commit c870538f2526550a99557fbfbdf52eb9d1b40cf6 (patch)
parent 3416bea9d1d42da2b4a394a165f58f00c23b2531
Author: Alex Karle <alex@alexkarle.com>
Date: Sun, 2 Oct 2022 15:44:03 -0400
cleanup: Add tok-1 helper and use ? predicate functions
Diffstat:
| M | scanner.scm | | | 52 | ++++++++++++++++++++++++++++------------------------ |
1 file changed, 28 insertions(+), 24 deletions(-)
diff --git a/scanner.scm b/scanner.scm
@@ -13,10 +13,10 @@
(literal ,literal)
(line ,line)))
- (define (is-digit c)
+ (define (digit? c)
(and c (char<=? #\0 c) (char>=? #\9 c)))
- (define (is-alpha c)
+ (define (alpha? c)
(and c
(or
(eq? c #\_)
@@ -44,8 +44,8 @@
- (define (is-alnum c)
- (and c (or (is-alpha c) (is-digit c))))
+ (define (alnum? c)
+ (and c (or (alpha? c) (digit? c))))
(define (scan src fname)
(define (peek i)
@@ -70,6 +70,10 @@
(else (make-token type text #f line)))))
(cons tok (get-tokens (add1 i2) (add1 i2) line #f)))))
+ (define (tok-1 type)
+ ; helper for length 1 tokens at current position
+ (tok type s s))
+
(define (next l2)
; Helper to iterate while keeping state
(get-tokens s (add1 i) l2 in))
@@ -89,41 +93,41 @@
(else (next line))))
((eq? in 'number)
(cond
- ((is-digit c) (next line))
+ ((digit? c) (next line))
((eq? #\. c) (get-tokens s (add1 i) line 'decimal))
(else (tok 'NUMBER s (sub1 i)))))
((eq? in 'decimal)
(cond
- ((is-digit c) (next line))
+ ((digit? c) (next line))
(else (tok 'NUMBER s (sub1 i)))))
((eq? in 'alpha)
(cond
- ((is-alnum c) (next line))
+ ((alnum? c) (next line))
(else (tok 'IDENTIFIER s (sub1 i)))))
- ((eq? in '=) (if (eq? #\= c) (tok 'EQUAL_EQUAL s i) (tok 'EQUAL s s)))
- ((eq? in '>) (if (eq? #\> c) (tok 'GREATER_EQUAL s i) (tok 'GREATER s s)))
- ((eq? in '<) (if (eq? #\< c) (tok 'LESS_EQUAL s i) (tok 'LESS s s)))
- ((eq? in '!) (if (eq? #\= c) (tok 'BANG_EQUAL s i) (tok 'BANG s s)))
- ((eq? in '/) (if (eq? #\/ c) (get-tokens s (add1 i) line 'comment) (tok 'SLASH s s)))
+ ((eq? in '=) (if (eq? #\= c) (tok 'EQUAL_EQUAL s i) (tok-1 'EQUAL)))
+ ((eq? in '>) (if (eq? #\> c) (tok 'GREATER_EQUAL s i) (tok-1 'GREATER)))
+ ((eq? in '<) (if (eq? #\< c) (tok 'LESS_EQUAL s i) (tok-1 'LESS)))
+ ((eq? in '!) (if (eq? #\= c) (tok 'BANG_EQUAL s i) (tok-1 'BANG)))
+ ((eq? in '/) (if (eq? #\/ c) (get-tokens s (add1 i) line 'comment) (tok-1 'SLASH)))
(else (cond
- ((eq? #\( c) (tok 'LEFT_PAREN s s))
- ((eq? #\) c) (tok 'RIGHT_PAREN s s))
- ((eq? #\{ c) (tok 'LEFT_BRACE s s))
- ((eq? #\} c) (tok 'RIGHT_BRACE s s))
- ((eq? #\, c) (tok 'COMMA s s))
- ((eq? #\. c) (tok 'DOT s s))
- ((eq? #\- c) (tok 'MINUS s s))
- ((eq? #\+ c) (tok 'PLUS s s))
- ((eq? #\; c) (tok 'SEMICOLON s s))
- ((eq? #\* c) (tok 'STAR s s))
+ ((eq? #\( c) (tok-1 'LEFT_PAREN))
+ ((eq? #\) c) (tok-1 'RIGHT_PAREN))
+ ((eq? #\{ c) (tok-1 'LEFT_BRACE))
+ ((eq? #\} c) (tok-1 'RIGHT_BRACE))
+ ((eq? #\, c) (tok-1 'COMMA))
+ ((eq? #\. c) (tok-1 'DOT))
+ ((eq? #\- c) (tok-1 'MINUS))
+ ((eq? #\+ c) (tok-1 'PLUS))
+ ((eq? #\; c) (tok-1 'SEMICOLON))
+ ((eq? #\* c) (tok-1 'STAR))
((eq? #\! c) (get-tokens s (add1 i) line '!))
((eq? #\= c) (get-tokens s (add1 i) line '=))
((eq? #\< c) (get-tokens s (add1 i) line '<))
((eq? #\> c) (get-tokens s (add1 i) line '>))
((eq? #\/ c) (get-tokens s (add1 i) line '/))
((eq? #\" c) (get-tokens s (add1 i) line 'string))
- ((is-digit c) (get-tokens s (add1 i) line 'number))
- ((is-alpha c) (get-tokens s (add1 i) line 'alpha))
+ ((digit? c) (get-tokens s (add1 i) line 'number))
+ ((alpha? c) (get-tokens s (add1 i) line 'alpha))
((eq? #\space c) (get-tokens (add1 i) (add1 i) line #f))
((eq? #\tab c) (get-tokens (add1 i) (add1 i) line #f))
((eq? #\newline c) (get-tokens (add1 i) (add1 i) (add1 line) #f))
