From 82b2136a69ce8eddf421bdbb92a4068872e15655 Mon Sep 17 00:00:00 2001
From: Garritt McCune <glmccune@gmail.com>
Date: Fri, 25 Aug 2023 00:21:19 -0500
Subject: [PATCH] Started to work on setting up Symbol value resolution which
 will be based on an abstract syntax tree that can handle undefined values if
 unknown symbols are used in an expression.

---
 includes/symbols_table.h |  9 +++++++++
 src/parser.c             |  8 +++++---
 src/symbols_table.c      | 30 ++++++++++++++++++++++++++++++
 src/token.c              |  2 --
 4 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/includes/symbols_table.h b/includes/symbols_table.h
index 84c353b..65daea6 100644
--- a/includes/symbols_table.h
+++ b/includes/symbols_table.h
@@ -12,11 +12,18 @@
 
 #define SYMBOLSTABLE_DEFAULT_CAPACITY 128
 
+typedef struct __token_node {
+    Token* Token;
+    struct __token_node* Left;
+    struct __token_node* Right;
+} TokenNode;
+
 typedef struct _symbol {
     char* Name;
     int Address;
     int Length;
     Token* Token;
+    TokenNode* ValueExpression;
 } Symbol;
 
 typedef struct {
@@ -26,10 +33,12 @@ typedef struct {
 } SymbolTable;
 
 SymbolTable* CreateSymbolTable(void);
+TokenNode* CreateTokenNode(Token* token);
 int TryGetSymbol(char* name, SymbolTable* table, Symbol** outSymbol);
 Symbol* AddSymbolToTable(char* name, int address, SymbolTable* table);
 void FreeSymbolTable(SymbolTable* table);
 void FreeSymbol(Symbol* symbol);
 int SymbolResolved(Symbol* symbol);
+int TryGetSymbolValue(const Symbol* symbol, const SymbolTable* table, unsigned short** value);
 
 #endif
\ No newline at end of file
diff --git a/src/parser.c b/src/parser.c
index 3179817..a7355de 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -23,7 +23,7 @@ void ExpectPuncuation(TokenPunctuation punctuation, ExpectOptions options);
 void ExpectRegister(void);
 Symbol* ExpectIdentifier(ExpectOptions options, int expectUnresolved);
 void ExpectCharacterClass(Symbol* symbol);
-void ExpectLineEndOrFileEnd(ExpectOptions options);
+Token* ExpectLineEndOrFileEnd(ExpectOptions options);
 
 SymbolTable* SymbolsTable;
 
@@ -489,10 +489,10 @@ void ExpectCharacterClass(Symbol* symbol) {
     ExpectLineEndOrFileEnd(RemoveExpected);
 }
 
-void ExpectLineEndOrFileEnd(ExpectOptions options) {
+Token* ExpectLineEndOrFileEnd(ExpectOptions options) {
     Token* token = PeekToken();
 
-    if (token->EndOfFile) return;
+    if (token->EndOfFile) return token;
 
     if (token->Class != PunctuationClass || token->Value.Punctuation != NewLine) {
         fprintf(stderr, "[Line %d] Syntax error, expected line break.\n", token->LineNumber);
@@ -501,6 +501,8 @@ void ExpectLineEndOrFileEnd(ExpectOptions options) {
 
     if (options & RemoveExpected) RemoveCurrentToken();
     if (options & ForwardParser) AdvanceParser();
+
+    return token;
 }
 
 void PrintSymbols(void) {
diff --git a/src/symbols_table.c b/src/symbols_table.c
index d9ac537..acba3a0 100644
--- a/src/symbols_table.c
+++ b/src/symbols_table.c
@@ -117,4 +117,34 @@ void FreeSymbol(Symbol* symbol) {
     if (!symbol) return;
 
     free(symbol);
+}
+
+int TryGetSymbolValue(const Symbol* symbol, const SymbolTable* table, unsigned short** value) {
+    if (!symbol || !symbol->Token || !table) return 0;
+    if (symbol->Token->Class == CharacterClass) return 0;
+
+    unsigned short acc = 0;
+    Token* current = symbol->Token->Next;
+
+    for(;;) {
+        if (current->Class == PunctuationClass && current->Value.Punctuation == NewLine) break;
+        Token* next = current->Next;
+
+
+    }
+
+    return 1;
+}
+
+TokenNode* CreateTokenNode(Token* token){
+    TokenNode* node = calloc(1, sizeof(TokenNode));
+
+    if (!node) {
+        fprintf(stderr, "Failed to calloc memory for a TokenNode. %s.\n", strerror(errno));
+        return NULL;
+    }
+
+    node->Token = token;
+
+    return node;
 }
\ No newline at end of file
diff --git a/src/token.c b/src/token.c
index c95557b..a6bc85a 100644
--- a/src/token.c
+++ b/src/token.c
@@ -83,6 +83,4 @@ void RemoveToken(int index, TokenList* list) {
     list->size--;
 
     list->content[list->size] = NULL;
-
-    FreeToken(token);
 }
\ No newline at end of file