From 260a4e771a7abadab0c2bd3f04e3dad27284c2b9 Mon Sep 17 00:00:00 2001
From: Alex Karle <alex@alexkarle.com>
Date: Sun, 2 Oct 2022 02:07:08 -0400
Subject: [PATCH] Fix line numbers in tokens

This is an insteresting example of using a closure to just save some
typing.. but I wonder if it gets redefined every time / is slow?
---
 scanner.scm | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/scanner.scm b/scanner.scm
index 3a368a5..6cc7ded 100644
--- a/scanner.scm
+++ b/scanner.scm
@@ -32,12 +32,12 @@
 
   (define (get-tokens start line)
     ; Gets all tokens after start
-    (define (tok type i len)
-      ; helper to make a token and recurse
-      (cons (make-token type (substring src i (+ i len)) #f line len)
-            (get-tokens (+ i len) line)))
 
     (let loop ((i start) (nline line) (in-comment #f) (in-string #f) (in-number #f) (in-identifier #f))
+      (define (tok type len)
+        ; helper to make a token and recurse -- todo is redefining slow? macro?
+        (cons (make-token type (substring src i (+ i len)) #f nline len)
+              (get-tokens (+ i len) nline)))
       (let ((c (peek i)) (n (peek (add1 i))))
         ;(printf "c: ~A, n: ~A, i: ~A, com: ~A\n" c n i in-comment)
         (if (not c)
@@ -50,21 +50,21 @@
             (in-number #f)
             (in-identifier #f)
             (else (cond
-                    ((eq? #\( c) (tok 'LEFT_PAREN i 1))
-                    ((eq? #\) c) (tok 'RIGHT_PAREN i 1))
-                    ((eq? #\{ c) (tok 'LEFT_BRACE i 1))
-                    ((eq? #\} c) (tok 'RIGHT_BRACE i 1))
-                    ((eq? #\, c) (tok 'COMMA i 1))
-                    ((eq? #\. c) (tok 'DOT i 1))
-                    ((eq? #\- c) (tok 'MINUS i 1))
-                    ((eq? #\+ c) (tok 'PLUS i 1))
-                    ((eq? #\; c) (tok 'SEMICOLON i 1))
-                    ((eq? #\* c) (tok 'STAR i 1))
-                    ((eq? #\! c) (if (eq? #\= n) (tok 'BANG_EQUAL i 2) (tok 'BANG i 1)))
-                    ((eq? #\= c) (if (eq? #\= n) (tok 'EQUAL_EQUAL i 2) (tok 'EQUAL i 1)))
-                    ((eq? #\< c) (if (eq? #\< n) (tok 'LESS_EQUAL i 2) (tok 'LESS i 1)))
-                    ((eq? #\> c) (if (eq? #\> n) (tok 'GREATER_EQUAL i 2) (tok 'GREATER i 1)))
-                    ((eq? #\/ c) (if (eq? #\/ n) (loop (add1 i) nline #t #f #f #f) (tok 'SLASH i 1)))
+                    ((eq? #\( c) (tok 'LEFT_PAREN 1))
+                    ((eq? #\) c) (tok 'RIGHT_PAREN 1))
+                    ((eq? #\{ c) (tok 'LEFT_BRACE 1))
+                    ((eq? #\} c) (tok 'RIGHT_BRACE 1))
+                    ((eq? #\, c) (tok 'COMMA 1))
+                    ((eq? #\. c) (tok 'DOT 1))
+                    ((eq? #\- c) (tok 'MINUS 1))
+                    ((eq? #\+ c) (tok 'PLUS 1))
+                    ((eq? #\; c) (tok 'SEMICOLON 1))
+                    ((eq? #\* c) (tok 'STAR 1))
+                    ((eq? #\! c) (if (eq? #\= n) (tok 'BANG_EQUAL 2) (tok 'BANG 1)))
+                    ((eq? #\= c) (if (eq? #\= n) (tok 'EQUAL_EQUAL 2) (tok 'EQUAL 1)))
+                    ((eq? #\< c) (if (eq? #\< n) (tok 'LESS_EQUAL 2) (tok 'LESS 1)))
+                    ((eq? #\> c) (if (eq? #\> n) (tok 'GREATER_EQUAL 2) (tok 'GREATER 1)))
+                    ((eq? #\/ c) (if (eq? #\/ n) (loop (add1 i) nline #t #f #f #f) (tok 'SLASH 1)))
                     ((eq? #\space c) (loop (add1 i) nline #f #f #f #f))
                     ((eq? #\tab c) (loop (add1 i) nline #f #f #f #f))
                     ((eq? #\newline c) (loop (add1 i) (add1 nline) #f #f #f #f))
--
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