From c55a3434dec7751b8252ff7d9ee45e28e72d0360 Mon Sep 17 00:00:00 2001
From: Garritt McCune <glmccune@gmail.com>
Date: Tue, 15 Feb 2022 16:32:35 +0000
Subject: [PATCH] Implemented identifier detection but keywords in the
 programming language aren't detected yet.

---
 scanner.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/scanner.c b/scanner.c
index 4e88100..5b2c0e4 100644
--- a/scanner.c
+++ b/scanner.c
@@ -21,6 +21,8 @@ char Peek(void);
 char PeekNext(void);
 void ParseString(TokenList *);
 void ParseNumber(TokenList *);
+void ParseIdentifier(TokenList *);
+int IsAlpha(char c);
 
 TokenList* ScanTokens(const char* source) {
     if (!source) return NULL;
@@ -181,6 +183,9 @@ void ScanToken(TokenList* tokens) {
         if (isdigit(*c)) {
             ParseNumber(tokens);
             break;
+        } else if (IsAlpha(*c)) {
+            ParseIdentifier(tokens);
+            break;
         }
 
         fprintf(stderr, "Unexcpedted character %c\n", *c);
@@ -245,4 +250,16 @@ char PeekNext() {
     if (current + 1 >= length) return '\0';
 
     return source_code[current + 1];
+}
+
+void ParseIdentifier(TokenList * list) {
+    while(IsAlpha(Peek())) Advance();
+
+    AddTokenToList(Identifier, &source_code[start], current - start, list);
+}
+
+int IsAlpha(char c) {
+    return  (c >= 'a' && c <= 'z') ||
+            (c >= 'A' && c <= 'Z') ||
+            (c == '_');
 }
\ No newline at end of file