From aa7dff31ffd98e5f3a8e5f485459736527ba24c2 Mon Sep 17 00:00:00 2001
From: Garritt McCune <glmccune@gmail.com>
Date: Tue, 15 Feb 2022 15:59:17 +0000
Subject: [PATCH] Implemented number parsing.

---
 scanner.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/scanner.c b/scanner.c
index d685a0d..4e88100 100644
--- a/scanner.c
+++ b/scanner.c
@@ -2,6 +2,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 
 const char* source_code;
 //Start and Current hold the offsets that index into the string source_code.
@@ -17,7 +18,9 @@ TokenList* CreateList(void);
 int AddTokenToList(TokenType, const char*, int, TokenList*);
 int Match(char);
 char Peek(void);
+char PeekNext(void);
 void ParseString(TokenList *);
+void ParseNumber(TokenList *);
 
 TokenList* ScanTokens(const char* source) {
     if (!source) return NULL;
@@ -175,6 +178,11 @@ void ScanToken(TokenList* tokens) {
         line++;
         break;
     default:
+        if (isdigit(*c)) {
+            ParseNumber(tokens);
+            break;
+        }
+
         fprintf(stderr, "Unexcpedted character %c\n", *c);
         break;
     }
@@ -219,4 +227,22 @@ void ParseString(TokenList *list) {
     AddTokenToList(String, &source_code[start], current - start, list);
 
     Advance(); // The closing ".
+}
+
+void ParseNumber(TokenList* list) {
+    while(isdigit(Peek())) Advance();
+
+    if (Peek() == '.' && isdigit(PeekNext())) {
+        Advance();
+
+        while(isdigit(Peek())) Advance();
+    }
+
+    AddTokenToList(Number, &source_code[start], current - start, list);
+}
+
+char PeekNext() {
+    if (current + 1 >= length) return '\0';
+
+    return source_code[current + 1];
 }
\ No newline at end of file