From 9235c6eaccd6ec3ead1fe848a1e63ff0dbb13eb0 Mon Sep 17 00:00:00 2001
From: Chris Pressey <cpressey@catseye.tc>
Date: Sun, 18 Oct 2015 18:54:28 +0100
Subject: [PATCH] Support line comments.

---
 HISTORY.markdown           |  1 +
 README.markdown            |  2 --
 eg/screen2.60p             |  8 ++++++--
 src/sixtypical/parser.py   |  2 ++
 tests/SixtyPical Syntax.md | 10 ++++++++++
 5 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/HISTORY.markdown b/HISTORY.markdown
index d364a1c..2ab97be 100644
--- a/HISTORY.markdown
+++ b/HISTORY.markdown
@@ -6,6 +6,7 @@ History of SixtyPical
 
 *   Added `byte table` type locations and indexed addressing (`+ x`, `+ y`).
 *   Integer literals may be given in hexadecimal.
+*   Line comments may be included in source code by prefixing them with `//`.
 
 0.4
 ---
diff --git a/README.markdown b/README.markdown
index 2662c15..17ec850 100644
--- a/README.markdown
+++ b/README.markdown
@@ -33,8 +33,6 @@ TODO
 
 For 0.5:
 
-*   source code comments.
-
 For 0.6:
 
 *   `interrupt` routines.
diff --git a/eg/screen2.60p b/eg/screen2.60p
index 221263b..eb45824 100644
--- a/eg/screen2.60p
+++ b/eg/screen2.60p
@@ -1,12 +1,16 @@
+// Displays 256 hearts at the top of the Commodore 64's screen.
+
+// Define where the screen starts in memory:
 byte table screen @ 1024
 
 routine main
+  // These are the values that will be written to by this routine:
   trashes a, x, z, n, screen
 {
     ld x, 0
-    ld a, 83
+    ld a, 83    // 83 = screen code for heart
     repeat {
         st a, screen + x
         inc x
-    } until z
+    } until z   // this flag will be set when x wraps around from 255 to 0
 }
diff --git a/src/sixtypical/parser.py b/src/sixtypical/parser.py
index ee3aa2b..5361484 100644
--- a/src/sixtypical/parser.py
+++ b/src/sixtypical/parser.py
@@ -29,6 +29,8 @@ class Scanner(object):
 
     def scan(self):
         self.scan_pattern(r'[ \t\n\r]*', 'whitespace')
+        while self.scan_pattern(r'\/\/.*?[\n\r]', 'comment'):
+            self.scan_pattern(r'[ \t\n\r]*', 'whitespace')
         if not self.text:
             self.token = None
             self.type = 'EOF'
diff --git a/tests/SixtyPical Syntax.md b/tests/SixtyPical Syntax.md
index 6f8da22..7931771 100644
--- a/tests/SixtyPical Syntax.md	
+++ b/tests/SixtyPical Syntax.md	
@@ -19,6 +19,16 @@ Rudimentary program.
     | }
     = ok
 
+Program with comments.
+
+    | // Welcome to my program.
+    | 
+    | routine main {
+    |     ld a, 0
+    |     add a, 1    // We are adding the thing.
+    | }
+    = ok
+
 Hex literals.
 
     | routine main {