ref: 95ad5c77a146a99179e4f553662a4203d070adfa
parent: 46ffffade19df38147f79afe991d91e3fc3d53e3
author: Matthew Flatt <mflatt@racket-lang.org>
date: Sat Apr 23 08:23:25 CDT 2022
drop `shell-subst` redundant check for non-string
--- a/lib/zuo/shell.zuo
+++ b/lib/zuo/shell.zuo
@@ -72,22 +72,20 @@
(define (shell-subst str config)
(unless (string? str) (arg-error 'shell-subst "string" str))
(unless (hash? config) (arg-error 'shell-subst "hash table" config))
- (and
- str
- (let loop ([i 0])
- (cond
- [(> (+ i 2) (string-length str)) str]
- [(and (= (char "$") (string-ref str i))
- (= (char "{") (string-ref str (+ i 1))))- (let ([end (let loop ([i (+ i 2)])
- (cond
- [(= i (string-length str)) (error "didn't find closer" str)]
- [(= (char "}") (string-ref str i)) i]
- [else (loop (+ i 1))]))])
- (shell-subst (~a (substring str 0 i)
- (let ([key (string->symbol (substring str (+ i 2) end))])
- (or (hash-ref config key #f)
- (error "shell-subst: no substitution found for name" key)))
- (substring str (+ end 1)))
- config))]
- [else (loop (+ i 1))]))))
+ (let loop ([i 0])
+ (cond
+ [(> (+ i 2) (string-length str)) str]
+ [(and (= (char "$") (string-ref str i))
+ (= (char "{") (string-ref str (+ i 1))))+ (let ([end (let loop ([i (+ i 2)])
+ (cond
+ [(= i (string-length str)) (error "didn't find closer" str)]
+ [(= (char "}") (string-ref str i)) i]
+ [else (loop (+ i 1))]))])
+ (shell-subst (~a (substring str 0 i)
+ (let ([key (string->symbol (substring str (+ i 2) end))])
+ (or (hash-ref config key #f)
+ (error "shell-subst: no substitution found for name" key)))
+ (substring str (+ end 1)))
+ config))]
+ [else (loop (+ i 1))])))