Syntax::Highlight::PerUsermContributed PerSyntax::Highlight::Perl::Improved(3)NAMESyntax::Highlight::Perl::Improved - Highlighting of Perl Syntactical
Structures
VERSION
This file documents Syntax::Highlight::Perl::Improved version 1.0.
SYNOPSIS
# simple procedural
use Syntax::Highlight::Perl::Improved ':BASIC'; # or ':FULL'
print format_string($my_string);
# OO
use Syntax::Highlight::Perl::Improved;
my $formatter = new Syntax::Highlight::Perl::Improved;
print $formatter->format_string($my_string);
DESCRIPTION
This module provides syntax highlighting for Perl code. The design
bias is roughly line-oriented and streamed (ie, processing a file line-
by-line in a single pass). Provisions may be made in the future for
tasks related to "back-tracking" (ie, re-doing a single line in the
middle of a stream) such as speeding up state copying.
Constructors
The only constructor provided is "new()". When called on an existing
object, "new()" will create a new copy of that object. Otherwise,
"new()" creates a new copy of the (internal) Default Object. Note that
the use of the procedural syntax modifies the Default Object and that
those changes will be reflected in any subsequent "new()" calls.
Formatting
Formatting is done using the "format_string()" method. Call
"format_string()" with one or more strings to format, or it will
default to using $_.
Setting and Getting Formats
You can set the text used for formatting a syntax element using
"set_format()" (or set the start and end format individually using
"set_start_format()" and "set_end_format()", respectively).
You can also retrieve the text used for formatting for an element via
"get_start_format()" or "get_end_format". Bulk retrieval of the names
or values of defined formats is possible via "get_format_names_list()"
(names), "get_start_format_values_list()" and
"get_end_format_values_list()".
See "FORMAT TYPES" later in this document for information on what
format elements can be used.
Checking and Setting the State
You can check certain aspects of the state of the formatter via the
methods: "in_heredoc()", "in_string()", "in_pod()", "was_pod()",
"in_data()", and "line_count()".
You can reset all of the above states (and a few other internal ones)
using "reset()".
Stable and Unstable Formatting Modes
You can set or check the stability of formatting via "unstable()".
In unstable (TRUE) mode, formatting is not considered to be persistent
with nested formats. Or, put another way, when unstable, the formatter
can only "remember" one format at a time and must reinstate formatting
for each token. An example of unstable formatting is using ANSI color
escape sequences in a terminal.
In stable (FALSE) mode (the default), formatting is considered
persistent within arbitrarily nested formats. Even in stable mode,
however, formatting is never allowed to span multiple lines; it is
always fully closed at the end of the line and reinstated at the
beginning of a new line, if necessary. This is to ensure properly
balanced tags when only formatting a partial code snippet. An example
of stable formatting is HTML.
Substitutions
Using "define_substitution()", you can have the formatter substitute
certain strings with others, after the original string has been parsed
(but before formatting is applied). This is useful for escaping
characters special to the output mode (eg, > and < in HTML) without
them affecting the way the code is parsed.
You can retrieve the current substitutions (as a hash-ref) via
"substitutions()".
FORMAT TYPES
The Syntax::Highlight::Perl::Improved formatter recognizes and
differentiates between many Perl syntactical elements. Each type of
syntactical element has a Format Type associated with it. There is
also a 'DEFAULT' type that is applied to any element who's Format Type
does not have a value.
Several of the Format Types have underscores in their name. This
underscore is special, and indicates that the Format Type can be
"generalized." This means that you can assign a value to just the
first part of the Format Type name (the part before the underscore) and
that value will be applied to all Format Types with the same first
part. For example, the Format Types for all types of variables begin
with "Variable_". Thus, if you assign a value to the Format Type
"Variable", it will be applied to any type of variable. Generalized
Format Types take precedence over non-generalized Format Types. So the
value assigned to "Variable" would be applied to "Variable_Scalar",
even if "Variable_Scalar" had a value explicitly assigned to it.
You can also define a "short-cut" name for each Format Type that can be
generalized. The short-cut name would be the part of the Format Type
name after the underscore. For example, the short-cut for
"Variable_Scalar" would be "Scalar". Short-cut names have the least
precedence and are only assigned if neither the generalized Type name,
nor the full Type name have values.
Following is a list of all the syntactical elements that
Syntax::Highlight::Perl::Improved currently recognizes, along with a
short description of what each would be applied to.
Comment_Normal
A normal Perl comment. Starts with '#' and goes until the end of
the line.
Comment_POD
Inline documentation. Starts with a line beginning with an equal
sign ('=') followed by a word (eg: '=pod') and continuing until a
line beginning with '=cut'.
Directive
Either the "she-bang" line at the beginning of the file, or a line
directive altering what the compiler thinks the current line and
file is.
Label
A loop or statement label (to be the target of a goto, next, last
or redo).
Quote
Any string or character that begins or ends a String. Including,
but not necessarily limited to: quote-like regular expression
operators ("m//", "s///", "tr///", etc), a Here-Document
terminating line, the lone period terminating a format, and, of
course, normal quotes ("'", """, "`", "q{}", "qq{}", "qr{}",
"qx{}").
String
Any text within quotes, "format"s, Here-Documents, Regular
Expressions, and the like.
Subroutine
The identifier used to define, identify, or call a subroutine (or
method). Note that Syntax::Highlight::Perl::Improved cannot
recognize a subroutine if it is called without using parentheses or
an ampersand, or methods called using the indirect object syntax.
It formats those as barewords.
Variable_Scalar
A scalar variable.
Note that (theoretically) this format is not applied to non-scalar
variables that are being used as scalars (ie: array or hash
lookups, nor references to anything other than scalars).
Syntax::Highlight::Perl::Improved figures out (or at least tries
to) the actual type of the variable being used (by looking at how
you're subscripting it) and formats it accordingly. The first
character of the variable (ie, the "$", "@", "%", or "*") tells you
the type of value being used, and the color (hopefully) tells you
the type of variable being used to get that value.
(See "KNOWN ISSUES" for information about when this doesn't work
quite right.)
Variable_Array
An array variable (but not usually a slice; see above).
Variable_Hash
A hash variable.
Variable_Typeglob
A typeglob. Note that typeglobs not beginning with an asterisk (*)
(eg: filehandles) are formatted as barewords. This is because,
well, they are.
Whitespace
Whitespace. Not usually formatted but it can be.
Character
A special, or backslash-escaped, character. For example: "\n"
(newline), or "\d" (digits).
Only occurs within strings or regular expressions.
Keyword
A Perl keyword. Some examples include: my, local, sub, next.
Note that Perl does not make any distinction between keywords and
built-in functions (at least not in the documentation). Thus I had
to make a subjective call as to what would be considered keywords
and what would be built-in functions.
The list of keywords can be found (and overloaded) in the variable
$Syntax::Highlight::Perl::Improved::keyword_list_re as a pre-
compiled regular expression.
Builtin_Function
A Perl built-in function, called as a function (ie, using
parentheses).
The list of built-in functions can be found (and overloaded) in the
variable $Syntax::Highlight::Perl::Improved::builtin_list_re as a
pre-compiled regular expression.
Builtin_Operator
A Perl built-in function, called as a list or unary operator (ie,
without using parentheses).
The list of built-in functions can be found (and overloaded) in the
variable $Syntax::Highlight::Perl::Improved::builtin_list_re as a
pre-compiled regular expression.
Operator
A Perl operator.
The list of operators can be found (and overloaded) in the variable
$Syntax::Highlight::Perl::Improved::operator_list_re as a pre-
compiled regular expression.
Bareword
A bareword. This can be user-defined subroutine called without
parentheses, a typeglob used without an asterisk (*), or just a
plain old bareword.
Package
The name of a package or pragmatic module.
Note that this does not apply to the package portion of a fully
qualified variable name.
Number
A numeric literal.
Symbol
A symbol (ie, non-operator punctuation).
CodeTerm
The special tokens that signal the end of executable code and the
begining of the DATA section. Specifically, '"__END__"' and
'"__DATA__"'.
DATA
Anything in the DATA section (see "CodeTerm").
PROCEDURAL vs. OBJECT ORIENTEDSyntax::Highlight::Perl::Improved uses OO method-calls internally (and
actually defines a Default Object that is used when the functions are
invoked procedurally) so you will not gain anything (efficiency-wise)
by using the procedural interface. It is just a matter of style.
It is actually recommended that you use the OO interface, as this
allows you to instantiate multiple, concurrent-yet-separate formatters.
Though I cannot think of why you would need multiple formatters
instantiated. :-)
One point to note: the "new()" method uses the Default Object to
initialize new objects. This means that any changes to the state of
the Default Object (including Format definitions) made by using the
procedural interface will be reflected in any subsequently created
objects. This can be useful in some cases (eg, call "set_format()"
procedurally just before creating a batch of new objects to define
default Formats for them all) but will most likely lead to trouble.
METHODS
new PACKAGE
new OBJECT
Creates a new object. If called on an existing object, creates a
new copy of that object (which is thenceforth totally separate from
the original).
reset
Resets the object's internal state. This breaks out of strings and
here-docs, ends PODs, resets the line-count, and otherwise gets the
object back into a "normal" state to begin processing a new stream.
Note that this does not reset any user options (including formats
and format stability).
unstable EXPR
unstable
Returns true if the formatter is in unstable mode.
If called with a non-zero number, puts the formatter into unstable
formatting mode.
In unstable mode, it is assumed that formatting is not persistent
one token to the next and that each token must be explicitly
formatted.
in_heredoc
Returns true if the next string to be formatted will be inside a
Here-Document.
in_string
Returns true if the next string to be formatted will be inside a
multi-line string.
in_pod
Returns true if the formatter would consider the next string passed
to it as begin within a POD structure. This is false immediately
before any POD instigators ("=pod", "=head1", "=item", etc), true
immediately after an instigator, throughout the POD and immediately
before the POD terminator ("=cut"), and false immediately after the
POD terminator.
was_pod
Returns true if the last line of the string just formatted was part
of a POD structure. This includes the "/^=\w+/" POD instigators
and terminators.
in_data
Returns true if the next string to be formatted will be inside the
DATA section (ie, follows a "__DATA__" or "__END__" tag).
line_count
Returns the number of lines processed by the formatter.
substitutions
Returns a reference to the substitution table used. The
substitution table is a hash whose keys are the strings to be
replaced, and whose values are what to replace them with.
define_substitution HASH_REF
define_substitution LIST
Allows user to define certain characters that will be substituted
before formatting is done (but after they have been processed for
meaning).
If the first parameter is a reference to a hash, the formatter will
replace it's own hash with the given one, and subsequent changes to
the hash outside the formatter will be reflected.
Otherwise, it will copy the arguments passed into it's own hash,
and any substitutions already defined (but not in the parameter
list) will be preserved. (ie, the new substitutions will be added,
without destroying what was there already.)
set_start_format HASH_REF
set_start_format LIST
Given either a list of keys/values, or a reference to a hash of
keys/values, copy them into the object's Formats list.
set_end_format HASH_REF
set_end_format LIST
Given either a list of keys/values, or a reference to a hash of
keys/values, copy them into the object's Formats list.
set_format LIST
Sets the formatting string for one or more formats.
You should pass a list of keys/values where the keys are the format
names and the values are references to arrays containing the
starting and ending formatting strings (in that order) for that
format.
get_start_format LIST
Retrieve the string that is inserted to begin a given format type
(starting format string).
The names are looked for in the following order:
First: Prefer the names joined by underscore, from most general to
least. For example, given ("Variable", "Scalar"): "Variable" then
"Variable_Scalar".
Second: Then try each name singly, in reverse order. For example,
"Scalar" then "Variable".
See "FORMAT TYPES" for more information.
get_end_format LIST
Retrieve the string that is inserted to end a given format type
(ending format string).
get_format_names_list
Returns a list of the names of all the Formats defined.
get_start_format_values_list
Returns a list of the values of all the start Formats defined (in
the same order as the names returned by "get_format_names_list()").
get_end_format_values_list
Returns a list of the values of all the end Formats defined (in the
same order as the names returned by "get_format_names_list()").
format_string LIST
Formats one or more strings of Perl code. If no strings are
specified, defaults to $_. Returns the list of formatted strings
(or the first string formatted if called in scalar context).
Note: The end of the string is considered to be the end of a line,
regardless of whether or not there is a trailing line-break (but
trailing line-breaks will not cause an extra, empty line).
Another Note: The function actually uses $/ to determine line-
breaks, unless $/ is set to "\n" (newline). If $/ is "\n", then it
looks for the first match of "m/\r?\n|\n?\r/" in the string and
uses that to determine line-breaks. This is to make it easy to
handle non-unix text. Whatever characters it ends up using as
line-breaks are preserved.
format_token TOKEN, LIST
Returns TOKEN wrapped in the start and end Formats corresponding to
LIST (as would be returned by "get_start_format( LIST )" and
"get_end_format( LIST )", respectively).
No syntax checking is done on TOKEN but substitutions defined with
"define_substitution()" are performed.
KNOWN ISSUES or LIMITATIONS
· Barewords used as keys to a hash are formatted as strings. This is
Good. They should not be, however, if they are not the only thing
within the curly braces. That can be fixed.
· This version does not handle formats (see perlform(1)) very well.
It treats them as Here-Documents and ignores the rules for comment
lines, as well as the fact that picture lines are not supposed to
be interpolated. Thus, your picture lines will look strange with
the '@'s being formatted as array variables (albeit, invalid ones).
Ideally, it would also treat value lines as normal Perl code and
format accordingly. I think I'll get to the comment lines and non-
interpolating picture lines first. If/When I do get this fixed, I
will most likely add a format type of 'Format' or something, so
that they can be formatted differently, if so desired.
· This version does not handle Regular Expression significant
characters. It simply treats Regular Expressions as interpolated
strings.
· User-defined subroutines, called without parentheses, are formatted
as barewords. This is because there is no way to tell them apart
from barewords without parsing the code, and would require us to go
as far as perl does when doing the "-c" check (ie, executing BEGIN
and END blocks and the like). That's not going to happen.
· If you are indexing (subscripting) an array or hash, the formatter
tries to figure out the "real" variable class by looking at how you
index the variable. However, if you do something funky (but legal
in Perl) and put line-breaks or comments between the variable class
character ($) and your identifier, the formatter will get confused
and treat your variable as a scalar. Until it finds the index
character. Then it will format the scalar class character ($) as a
scalar and your identifier as the "correct" class.
· If you put a line-break between your variable identifier and it's
indexing character (see above), which is also legal in Perl, the
formatter will never find it and treat your variable as a scalar.
· If you put a line-break between a bareword hash-subscript and the
hash variable, or between a bareword and its associated "=>"
operator, the bareword will not be formatted correctly (as a
string). (Noticing a pattern here?)
BUGS
Bug reports are always welcome. Email me at b<davidcyl@cpan.org>.
AUTHOR
David C.Y. Liu b<davidcyl@cpan.org>
based on code by Cory Johns darkness@yossman.net
Copyright (c) 2004 David C.Y. Liu. This library is free software; you
can redistribute and/or modify it under the same conditions as Perl
itself.
TO DO
Note: This is Cory John's todo list, not mine. Currently none of these
features are planned for the near future.
1. Improve handling of regular expressions. Add support for regexp-
special characters. Recognize the /e option to the substitution
operator (maybe).
2. Improve handling of formats. Don't treat format definitions as
interpolating. Handle format-comments. Possibly format value
lines as normal Perl code.
3. Create in-memory deep-copy routine to replace "eval(Data::Dumper)"
deep-copy.
4. Generalize state transitions ("reset()" and, in the future,
"copy_state()") to use non-hard-coded keys and values for state
variables. Probably will extrapolate them into an overloadable
hash, and use the aforementioned deep-copy to assign them.
5. Create a method to save or copy states between objects
("copy_state()"). Would be useful for using this module in an
editor.
6. Add support for greater-than-one length special characters.
Specifically, octal, hexidecimal, and control character codes. For
example, "\644", "\x1a4" or "\c[".
REVISIONS
05-03-2004 David C.Y. Liu (Version 1.01)
· Added 'our' to the keywords list.
· Fixed bug that prevented interpolation inside qq() quotes.
· Renamed to Syntax::Highlight::Perl::Improved.
04-04-2001 Cory Johns
· Fixed problem with special characters not formatting inside of
Here-Documents.
· Fixed bug causing hash variables to format inside of Here-
Documents.
03-30-2001 Cory Johns
· Fixed bug where quote-terminators were checked for inside of Here-
Documents.
03-29-2001 Cory Johns
· Moved token processing tests from _format_line() into
_process_token() (where they should've been all along), generally
making _format_line() more logical. Contemplating extrapolating
the tokenizing and token loop into its own subroutine to avoid all
the recursive calls.
· Fixed bug that caused special characters to be recognized outside
of strings.
· Added $VERSION variable.
· Added support for different types of literal numbers: floating
point, exponential notation (eg: 1.3e10), hexidecimal, and
underscore-separated.
· Added the "CodeTerm" and "DATA" Formats.
03-27-2001 Cory Johns
· Added was_pod() and updated the documentation for in_pod().
03-20-2001 Cory Johns
· Added support for Perl formats (ie, `"format = ..."').
POD ERRORS
Hey! The above document had some coding errors, which are explained
below:
Around line 47:
You forgot a '=back' before '=head2'
Around line 102:
=back without =over
perl v5.14.02004-05-Syntax::Highlight::Perl::Improved(3)
