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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 20:03:23 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-18 20:03:23 +0000 |
| commit | f316a2ed52195135a35e32d7096e876357c48c69 (patch) | |
| tree | 5f4486b9a5a213a69e66ef574d6bc643a207981c /doc/runblock.html | |
| download | execline-f316a2ed52195135a35e32d7096e876357c48c69.tar.xz | |
initial commit: rc for execline-2.0.0.0
Diffstat (limited to 'doc/runblock.html')
| -rw-r--r-- | doc/runblock.html | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/doc/runblock.html b/doc/runblock.html new file mode 100644 index 0000000..6f5386e --- /dev/null +++ b/doc/runblock.html @@ -0,0 +1,75 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>execline: the runblock program</title> + <meta name="Description" content="execline: the runblock program" /> + <meta name="Keywords" content="execline command runblock" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">execline</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">www.skarnet.org</a> +</p> + +<h1> The <tt>runblock</tt> program </h1> + +<p> +<tt>runblock</tt>'s purpose is to help you write execline commands +in the execline language. It can only be used inside an execline +script. If the script has been given blocks as arguments, <tt>runblock</tt> +allows you to execute one of the blocks individually. +</p> + +<h2> Interface </h2> + +<pre> + runblock [ -P ] [ -n <em>argshift</em> ] [ -r ] <em>n</em> +</pre> + +<ul> + <li> <tt>runblock</tt> skips the first <em>argshift</em> positional +parameters. It does that to allow you to design commands that take simple +arguments <em>and</em> blocks. </li> + <li> Then <tt>runblock</tt> looks for and parses +<a href="el_semicolon.html">blocks</a> in the positional parameters. </li> + <li> If the <tt>-r</tt> option is present: <tt>runblock</tt> skips +<em>n</em> blocks and execs into the remaining arguments. </li> + <li> Else it skips <em>n</em>-1 blocks and execs into the <em>n</em>th +one. </li> + <li> Normally <tt>runblock</tt> <a href="el_pushenv.html#pop">pops</a> +its environment frame before executing. If the <tt>-P</tt> option has +been given, it <em>does not</em> pop. </li> + <li> Of course, if the block structure doesn't match, <tt>runblock</tt> +exits 100 with an error message. </li> +</ul> + +<h2> Example: implementing the <a href="ifelse.html">ifelse</a> command </h2> + +<p> + Suppose that we want to implement the <a href="ifelse.html">ifelse</a> command as +an execline script, using the <a href="ifte.html">ifte</a> command. +<tt>runblock</tt> allows us to do it in a simple way: +</p> + +<pre> + #!/command/execlineb + ifte { runblock 2 } { runblock -r 2 } runblock 1 +</pre> + +<p> + That's it. +</p> + +<h2> Credits </h2> + +<p> + The <tt>runblock</tt> idea, as well as the <tt>ifelse</tt> idea, comes +from <a href="http://code.dogmap.org/">Paul Jarc</a>. +</p> + +</body> +</html> |