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docstrip_util(n) Literate programming tool docstrip_util(n) 





NAME


docstrip_util - Docstrip-related utilities






SYNOPSIS


package require Tcl 8.4


package require docstrip ?1.2?


package require docstrip::util ?1.3.1?


pkgProvide name version terminals


pkgIndex ?terminal ...?


fileoptions ?option value ...?


docstrip::util::index_from_catalogue dir
    pattern ?option value ...?


docstrip::util::modules_from_catalogue target
    source ?option value ...?


docstrip::util::classical_preamble metaprefix
    message target ?source terminals ...?


docstrip::util::classical_postamble metaprefix
    message target ?source terminals ...?


docstrip::util::packages_provided text
    ?setup-script?


docstrip::util::ddt2man text


docstrip::util::guards subcmd text


docstrip::util::patch source-var terminals
    fromtext diff ?option value ...?


docstrip::util::thefile filename ?option
    value ...?


docstrip::util::import_unidiff diff-text
    ?warning-var?










DESCRIPTION


The docstrip::util package is meant for collecting various
    utility procedures that are mainly useful at installation or development
    time. It is separate from the base package to avoid overhead when the latter
    is used to source code.






PACKAGE INDEXING COMMANDS


Like raw ".tcl" files, code lines in docstrip
    source files can be searched for package declarations and corresponding
    indices constructed. A complication is however that one cannot tell from the
    code blocks themselves which will fit together to make a working package;
    normally that information would be found in an accompanying
    ".ins" file, but parsing one of those is not an easy task.
    Therefore docstrip::util introduces an alternative encoding of such
    information, in the form of a declarative Tcl script: the catalogue
    (of the contents in a source file).


The special commands which are available inside a catalogue
  are:



  

  
Declares that the code for a package with name name and version
      version is made up from those modules in the source file which are
      selected by the terminals list of guard expression terminals. This
      code should preferably not contain a package provide command
      for the package, as one will be provided by the package loading
      mechanisms.

  

  
Declares that the code for a package is made up from those modules in the
      source file which are selected by the listed guard expression
      terminals. The name and version of this package is determined from
      package provide command(s) found in that code (hence there
      must be such a command in there).

  

  
Declares the fconfigure options that should be in force when
      reading the source; this can usually be ignored for pure ASCII files, but
      if the file needs to be interpreted according to some other
      -encoding then this is how to specify it. The command should
      normally appear first in the catalogue, as it takes effect only for
      commands following it.




Other Tcl commands are supported too — a catalogue is
    parsed by being evaluated in a safe interpreter — but they are rarely
    needed. To allow for future extensions, unknown commands in the catalogue
    are silently ignored.


To simplify distribution of catalogues together with their source
    files, the catalogue is stored in the source file itself as a module
    selected by the terminal 'docstrip.tcl::catalogue'. This supports
    both the style of collecting all catalogue lines in one place and the style
    of putting each catalogue line in close proximity of the code that it
    declares.


Putting catalogue entries next to the code they declare may look
    as follows




%    First there's the catalogue entry
%    \begin{tcl}
%<docstrip.tcl::catalogue>pkgProvide foo::bar 1.0 {foobar load}
%    \end{tcl}
%    second a metacomment used to include a copyright message
%    \begin{macrocode}
%<*foobar>
%% This file is placed in the public domain.
%    \end{macrocode}
%    third the package implementation
%    \begin{tcl}
namespace eval foo::bar {


   # ... some clever piece of Tcl code elided ...
%    \end{tcl}
%    which at some point may have variant code to make use of a
%    |load|able extension
%    \begin{tcl}
%<*load>


   load [file rootname [info script]][info sharedlibextension]
%</load>
%<*!load>


   # ... even more clever scripted counterpart of the extension


   # also elided ...
%</!load>
}
%</foobar>
%    \end{tcl}
%    and that's it!




The corresponding set-up with pkgIndex would be



%    First there's the catalogue entry
%    \begin{tcl}
%<docstrip.tcl::catalogue>pkgIndex foobar load
%    \end{tcl}
%    second a metacomment used to include a copyright message
%    \begin{tcl}
%<*foobar>
%% This file is placed in the public domain.
%    \end{tcl}
%    third the package implementation
%    \begin{tcl}
package provide foo::bar 1.0
namespace eval foo::bar {


   # ... some clever piece of Tcl code elided ...
%    \end{tcl}
%    which at some point may have variant code to make use of a
%    |load|able extension
%    \begin{tcl}
%<*load>


   load [file rootname [info script]][info sharedlibextension]
%</load>
%<*!load>


   # ... even more clever scripted counterpart of the extension


   # also elided ...
%</!load>
}
%</foobar>
%    \end{tcl}
%    and that's it!






  

  
This command is a sibling of the standard pkg_mkIndex command, in
      that it adds package entries to "pkgIndex.tcl" files. The
      difference is that it indexes docstrip-style source files rather
      than raw ".tcl" or loadable library files. Only packages
      listed in the catalogue of a file are considered.
    
The dir argument is the directory in which to look for
        files (and whose "pkgIndex.tcl" file should be
        amended). The pattern argument is a glob pattern of files
        to look into; a typical value would be *.dtx or
        *.{dtx,ddt}. Remaining arguments are option-value pairs, where
        the supported options are:

  







  

  
If this option is given, then the index_from_catalogue operation
      will be repeated in each subdirectory whose name matches the
      dirpattern. -recursein * will cause the entire
      subtree rooted at dir to be indexed.

  

  
Specify fileoptions to use when reading the catalogues of files
      (and also for reading the packages if the catalogue does not contain a
      fileoptions command). Defaults to being empty. Primarily useful if
      your system encoding is very different from that of the source file (e.g.,
      one is a two-byte encoding and the other is a one-byte encoding).
      ascii and utf-8 are not very different in that sense.

  

  
The terminals is a list of terminals in addition to
      docstrip.tcl::catalogue that should be held as true when extracting
      the catalogue. Defaults to being empty. This makes it possible to make use
      of "variant sections" in the catalogue itself, e.g. gaurd some
      entries with an extra "experimental" and thus prevent them from
      appearing in the index unless that is generated with
      "experimental" among the -options.

  

  
If the boolean is true then the return value will be a textual,
      probably multiline, report on what was done. Defaults to false, in which
      case there is no particular return value.

  

  
Every item in the report is handed as an extra argument to the command
      prefix. Since index_from_catalogue would typically be used at a
      rather high level in installation scripts and the like, the
      commandPrefix defaults to "puts stdout".
      Use list to effectively disable this feature. The return values
      from the prefix are ignored.







  

  
The package ifneeded scripts that are generated contain one
      package require docstrip command and one
      docstrip::sourcefrom command. If the catalogue entry was of the
      pkgProvide kind then the package ifneeded script also
      contains the package provide command.
    
Note that index_from_catalogue never removes anything
        from an existing "pkgIndex.tcl" file. Hence you may
        need to delete it (or have pkg_mkIndex recreate it from scratch)
        before running index_from_catalogue to update some piece of
        information, such as a package version number.

    

  





  

  
This command is an alternative to index_from_catalogue which
      creates Tcl Module (".tm") files rather than
      "pkgIndex.tcl" entries. Since this action is more similar
      to what docstrip classically does, it has features for putting pre-
      and postambles on the generated files.
    
The source argument is the name of the source file to
        generate ".tm" files from. The target argument
        is the directory which should count as a module path, i.e., this is what
        the relative paths derived from package names are joined to. The
        supported options are:

  







  

  
A message to put in the preamble (initial block of comments) of generated
      files. Defaults to a space. May be several lines, which are then separated
      by newlines. Traditionally used for copyright notices or the like, but
      metacomment lines provide an alternative to that.

  

  
Like -preamble, but the message is put at the end of the file
      instead of the beginning. Defaults to being empty.

  

  
Specify fileoptions to use when reading the catalogue of the
      source (and also for reading the packages if the catalogue does not
      contain a fileoptions command). Defaults to being empty. Primarily
      useful if your system encoding is very different from that of the source
      file (e.g., one is a two-byte encoding and the other is a one-byte
      encoding). ascii and utf-8 are not very different in that
      sense.

  

  
The terminals is a list of terminals in addition to
      docstrip.tcl::catalogue that should be held as true when extracting
      the catalogue. Defaults to being empty. This makes it possible to make use
      of "variant sections" in the catalogue itself, e.g. gaurd some
      entries with an extra "experimental" guard and thus prevent them
      from contributing packages unless those are generated with
      "experimental" among the -options.

  

  
Command prefix used to actually format the preamble. Takes four additional
      arguments message, targetFilename, sourceFilename,
      and terminalList and returns a fully formatted preamble. Defaults
      to using classical_preamble with a metaprefix of '##'.

  

  
Command prefix used to actually format the postamble. Takes four
      additional arguments message, targetFilename,
      sourceFilename, and terminalList and returns a fully
      formatted postamble. Defaults to using classical_postamble with a
      metaprefix of '##'.

  

  
If the boolean is true (which is the default) then the return value
      will be a textual, probably multiline, report on what was done. If it is
      false then there is no particular return value.

  

  
Every item in the report is handed as an extra argument to this command
      prefix. Defaults to list, which effectively disables this feature.
      The return values from the prefix are ignored. Use for example
      "puts stdout" to get report items written
      immediately to the terminal.







  

  
An existing file of the same name as one to be created will be
      overwritten.





  

  
This command returns a preamble in the classical docstrip
    style






##
## This is `TARGET',
## generated by the docstrip::util package.
##
## The original source files were:
##
## SOURCE (with options: `foo,bar')
##
## Some message line 1
## line2
## line3






  

  
if called as






docstrip::util::classical_preamble {##}\


  "\nSome message line 1\nline2\nline3" TARGET SOURCE {foo bar}






  

  
The command supports preambles for files generated from multiple sources,
      even though modules_from_catalogue at present does not need
    that.





  

  
This command returns a postamble in the classical docstrip
    style






## Some message line 1
## line2
## line3
##
## End of file `TARGET'.






  

  
if called as






docstrip::util::classical_postamble {##}\


  "Some message line 1\nline2\nline3" TARGET SOURCE {foo bar}






  

  
In other words, the source and terminals arguments are
      ignored, but supported for symmetry with classical_preamble.





  

  
This command returns a list where every even index element is the name of
      a package provided by text when that is evaluated as a Tcl
      script, and the following odd index element is the corresponding version.
      It is used to do package indexing of extracted pieces of code, in the
      manner of pkg_mkIndex.
    
One difference to pkg_mkIndex is that the text
        gets evaluated in a safe interpreter. package require commands
        are silently ignored, as are unknown commands (which includes
        source and load). Other errors cause processing of the
        text to stop, in which case only those package declarations that
        had been encountered before the error will be included in the return
        value.

    
The setup-script argument can be used to customise the
        evaluation environment, if the code in text has some very special
        needs. The setup-script is evaluated in the local context of the
        packages_provided procedure just before the text is
        processed. At that time, the name of the slave command for the safe
        interpreter that will do this processing is kept in the local variable
        c. To for example copy the contents of the ::env array to
        the safe interpreter, one might use a setup-script of

  








  $c eval [list array set env [array get ::env]]








SOURCE PROCESSING COMMANDS


Unlike the previous group of commands, which would use
    docstrip::extract to extract some code lines and then process those
    further, the following commands operate on text consisting of all types of
    lines.



  

  
The ddt2man command reformats text from the general
      docstrip format to doctools ".man" format
      (Tcl Markup Language for Manpages). The different line types are treated
      as follows:







  

  
The '%' and '%%' prefixes are removed, the rest of the text is kept as it
      is.

  

  
These are kept as they are. (Effectively this means that they will count
      as comment lines after a comment line and as code lines after a code
      line.)

  

  
example_begin and example_end commands are placed at the
      beginning and end of every block of consecutive code lines. Brackets in a
      code line are converted to lb and rb commands.

  

  
These are processed as usual, so they do not show up in the result but
      every line in a verbatim block is treated as a code line.

  

  
These are treated as code lines, except that the actual guard is
      emphasised.







  

  
At the time of writing, no project has employed doctools markup in
      master source files, so experience of what works well is not available. A
      source file could however look as follows






% [manpage_begin gcd n 1.0]
% [keywords divisor]
% [keywords math]
% [moddesc {Greatest Common Divisor}]
% [require gcd [opt 1.0]]
% [description]
%
% [list_begin definitions]
% [call [cmd gcd] [arg a] [arg b]]
%   The [cmd gcd] procedure takes two arguments [arg a] and [arg b] which
%   must be integers and returns their greatest common divisor.
proc gcd {a b} {
%   The first step is to take the absolute values of the arguments.
%   This relieves us of having to worry about how signs will be treated
%   by the remainder operation.


   set a [expr {abs($a)}]


   set b [expr {abs($b)}]
%   The next line does all of Euclid's algorithm! We can make do
%   without a temporary variable, since $a is substituted before the
%   [lb]set a $b[rb] and thus continues to hold a reference to the
%   "old" value of [var a].


   while {$b>0} { set b [expr { $a % [set a $b] }] }
%   In Tcl 8.3 we might want to use [cmd set] instead of [cmd return]
%   to get the slight advantage of byte-compilation.
%<tcl83>  set a
%<!tcl83>   return $a
}
% [list_end]
%
% [manpage_end]






  

  
If the above text is fed through docstrip::util::ddt2man then the
      result will be a syntactically correct doctools manpage, even
      though its purpose is a bit different.
    
It is suggested that master source code files with
        doctools markup are given the suffix ".ddt",
        hence the "ddt" in ddt2man.

  





  

  
The guards command returns information (mostly of a statistical
      nature) about the ordinary docstrip guards that occur in the text.
      The subcmd selects what is returned.







  

  
List the guard expression terminals with counts. The format of the return
      value is a dictionary which maps the terminal name to the number of
      occurencies of it in the file.

  

  
List the guard expressions with counts. The format of the return value is
      a dictionary which maps the expression to the number of occurencies of it
      in the file.

  

  
List the syntactically incorrect guard expressions (e.g. parentheses do
      not match, or a terminal is missing). The return value is a list, with the
      elements in no particular order.

  

  
List the guard expressions. The return value is a list, with the elements
      in no particular order.

  

  
List the guard expressions with modifiers. The format of the return value
      is a dictionary where each index is a guard expression and each entry is a
      string with one character for every guard line that has this expression.
      The characters in the entry specify what modifier was used in that line:
      +, -, *, /, or (for guard without modifier:) space. This is the most
      primitive form of the information gathered by guards.

  

  
List the guard expression terminals. The return value is a list, with the
      elements in no particular order.

  

  
List the malformed guard lines (this does not include lines where only the
      expression is malformed, though). The format of the return value is a
      dictionary which maps line numbers to their contents.







  

  
This command tries to apply a diff file (for example a contributed
      patch) that was computed for a generated file to the docstrip
      source. This can be useful if someone has edited a generated file, thus
      mistaking it for being the source. This command makes no presumptions
      which are specific for the case that the generated file is a Tcl script.
    
patch requires that the source file to patch is kept as
        a list of lines in a variable, and the name of that variable in the
        calling context is what goes into the source-var argument. The
        terminals is the list of terminals used to extract the file that
        has been patched. The diff is the actual diff to apply (in a
        format as explained below) and the fromtext is the contents of
        the file which served as "from" when the diff was computed.
        Options can be used to further control the process.

    
The process works by "lifting" the hunks in the
        diff from generated to source file, and then applying them to the
        elements of the source-var. In order to do this lifting, it is
        necessary to determine how lines in the fromtext correspond to
        elements of the source-var, and that is where the
        terminals come in; the source is first extracted under the
        given terminals, and the result of that is then matched against
        the fromtext. This produces a map which translates line numbers
        stated in the diff to element numbers in source-var, which
        is what is needed to lift the hunks.

    
The reason that both the terminals and the
        fromtext must be given is twofold. First, it is very difficult to
        keep track of how many lines of preamble are supplied some other way
        than by copying lines from source files. Second, a generated file might
        contain material from several source files. Both make it impossible to
        predict what line number an extracted file would have in the generated
        file, so instead the algorithm for computing the line number map looks
        for a block of lines in the fromtext which matches what can be
        extracted from the source. This matching is affected by the following
        options:

  







  

  
How equal must two lines be in order to match? The supported modes
      are:







  

  
Lines must be equal as strings. This is the default.

  

  
All sequences of whitespace characters are converted to single spaces
      before comparing.

  

  
Only non-whitespace characters are considered when comparing.

  

  
Any two lines are considered to be equal.







  

  
The -metaprefix value to use when extracting. Defaults to
      "%%", but for Tcl code it is more likely that "#" or
      "##" had been used for the generated file.

  

  
The -trimlines value to use when extracting. Defaults to true.







  

  
The return value is in the form of a unified diff, containing only those
      hunks which were not applied or were only partially applied; a comment in
      the header of each hunk specifies which case is at hand. It is normally
      necessary to manually review both the return value from patch and
      the patched text itself, as this command cannot adjust comment lines to
      match new content.
    
An example use would look like

  






set sourceL [split [docstrip::util::thefile from.dtx] \n]
set terminals {foo bar baz}
set fromtext [docstrip::util::thefile from.tcl]
set difftext [exec diff --unified from.tcl to.tcl]
set leftover [docstrip::util::patch sourceL $terminals $fromtext\


  [docstrip::util::import_unidiff $difftext] -metaprefix {#}]
set F [open to.dtx w]; puts $F [join $sourceL \n]; close $F
return $leftover






  

  
Here, "from.dtx" was used as source for
      "from.tcl", which someone modified into
      "to.tcl". We're trying to construct a
      "to.dtx" which can be used as source for
      "to.tcl".





  

  
The thefile command opens the file filename, reads it to
      end, closes it, and returns the contents (dropping a final newline if
      there is one). The option-value pairs are passed on to fconfigure
      to configure the open file channel before anything is read from it.

  

  
This command parses a unified (diff flags -U and
      --unified) format diff into the list-of-hunks format expected by
      docstrip::util::patch. The diff-text argument is the text to
      parse and the warning-var is, if specified, the name in the calling
      context of a variable to which any warnings about parsing problems will be
      appended.
    
The return value is a list of hunks. Each hunk is a
        list of five elements "start1 end1 start2
        end2 lines". start1 and end1 are line
        numbers in the "from" file of the first and last respectively
        lines of the hunk. start2 and end2 are the corresponding
        line numbers in the "to" file. Line numbers start at 1. The
        lines is a list with two elements for each line in the hunk; the
        first specifies the type of a line and the second is the actual line
        contents. The type is - for lines only in the "from"
        file, + for lines that are only in the "to" file, and
        0 for lines that are in both.

  








SEE ALSO


docstrip, doctools, doctools_fmt






KEYWORDS


\.ddt, .dtx, LaTeX, Tcl module, catalogue, diff, docstrip,
    doctools, documentation, literate programming, module, package indexing,
    patch, source






CATEGORY


Documentation tools






COPYRIGHT


Copyright (c) 2003–2010 Lars Hellström <Lars dot Hellstrom at residenset dot net>








  

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