtable_add_pair(ht, p);
+		pair_t p = init_pair(k, (void*)v);
+		hashtable_add_pair(symbolScope->parent, p);
 		return &trueSym;
 	}
 	/* TODO: release()/free() method? */
@@ -76,7 +80,7 @@ sym_t* try_eval_internal(sym_t* symbol) {
 		litType_t type = NO_TYPE;
 		void* lastVal = NULL;
 		for (int i  = 0; i < symbol->argCount; i++) {
-			sym_t* v = eval(symbol->args[i]);
+			sym_t* v = eval(symbol->args[i], symbolScope);
 			/* initialize */
 			if (type == NO_TYPE) {
 				type = v->litType;
@@ -100,20 +104,20 @@ sym_t* try_eval_internal(sym_t* symbol) {
 		return &trueSym;
 	}
 	else if (hash == get_hash("if")) {
-		sym_t* v = eval(symbol->args[0]);
+		sym_t* v = eval(symbol->args[0], symbolScope);
 		if (symtoi(v) != 0) {
-			exec_all(symbol->args + 1, symbol->argCount - 1);
+			exec_all(symbol->args + 1, symbol->argCount - 1, symbolScope);
 			return &trueSym;
 		}
 		return &falseSym;
 	}
 	else if (hash == get_hash("not")) {
-		sym_t* v = eval(symbol->args[0]);
+		sym_t* v = eval(symbol->args[0], symbolScope);
 		int b = symtoi(v);
 		return b ? &falseSym : &trueSym;
 	}
 	else if (hash == get_hash("print")) {
-		sym_t* v = eval(symbol->args[0]);
+		sym_t* v = eval(symbol->args[0], symbolScope);
 		switch (v->litType) {
 			case NO_TYPE:
 				break;
-- 
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