DESCRIPTION

This document describes the form of a parse tree as used between the various Zoidberg objects.

Example

 # Commandline input:
 
 $ ls -al | perl{ while (<STDIN>) { print $_ }  }abc && echo done
 
 # Would be parsed to:
 
 [ 
	[qw/SH ls -al/],
	[ [qw/PERL abc/], q{ while (<STDIN>) { print $_ } } ],
	'AND',
	[qw/SH echo done/]
 ]
 
 
 
 # Commandline input:
 
 $ cd .. && ls -al ; cp dus ~/tmp/ &
 
 # Would be parsed to:
 
 [
	[qw/CMD cd ../],
	'AND',
	[qw/SH ls -al/],
	'EOS',	# End Of Statement
	[qw{SH cp dus ~/tmp/}],
	'BGS'	# BackGround Statement
 ]
  
 # FIXME an example with redirections

Basics

A parse tree is an array consisting of blocks and tokens. A block can be any kind of code and is stored in a nested array. Blocks directly following each other are supposted to be a pipeline. A token is a delimiter between blocks.

The first field of a block contains information about the block, all other field in a block make up the content. The most important information about a block is the context, which tells the parser how to execute the block. This first field can be:

a scalar       ==> it is the context name
a nested hash  ==> the key 'context' contains the context name

You are free to store all kinds of specific information in this first field, but some key names are reserved.

FIXME reserved meta fields