Created the list structure for the tokens to be stored and some helper functions.

scanner.c

@@ -1,4 +1,6 @@
 #include "scanner.h"
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 const char* source_code;
@@ -11,14 +13,15 @@ int line = 1;
 char Advance(void);
 int IsAtend(void);
 void ScanToken(void);
+TokenList* CreateList(void);
 
-void ScanTokens(const char* source) {
+TokenList* ScanTokens(const char* source) {
-    if (!source) return;
+    if (!source) return NULL;
     
     source_code = source;
     length = strlen(source);
 
-    if (length == 0) return;
+    if (length == 0) return NULL;
 
     while(!IsAtend()) {
         start = current;
@@ -28,6 +31,70 @@ void ScanTokens(const char* source) {
     //Add EOF token and return list once that's set up.
 }
 
+TokenList* CreateList() {
+    TokenList* list = calloc(1, sizeof(TokenList));
+
+    if (!list) {
+        fprintf(stderr, "Failed to calloc TokenList.\n");
+        return NULL;
+    }
+
+    list->tokens = calloc(DEFAULT_TOKENLIST_SIZE, sizeof(Token*));
+
+    if (!list->tokens) {
+        free(list);
+        fprintf(stderr, "Failed to calloc tokens.\n");
+        return NULL;
+    }
+
+    list->capacity = DEFAULT_TOKENLIST_SIZE;
+    list->size = 0;
+
+    return list;
+}
+
+void DestroyTokenList(TokenList* list) {
+    if (!list) return;
+
+    for(int i = 0; i < list->size; i++) {
+        free(list->tokens[i]->lexeme);
+        free(list->tokens[i]);
+    }
+
+    free(list->tokens);
+    free(list);
+}
+
+int AddTokenToList(TokenType type, char* lexeme, TokenList* tokens) {
+    if (!tokens) return 0;
+    Token* token = calloc(1, sizeof(Token));
+
+    if (!token) {
+        fprintf(stderr, "Failed to calloc memory for new Token.\n");
+        return 0;
+    }
+
+    token->lexeme = lexeme;
+    token->type = type;
+
+    if ((tokens->size + 1) > tokens->capacity) {
+        void* new_ptr = realloc(tokens->tokens, sizeof(Token*) * tokens->capacity * 2);//calloc(tokens->capacity * 2, sizeof(Token*));
+
+        if (!new_ptr) {
+            fprintf(stderr, "Failed to realloc TokenList to size %d.\n", tokens->capacity * 2);
+            return 0;
+        }
+
+        tokens->tokens = new_ptr;
+        tokens->capacity = tokens->capacity * 2;
+    }
+
+    tokens->tokens[tokens->size] = token;
+    tokens->size++;
+
+    return 1;
+}
+
 void ScanToken() {
     char c = Advance();
 

scanner.h

@@ -1,6 +1,8 @@
 #ifndef SCANNER_H
 #define SCANNER_H
 
+#define DEFAULT_TOKENLIST_SIZE 32
+
 typedef enum {
     //Single-character tokens
     LParen, RParen,
@@ -27,6 +29,19 @@ typedef enum {
     EndOF
 } TokenType;
 
-void ScanTokens(const char*);
+typedef struct {
+    TokenType type;
+    char* lexeme;
+    int line;
+} Token;
+
+typedef struct {
+    Token** tokens;
+    int capacity;
+    int size;
+} TokenList;
+
+TokenList* ScanTokens(const char*);
+void DestroyTokenList(TokenList*);
 
 #endif