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string::token::shell(3tcl) Text and string utilities string::token::shell(3tcl) 





NAME


string::token::shell - Parsing of shell command line






SYNOPSIS


package require Tcl 8.5 9


package require string::token::shell ?1.3?


package require string::token ?1?


package require fileutil


::string token shell ?-indices? ?-partial?
    ?--? string










DESCRIPTION


This package provides a command which parses a line of text using
    basic sh-syntax into a list of words.


The complete set of procedures is described below.



  
::string token shell ?-indices? ?-partial? ?--?
    string

  
This command parses the input string under the assumption of it
      following basic sh-syntax. The result of the command is a list of
      words in the string. An error is thrown if the input does not
      follow the allowed syntax. The behaviour can be modified by specifying any
      of the two options -indices and -partial.







  
--

  
When specified option parsing stops at this point. This option is needed
      if the input string may start with dash. In other words, this is
      pretty much required if string is user input.

  

  
When specified the output is not a list of words, but a list of 4-tuples
      describing the words. Each tuple contains the type of the word, its start-
      and end-indices in the input, and the actual text of the word.
    
Note that the length of the word as given by the indices can
        differ from the length of the word found in the last element of the
        tuple. The indices describe the words extent in the input, including
        delimiters, intra-word quoting, etc. whereas for the actual text of the
        word delimiters are stripped, intra-word quoting decoded, etc.

    
The possible token types are

  







  

  
Plain word, not quoted.

  

  
Word is delimited by double-quotes.

  

  
Word is delimited by single-quotes.

  

  

  

  
Like the previous types, but the word has no closing quote, i.e. is
      incomplete. These token types can occur if and only if the option
      -partial was specified, and only for the last word of the result.
      If the option -partial was not specified such incomplete words
      cause the command to thrown an error instead.







  

  
When specified the parser will accept an incomplete quoted word (i.e.
      without closing quote) at the end of the line as valid instead of throwing
      an error.






The basic shell syntax accepted here are unquoted, single- and
    double-quoted words, separated by whitespace. Leading and trailing
    whitespace are possible too, and stripped. Shell variables in their various
    forms are not recognized, nor are sub-shells. As for the recognized
    forms of words, see below for the detailed specification.





  

  
A single-quoted word begins with a single-quote character, i.e. '
      (ASCII 39) followed by zero or more unicode characters not a single-quote,
      and then closed by a single-quote.
    
The word must be followed by either the end of the string, or
        whitespace. A word cannot directly follow the word.

  

  

  
A double-quoted word begins with a double-quote character, i.e.
      " (ASCII 34) followed by zero or more unicode characters not a
      double-quote, and then closed by a double-quote.
    
Contrary to single-quoted words a double-quote can be embedded
        into the word, by prefacing, i.e. escaping, i.e. quoting it with a
        backslash character \ (ASCII 92). Similarly a backslash character
        must be quoted with itself to be inserted literally.

  

  

  
Unquoted words are not delimited by quotes and thus cannot contain
      whitespace or single-quote characters. Double-quote and backslash
      characters can be put into unquoted words, by quting them like for
      double-quoted words.

  

  
Whitespace is any unicode space character. This is equivalent to string
      is space, or the regular expression \\s.
    
Whitespace may occur before the first word, or after the last
        word. Whitespace must occur between adjacent words.

  










BUGS, IDEAS, FEEDBACK


This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    textutil of the Tcllib Trackers
    [http://core.tcl.tk/tcllib/reportlist]. Please also report any ideas for
    enhancements you may have for either package and/or documentation.


When proposing code changes, please provide unified diffs,
    i.e the output of diff -u.


Note further that attachments are strongly preferred over
    inlined patches. Attachments can be made by going to the Edit form of
    the ticket immediately after its creation, and then using the left-most
    button in the secondary navigation bar.






KEYWORDS


bash, lexing, parsing, shell, string, tokenization






CATEGORY


Text processing







  

    1.3
    tcllib