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rak

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NAME

rak - plumbing to be able to look for stuff

SYNOPSIS

use rak;

# look for "foo" in all .txt files from current directory
my $rak = rak / foo /, :file(/ \.txt $/);

# show results
for $rak.result -> (:key($path), :value(@found)) {
    if @found {
        say "$path:";
        say .key ~ ':' ~ .value for @found;
    }
}

DESCRIPTION

The rak subroutine provides a mostly abstract core search (plumbing) functionality to be used by modules such as (porcelain) App::Rak.

THEORY OF OPERATION

The rak subroutine basically goes through 6 steps to produce a Rak object.

1. Acquire sources

The first step is determining the objects that should be searched for the specified pattern. If an object is a Str, it will be assume that it is a path specification of a file to be searched in some form and an IO::Path object will be created for it.

Related named arguments are (in alphabetical order):

The result of this step, is a (potentially lazy and hyperable) sequence of objects.

2. Filter applicable objects

Filter down the list of sources from step 1 on any additional filesystem related properties. This assumes that the list of objects created are strings of absolute paths to be checked.

The result of this step, is a (potentially lazy and hyperable) sequence of objects.

3. Produce items to search in (apply transformers)

The second step is to create the logic for creating items to search in from the objects in step 2. If search is to be done per object, then .slurp is called on the object. Otherwise .lines is called on the object. Unless one provides their own logic for producing items to search in.

Related named arguments are (in alphabetical order):

The result of this step, is a (potentially lazy and hyperable) sequence of objects.

4. Create logic for matching

Take the logic of the pattern Callable, and create a Callable to do the actual matching with the items produced in step 3.

Related named arguments are (in alphabetical order):

5. Create logic for running

Take the matcher logic of the Callable of step 4 and create a runner Callable that will produce the items found and their possible context (such as extra items before or after). Assuming no context, the runner changes a return value of False from the matcher into Empty, a return value of True in the original item, and passes through any other value.

Related named arguments are (in alphabetical order):

Matching items are represented by PairMatched objects, and items that have been added because of the above context arguments, are represented by PairContext objects. Unless :omit-item-number has been specified with a trueish value, in which case items will always be just a string, whether they matched or not (if part of a context specification).

6. Run the sequence(s)

The final step is to take the Callable of step 5 and run that repeatedly on the sequence of step 2. Make sure any phasers (FIRST, NEXT and LAST) are called at the appropriate time in a thread-safe manner. Inside the Callable of step 5, the dynamic variable $*SOURCE will be set to the source of the items being checked.

Either produces a sequence in which the key is the source, and the value is a Slip of Pairs where the key is the item-number and the value is item with the match, or whatever the pattern matcher returned.

Or, produces sequence of whatever a specified mapper returned and/or with uniqueifying enabled.

Related named arguments are (in alphabetical order):

EXPORTED CLASSES

Rak

The return value of a rak search. Contains the following attributes:

result

An Iterable with search results. This could be a lazy Seq or a fully vivified List (see below).

completed

A Bool indicating whether the search has already been completed. This is typically True if statistics were asked to be collected, or the pattern Callable contained LAST phasers.

stats

A Map with any statistics collected (so far, in case an exception was thrown). If the Map is not empty, it contains the following keys:

exception

Any Exception object that was caught.

PairContext

A subclass of Pair of which the matched method returns False. Used for non-matching items when item-numbers are required to be returned and a certain item context was requested.

PairMatched

A subclass of PairContext of which the matched method returns True. Used for matching items when item-numbers are required to be returned.

EXPORTED SUBROUTINES

rak

The rak subroutine takes a Callable (or Regex) pattern as the only positional argument and quite a number of named arguments. Or it takes a Callable (or Regex) as the first positional argument for the pattern, and a hash with named arguments as the second positional argument. In the latter case, the hash will have the arguments removed that the rak subroutine needed for its configuration and execution.

Return value

A Rak object (see above) is always returned. The object provides four attributes: result (with the result Iterable), completed (a Bool indicating whether all searching has been done already), stats (Map with any statistics) and exception (any Exception object or Nil).

Result Iterable

If the :unique argument was specified with a trueish value, then the result Iterable will just produce the unique values that were either explicitely returned by the matcher, or the unique items that matched.

Otherwise the value is an Iterable of Pairs which contain the source object as key (by default the absolute path of the file in which the pattern was found).

If there was only one item produced per source, then the value will be that value, or whatever was produced by the matching logic.

Otherwise the value will be a Slip. If no item numbers were requested, each element contains the result of matching. If item-numbers were requested, each element is a Pair, of which the key is the item-number where the pattern was found, and the value is the product of the search (which, by default, is the item in which the pattern was found).

In a graph:

rak(...)
 |- Rak
     |- exception: Exception object or Nil
     |- stats: Map with statistics (if any)
     |- completed: Bool whether all searching done already
     |- result: Iterable
          |- Pair
          |   |- key: source object
          |   |- value:
          |        |- Slip
          |        |   |- PairMatched|PairContext
          |        |   |   |- key: item-number
          |        |   |   \- value: match result
          |        |   or
          |        |   \- match result
          |        or
          |        \- single item match result
          or
          \- unique match result

Named Arguments

The following named arguments can be specified (in alphabetical order):

:accessed(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the access time of the path. The Callable is passed a Num value of the access time (number of seconds since epoch) and is expected to return a trueish value to have the path be considered for further selection.

:after-context(N)

Indicate the number of items that should also be returned after an item with a pattern match. Defaults to 0.

:batch(N)

When hypering over multiple cores, indicate how many items should be processed per thread at a time. Defaults to whatever the system thinks is best (which may be sub-optimal).

:before-context(N)

Indicate the number of items that should also be returned before an item with a pattern match. Defaults to 0.

:blocks(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the number of blocks used by the path on the filesystem on which the path is located. The Callable is passed the number of blocks of a path and is expected to return a trueish value to have the path be considered for further selection.

:context(N)

Indicate the number of items that should also be returned around an item with a pattern match. Defaults to 0.

:created(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the creation time of the path. The Callable is passed a Num value of the creation time (number of seconds since epoch) and is expected to return a trueish value to have the path be considered for further selection.

:degree(N)

When hypering over multiple cores, indicate the maximum number of threads that should be used. Defaults to whatever the system thinks is best (which may be sub-optimal).

:device-number(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the device number of the path. The Callable is passed the device number of the device on which the path is located and is expected to return a trueish value to have the path be considered for further selection.

:dir(&dir-matcher)

If specified, indicates the matcher that should be used to select acceptable directories with the paths utility. Defaults to True indicating all directories should be recursed into. Applicable for any situation where paths is used to create the list of files to check.

:dont-catch

Flag. If specified with a trueish value, will not catch any error during processing, but will throw any error again. Defaults to False, making sure that errors will be caught.

:eager

Flag. If specified with a trueish value, will always produce all results before returning the Rak object. Defaults to False, making result production lazy if possible.

:encoding("utf8-c8")

When specified with a string, indicates the name of the encoding to be used to produce items to check (typically by calling lines or slurp). Defaults to utf8-c8, the UTF-8 encoding that is permissive of encoding issues.

:exec($invocation)

If specified, indicates the name of a program and its arguments to be executed. Any $_ in the invocation string will be replaced by the file being checked. The file will be included if the program runs to a successful conclusion.

:file(&file-matcher)

If specified, indicates the matcher that should be used to select acceptable files with the paths utility. Defaults to True indicating all files should be checked. Applicable for any situation where paths is used to create the list of files to check.

:filesize(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the number of bytes of the path. The Callable is passed the number of bytes of a path and is expected to return a trueish value to have the path be considered for further selection.

:files-from($filename)

If specified, indicates the name of the file from which a list of files to be used as sources will be read.

:find

Flag. If specified, maps the sources of items into items to search.

:frequencies

Flag. If specified, produces key/value Pairs in which the key is the item, and the value is the frequency with which the item was seen.

:gid(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the gid of the path. The Callable is passed the numeric gid of a path and is expected to return a trueish value to have the path be considered for further selection. See also owner and group filters.

:hard-links(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the number of hard-links of the path. The Callable is passed the number of hard-links of a path and is expected to return a trueish value to have the path be considered for further selection.

:has-setgid

Flag. If specified, indicates paths that have the SETGID bit set in their attributes, are (not) acceptable for further selection. Usually only makes sense when uses together with :find.

:has-setuid

Flag. If specified, indicates paths that have the SETUID bit set in their attributes, are (not) acceptable for further selection. Usually only makes sense when uses together with :find.

:inode(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the inode of the path. The Callable is passed the inode of a path and is expected to return a trueish value to have the path be considered for further selection.

:invert-match

Flag. If specified with a trueish value, will negate the return value of the pattern if a Bool was returned. Defaults to False.

:is-empty

Flag. If specified, indicates paths, that are empty (aka: have a filesize of 0 bytes), are (not) acceptable for further selection. Usually only makes sense when uses together with :find.

:is-executable

Flag. If specified, indicates paths, that are executable by the current user, are (not) acceptable for further selection.

:is-group-executable

Flag. If specified, indicates paths, that are executable by the current group, are (not) acceptable for further selection.

:is-group-readable

Flag. If specified, indicates paths, that are readable by the current group, are (not) acceptable for further selection.

:is-group-writable

Flag. If specified, indicates paths, that are writable by the current group, are (not) acceptable for further selection.

:is-readable

Flag. If specified, indicates paths, that are readable by the current user, are (not) acceptable for further selection.

:is-owned-by-group

Flag. If specified, indicates only paths that are owned by the group of the current user, are (not) acceptable for further selection.

:is-owned-by-user

Flag. If specified, indicates only paths that are owned by the current user, are (not) acceptable for further selection.

:is-owner-executable

Flag. If specified, indicates paths, that are executable by the owner, are (not) acceptable for further selection.

:is-owner-readable

Flag. If specified, indicates paths, that are readable by the owner, are (not) acceptable for further selection.

:is-owner-writable

Flag. If specified, indicates paths, that are writable by the owner, are (not) acceptable for further selection.

:is-sticky

Flag. If specified, indicates paths that have the STICKY bit set in their attributes, are (not) acceptable for further selection. Usually only makes sense when uses together with :find.

Flag. If specified, indicates only paths that are symbolic links, are (not) acceptable for further selection.

:is-world-executable

Flag. If specified, indicates paths, that are executable by any user or group, are (not) acceptable for further selection.

:is-world-readable

Flag. If specified, indicates paths, that are readable by any user or group, are (not) acceptable for further selection.

:is-world-writeable

Flag. If specified, indicates paths, that are writable by any user or group, are (not) acceptable for further selection.

:is-writable

Flag. If specified, indicates paths, that are writable by the current user, are (not) acceptable for further selection.

:mapper(&mapper)

If specified, indicates the Callable that will be called (in a thread-safe manner) for each source, with the matches of that source. The Callable is passed the source object, and a list of matches, if there were any matches. If you want the Callable to be called for every source, then you must also specify :map-all.

Whatever the mapper Callable returns, will become the result of the call to the rak subroutine. If you don't want any result to be returned, you can return Empty from the mapper Callable.

:map-all

Flag. If specified with a trueish value, will call the mapper logic, as specified with :mapper, even if a source has no matches. Defaults to False.

:max-matches-per-source(N)

Indicate the maximum number of items that may be produce per source. Defaults to all (which can also be specified by an falsish value).

:meta-modified(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the modification time of the path. The Callable is passed a Num value of the modification time (number of seconds since epoch) and is expected to return a trueish value to have the path be considered for further selection.

:mode(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the mode of the path. The Callable is passed the mode of a path and is expected to return a trueish value to have the path be considered for further selection. This is really for advanced types of tests: it's probably easier to use any of the readable, writeable and executable filters.

:modified(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the modification time of the path. The Callable is passed a Num value of the modification time (number of seconds since epoch) and is expected to return a trueish value to have the path be considered for further selection.

:old-new

Flag. If specified with a trueish value, will produce Pairs of the current value being investigated, and whatever was returned by the Callable pattern for that value (if what was returned was not a Bool, Empty or Nil) if that value was different from the original value. Defaults to False, meaning to just produce according to what was returned.

:omit-item-number

Flag. If specified with a trueish value, won't produce any PairMatched or PairContext objects in the result, but will just produce the result of the match. Defaults to False, meaning to include item numbers.

:paragraph-context

Flag. If specified with a trueish value, produce items around the empty with a pattern match until a falsish item is encountered.

:passthru

Flag. If specified with a trueish value, produces all items always.

:passthru-context

Flag. If specified with a trueish value, produces all items if there is at least one match.

:paths-from($filename)

If specified, indicates the name of the file from which a list of paths to be used as the base of the production of filename with a paths search.

:paths(@paths)

If specified, indicates a list of paths that should be used as the base of the production of filename with a paths search. If there is no other sources specification (from either the :files-from, :paths-from or :sources) then the current directory (aka ".") will be assumed. If that directory appears to be the top directory in a git repository, then :under-version-control will be assumed, only producing files that are under version control under that directory.

If a single hyphen is specified as the path, then STDIN will be assumed as the source.

:produce-many(&producer)

If specified, indicates a Callable that will be called given a source, and is expected to produce zero or more items to be inspected. Defaults to a producer that calles the lines method on a given source, with the :encoding and :with-line-ending arguments.

The Callable should return Empty if for some reason nothing could be produced.

:produce-one(&producer)

If specified, indicates a Callable that will be called given a source, and is expected to produce one items to be inspected.

The Callable should return Nil if for some reason nothing could be produced).

:recurse-symlinked-dir

Flag. If specified with a trueish value, will recurse into directories that are actually symbolic links. The default is False: do not recurse into symlinked directories.

:recurse-unmatched-dir

Flag. If specified with a trueish value, will recurse into directories that did not pass the :. No files will ever be produced from such directories, but further recursion will be done if directories are encountered. The default is False: do not recurse into directories that didn't match the :dir specification.

:quietly

Flag. If specified with a trueish value, will absorb any warnings that may occur when looking for the pattern.

:shell($invocation)

If specified, indicates the command(s) to be executed in a shell. Any $_ in the invocation string will be replaced by the file being checked. The file will be included if the shell command(s) run to a successful conclusion.

:silently("out,err")

When specified with True, will absorb any output on STDOUT and STDERR. Optionally can only absorb STDOUT ("out"), STDERR ("err") and both STDOUT and STDERR ("out,err").

:sources(@objects)

If specified, indicates a list of objects that should be used as a source for the production of items. Which generally means they cannot be just strings.

:sources-only

Flag. If specified with a trueish value, will only produce the source of a match once per source. Defaults to False.

:sources-without-only

Flag. If specified with a trueish value, will only produce the source of a match if there is not a single match. Defaults to False.

:stats

Flag. If specified with a trueish value, will keep stats on number of files and number of items seen, and make that available in the stats attribute of the Rak object.

:stats-only

Flag. If specified with a trueish value, will perform all searching, but only update counters and not produce any result. The statistics will be available in the stats attribute, and the result attribute will be Empty.

:uid(&filter)

If specified, indicates the Callable filter that should be used to select acceptable paths by the uid of the path. The Callable is passed the numeric uid of a path and is expected to return a trueish value to have the path be considered for further selection. See also owner and group filters.

:under-version-control($name = 'git')

If specified, indicates that any path specification that is a directory, should be considered as the root of a directory structure under some form of version control. If specified as True, will assume git. If such a path is under version control, then only files that are actually controlled, will be produced for further inspection. If it is not under version control, no files will be produced.

Currently, only git is supported.

:unique

Flag. If specified, indicates that only unique matches will be returned, instead of the normal sequence of source => result pairs.

:with-line-ending

Flag. If specified, indicates line endings are to be kept when producing items to check. Defaults to False, meaning that line endings are removed from items to check. Only applicable with line-based checking.

PATTERN RETURN VALUES

The return value of the pattern Callable match is interpreted in the following way:

True

If the Boolean True value is returned, assume the pattern is found. Produce the item unless :invert-match was specified.

False

If the Boolean False value is returned, assume the pattern is not found. Do not produce the item unless :invert-match was specified.

Nil

If Nil is returned, assume the pattern is not found. This can typically happen when a try is used in a pattern, and an execution error occurred. Do not produce the item unless :invert-match was specified.

Empty

If the empty Slip is returned, assume the pattern is not found. Do not produce the item unless :invert-match was specified. Shown in stats as a passthru.

any other value

Produce that value.

PHASERS

Any FIRST, NEXT and LAST phaser that are specified in the pattern Callable, will be executed at the correct time.

MATCHED ITEMS vs CONTEXT ITEMS

The Pairs that contain the search result within an object, have an additional method mixed in: matched. This returns True for items that matched, and False for items that have been added because of a context specification (:context, :before-context, :after-context, paragraph-context or passthru-context).

These Pairs can also be recognized by their class: PairMatched versus PairContext, which are also exported.

AUTHOR

Elizabeth Mattijsen liz@raku.rocks

Source can be located at: https://github.com/lizmat/rak . Comments and Pull Requests are welcome.

If you like this module, or what I’m doing more generally, committing to a small sponsorship would mean a great deal to me!

COPYRIGHT AND LICENSE

Copyright 2022 Elizabeth Mattijsen

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.