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authorBryan Newbold <bnewbold@robocracy.org>2017-02-20 00:05:29 -0800
committerBryan Newbold <bnewbold@robocracy.org>2017-02-20 00:05:29 -0800
commit8466d8cfa486fb30d1755c4261b781135083787b (patch)
treec8c12c67246f543c3cc4f64d1c07e003cb1d45ae /lineio.scm
parent87b82b5822ca54228cfa6df29be3ad9d4bc47d16 (diff)
downloadslib-8466d8cfa486fb30d1755c4261b781135083787b.tar.gz
slib-8466d8cfa486fb30d1755c4261b781135083787b.zip
Import Upstream version 3a1upstream/3a1
Diffstat (limited to 'lineio.scm')
-rw-r--r--lineio.scm34
1 files changed, 20 insertions, 14 deletions
diff --git a/lineio.scm b/lineio.scm
index 38a7b87..cfffd33 100644
--- a/lineio.scm
+++ b/lineio.scm
@@ -8,7 +8,7 @@
;1. Any copy made of this software must include this copyright notice
;in full.
;
-;2. I have made no warrantee or representation that the operation of
+;2. I have made no warranty or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
@@ -17,6 +17,7 @@
;promotional, or sales literature without prior written consent in
;each case.
+(require-if 'compiling 'filename)
;;@args
;;@args port
@@ -63,20 +64,25 @@
;;Writes @1 followed by a newline to the given @var{port} and returns
;;an unspecified value. The @var{Port} argument may be omitted, in
;;which case it defaults to the value returned by
-;;@code{current-input-port}.@refill
+;;@code{current-input-port}.
(define (write-line str . port)
(apply display str port)
(apply newline port))
-;;@args path
-;;@args path port
-;;Displays the contents of the file named by @1 to @var{port}. The
-;;@var{port} argument may be ommited, in which case it defaults to the
-;;value returned by @code{current-output-port}.
-(define (display-file path . port)
- (set! port (if (null? port) (current-output-port) (car port)))
- (call-with-input-file path
- (lambda (inport)
- (do ((line (read-line inport) (read-line inport)))
- ((eof-object? line))
- (write-line line port)))))
+;;@args command tmp
+;;@args command
+;;@1 must be a string. The string @2, if supplied, is a path to use as
+;;a temporary file. @0 calls @code{system} with @1 as argument,
+;;redirecting stdout to file @2. @0 returns a string containing the
+;;first line of output from @2.
+(define (system->line command . tmp)
+ (require 'filename)
+ (cond ((null? tmp)
+ (call-with-tmpnam
+ (lambda (tmp) (system->line command tmp))))
+ (else
+ (set! tmp (car tmp))
+ (and (zero? (system (string-append command " > " tmp)))
+ (file-exists? tmp)
+ (let ((line (call-with-input-file tmp read-line)))
+ (if (eof-object? line) "" line))))))