LispPad

Lightweight Scheme Development on macOS

LispKit System OS

Library (lispkit system os) currently defines a single procedure system-call for invoking external binaries as a sub-process of the LispKit interpreter. This library is operating system specific and requires careful usage in portable code.

(system-call path args)     [procedure]
(system-call path args env)
(system-call path args env port)
(system-call path args env port input)

Executes the binary at path passing the string representation of the elements of list args as command-line arguments. env is an association list defining environment variables. Both keys and values are strings. The output generated by executing the binary is directed towards port, which is a textual output port. The default for port corresponds to current-output-port, a parameter object defined by library (lispkit port). Providing #f as port will send the output to /dev/null. input is an optional string which can be used to pipe data into the binary as input. The current implementation is not able to handle interactive binaries. system-call returns the result code for executing the binary (0 refers to a regular exit).


> (system-call "/bin/ls" '(-a -l))
total 863816
drwx------@  47 objecthub    1504 Jun  8 10:56 Desktop
drwx------@  96 objecthub    3072 Jun  7 16:39 Documents
drwx------@ 589 objecthub   18848 May 31 16:59 Downloads
drwx------@  41 objecthub    1312 Dec 19 22:51 Google Drive
drwx------@  84 objecthub    2688 Feb 15 18:32 Library
drwx------+  16 objecthub     512 Oct 20  2019 Movies
drwx------+  10 objecthub     320 Oct 20  2019 Music
drwx------+  10 objecthub     320 May 17 18:37 Pictures
drwxr-xr-x+   5 objecthub     160 Nov 23  2016 Public
0
> (system-call "/usr/bin/bc" '(-q) '() (current-output-port) "10*(11+9)/2\n")
100
0