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textutil.3tcl

---

NAME

textutil - Procedures to manipulate texts and strings.

SYNOPSIS

package require Tcl 8.2

package require textutil ?0.7.1?

::textutil::adjust string args

::textutil::adjust::readPatterns filename

::textutil::adjust::listPredefined

::textutil::adjust::getPredefined filename

::textutil::indent string prefix ?skip?

::textutil::undent string

::textutil::splitn string ?len?

::textutil::splitx string ?regexp?

::textutil::tabify string ?num?

::textutil::tabify2 string ?num?

::textutil::trim string ?regexp?

::textutil::trimleft string ?regexp?

::textutil::trimright string ?regexp?

::textutil::trimPrefix string prefix

::textutil::trimEmptyHeading string

::textutil::untabify string ?num?

::textutil::untabify2 string ?num?

::textutil::strRepeat text num

::textutil::blank num

::textutil::chop string

::textutil::tail string

::textutil::cap string

::textutil::uncap string

::textutil::longestCommonPrefixList list

::textutil::longestCommonPrefix ?string...?

---

DESCRIPTION

The package textutil provides commands that manipulate strings or texts (a.k.a. long strings or string with embedded newlines or paragraphs). It is actually a bundle providing the commands of the six packages

textutil::adjust

textutil::repeat

textutil::split

textutil::string

textutil::tabify

textutil::trim

in the namespace textutil.

The bundle is deprecated, and it will be removed in a future release of Tcllib, after the next release. It is recommended to use the relevant sub packages instead for whatever functionality is needed by the using package or application.

The complete set of procedures is described below.

::textutil::adjust string args

Do a justification on the string according to args. The string is taken as one big paragraph, ignoring any newlines. Then the line is formatted according to the options used, and the command return a new string with enough lines to contain all the printable chars in the input string. A line is a set of chars between the beginning of the string and a newline, or between 2 newlines, or between a newline and the end of the string. If the input string is small enough, the returned string won't contain any newlines.

Together with ::textutil::indent it is possible to create properly wrapped paragraphs with arbitrary indentations.

By default, any occurrence of spaces characters or tabulation are replaced by a single space so each word in a line is separated from the next one by exactly one space char, and this forms a real line. Each real line is placed in a logical line, which have exactly a given length (see -length option below). The real line may have a lesser length. Again by default, any trailing spaces are ignored before returning the string (see -full option below). The following options may be used after the string parameter, and change the way the command place a real line in a logical line.

-full boolean

If set to false, any trailing space chars are deleted before returning the string. If set to true, any trailing space chars are left in the string. Default to false.

-hyphenate boolean

if set to false, no hyphenation will be done. If set to true, the last word of a line is tried to be hyphenated. Defaults to false. Note: hyphenation patterns must be loaded prior, using the command ::textutil::adjust::readPatterns.

-justify center|left|plain|right

Set the justification of the returned string to center, left, plain or right. By default, it is set to left. The justification means that any line in the returned string but the last one is build according to the value. If the justification is set to plain and the number of printable chars in the last line is less than 90% of the length of a line (see -length), then this line is justified with the left value, avoiding the expansion of this line when it is too small. The meaning of each value is:

center

The real line is centered in the logical line. If needed, a set of space characters are added at the beginning (half of the needed set) and at the end (half of the needed set) of the line if required (see the option -full).

left

The real line is set on the left of the logical line. It means that there are no space chars at the beginning of this line. If required, all needed space chars are added at the end of the line (see the option -full).

plain

The real line is exactly set in the logical line. It means that there are no leading or trailing space chars. All the needed space chars are added in the real line, between 2 (or more) words.

right

The real line is set on the right of the logical line. It means that there are no space chars at the end of this line, and there may be some space chars at the beginning, despite of the -full option.

-length integer

Set the length of the logical line in the string to integer. integer must be a positive integer value. Defaults to 72.

-strictlength boolean

If set to false, a line can exceed the specified -length if a single word is longer than -length. If set to true, words that are longer than -length are split so that no line exceeds the specified -length. Defaults to false.

::textutil::adjust::readPatterns filename

Loads the internal storage for hyphenation patterns with the contents of the file filename. This has to be done prior to calling command ::textutil::adjust with "-hyphenate true", or the hyphenation process will not work correctly.

The package comes with a number of predefined pattern files, and the command ::textutil::adjust::listPredefined can be used to find out their names.

::textutil::adjust::listPredefined

This command returns a list containing the names of the hyphenation files coming with this package.

::textutil::adjust::getPredefined filename

Use this command to query the package for the full path name of the hyphenation file filename coming with the package. Only the filenames found in the list returned by ::textutil::adjust::listPredefined are legal arguments for this command.

::textutil::indent string prefix ?skip?

Each line in the string indented by adding the string prefix at its beginning. The modified string is returned as the result of the command.

If skip is specified the first skip lines are left untouched. The default for skip is 0, causing the modification of all lines. Negative values for skip are treated like 0. In other words, skip > 0 creates a hanging indentation.

Together with ::textutil::adjust it is possible to create properly wrapped paragraphs with arbitrary indentations.

::textutil::undent string

The command computes the common prefix for all lines in string consisting solely out of whitespace, removes this from each line and returns the modified string.

Lines containing only whitespace are always reduced to completely empty lines. They and empty lines are also ignored when computing the prefix to remove.

Together with ::textutil::adjust it is possible to create properly wrapped paragraphs with arbitrary indentations.

::textutil::splitn string ?len?

This command splits the given string into chunks of len characters and returns a list containing these chunks. The argument len defaults to 1 if none is specified. A negative length is not allowed and will cause the command to throw an error. Providing an empty string as input is allowed, the command will then return an empty list. If the length of the string is not an entire multiple of the chunk length, then the last chunk in the generated list will be shorter than len.

::textutil::splitx string ?regexp?

Split the string and return a list. The string is split according to the regular expression regexp instead of a simple list of chars. Note that if you add parenthesis into the regexp, the parentheses part of separator would be added into list as additional element. If the string is empty the result is the empty list, like for split. If regexp is empty the string is split at every character, like split does. The regular expression regexp defaults to "[\\t \\r\\n]+".

::textutil::tabify string ?num?

Tabify the string by replacing any substring of num space chars by a tabulation and return the result as a new string. num defaults to 8.

::textutil::tabify2 string ?num?

Similar to ::textutil::tabify this command tabifies the string and returns the result as a new string. A different algorithm is used however. Instead of replacing any substring of num spaces this command works more like an editor. num defaults to 8.

Each line of the text in string is treated as if there are tabstops every num columns. Only sequences of space characters containing more than one space character and found immediately before a tabstop are replaced with tabs.

::textutil::trim string ?regexp?

Remove in string any leading and trailing substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trimleft string ?regexp?

Remove in string any leading substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trimright string ?regexp?

Remove in string any trailing substring according to the regular expression regexp and return the result as a new string. This apply on any line in the string, that is any substring between 2 newline chars, or between the beginning of the string and a newline, or between a newline and the end of the string, or, if the string contain no newline, between the beginning and the end of the string. The regular expression regexp defaults to "[ \\t]+".

::textutil::trimPrefix string prefix

Removes the prefix from the beginning of string and returns the result. The string is left unchanged if it doesn't have prefix at its beginning.

::textutil::trimEmptyHeading string

Looks for empty lines (including lines consisting of only whitespace) at the beginning of the string and removes it. The modified string is returned as the result of the command.

::textutil::untabify string ?num?

Untabify the string by replacing any tabulation char by a substring of num space chars and return the result as a new string. num defaults to 8.

::textutil::untabify2 string ?num?

Untabify the string by replacing any tabulation char by a substring of at most num space chars and return the result as a new string. Unlike textutil::untabify each tab is not replaced by a fixed number of space characters. The command overlays each line in the string with tabstops every num columns instead and replaces tabs with just enough space characters to reach the next tabstop. This is the complement of the actions taken by ::textutil::tabify2. num defaults to 8.

There is one asymmetry though: A tab can be replaced with a single space, but not the other way around.

::textutil::strRepeat text num

The implementation depends on the core executing the package. Used string repeat if it is present, or a fast tcl implementation if it is not. Returns a string containing the text repeated num times. The repetitions are joined without characters between them. A value of num <= 0 causes the command to return an empty string.

::textutil::blank num

A convenience command. Returns a string of num spaces.

::textutil::chop string

A convenience command. Removes the last character of string and returns the shortened string.

::textutil::tail string

A convenience command. Removes the first character of string and returns the shortened string.

::textutil::cap string

Capitalizes the first character of string and returns the modified string.

::textutil::uncap string

The complementary operation to ::textutil::cap. Forces the first character of string to lower case and returns the modified string.

::textutil::longestCommonPrefixList list

::textutil::longestCommonPrefix ?string...?

Computes the longest common prefix for either the strings given to the command, or the strings specified in the single list, and returns it as the result of the command.

If no strings were specified the result is the empty string. If only one string was specified, the string itself is returned, as it is its own longest common prefix.

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 SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for either package and/or documentation.

SEE ALSO

regexp(3tcl), split(3tcl), string(3tcl)

KEYWORDS

TeX, formatting, hyphenation, indenting, paragraph, regular expression, string, trimming

CATEGORY

Text processing