Native shebang: Difference between revisions

</pre>

=={{header|zkl}}==

This isn't something that is usually done with zkl as the compiler is fast enough (for scripts) to just run the source and let it get compiled and run. But, it can be done.

Since the #! parsing is done by a compiler front end and was designed to be used from the command line, we'll do that by forking zkl to compile the source if it is newer than the binary.

<lang zkl>#!/home/craigd/Bin/zkl

// This file: nativeShebang.zkl

// zkl --#! . -c nativeShebang -o.

// chmod a+x nativeShebang.z*

// ./nativeShebang.zsc

// If this [source] file is newer than the compiled version (or the

// compiled file doesn't exist), compile up a new version

srcName :=__FILE__;

compiledName:=File.splitFileName(srcName)[0,-1].concat() + ".zsc";

if(not File.exists(compiledName) or

File.info(srcName)[2] > File.info(compiledName)[2]){ // compare modifed dates

System.cmd("zkl --#! . -c %s -o. --exit".fmt(srcName));

System.cmd("chmod a+x %s".fmt(compiledName));

}

println("Hello world!");</lang>

{{out}}

<pre>

#run the source in the usual manner to generate a binary

$ zkl nativeShebang.zkl

Compiled Class(nativeShebang) (0.0 seconds, ??? lines/sec)

Wrote Class(nativeShebang) to ./nativeShebang.zsc

Hello world!

#eyeball the binary

$ zkl hexDump nativeShebang.zsc

0: 23 21 2f 68 6f 6d 65 2f | 63 72 61 69 67 64 2f 42 #!/home/craigd/B

16: 69 6e 2f 7a 6b 6c 0a 7a | 6b 44 00 00 28 31 2e 31 in/zkl.zkD..(1.1

32: 00 5a 4b 4c 20 53 65 72 | 69 61 6c 69 7a 65 64 20 .ZKL Serialized

48: 43 6c 61 73 73 00 6e 61 | 74 69 76 65 53 68 65 62 Class.nativeSheb

64: 61 6e 67 00 00 02 00 00 | 34 2b 61 74 74 72 69 62 ang.....4+attrib

80: 75 74 65 73 3a 73 74 61 | 74 69 63 20 63 72 65 61 utes:static crea

96: 74 65 52 65 74 75 72 6e | 73 53 65 6c 66 00 6e 61 teReturnsSelf.na

112: 74 69 76 65 53 68 65 62 | 61 6e 67 00 00 00 01 00 tiveShebang.....

...

#run the binary

$ ./nativeShebang.zsc

Hello world!

#see if update works

$ touch ./nativeShebang.zkl

$ ./nativeShebang.zsc

Compiled Class(nativeShebang) (0.0 seconds, ??? lines/sec)

Wrote Class(nativeShebang) to ./nativeShebang.zsc

Hello world!

#yep, new binary generated