NAME¶
HTML::Mason::Compiler - Compile Mason component source
VERSION¶
version 1.54
SYNOPSIS¶
package My::Funky::Compiler;
use base qw(HTML::Mason::Compiler);
DESCRIPTION¶
The compiler starts the compilation process by calling its lexer's
"lex" method and passing itself as the "compiler"
parameter. The lexer then calls various methods in the compiler as it parses
the component source.
PARAMETERS TO THE new() CONSTRUCTOR¶
- allow_globals
- List of variable names, complete with prefix ("$@%"), that you
intend to use as globals in components. Normally global variables are
forbidden by "strict", but any variable mentioned in this list
is granted a reprieve via a "use vars" statement. For example:
allow_globals => [qw($DBH %session)]
In a mod_perl environment, $r (the request object) is automatically added to
this list.
- default_escape_flags
- Escape flags to apply to all <% %> expressions by default. The
current valid flags are
h - escape for HTML ('<' => '<', etc.)
u - escape for URL (':' => '%3A', etc.)
The developer can override default escape flags on a per-expression basis;
see the escaping expressions section of the developer's manual.
If you want to set multiple flags as the default, this should be
given as a reference to an array of flags.
- enable_autoflush
- True or false, default is true. Indicates whether components are compiled
with support for autoflush. The component can be compiled to a more
efficient form if it does not have to check for autoflush mode, so you
should set this to 0 if you can.
- lexer
- The Lexer object to associate with this Compiler. By default a new object
of class lexer_class will be created.
- lexer_class
- The class to use when creating a lexer. Defaults to
HTML::Mason::Lexer.
- preprocess
- Sub reference that is called to preprocess each component before the
compiler does it's magic. The sub is called with a single parameter, a
scalar reference to the script. The sub is expected to process the script
in-place. This is one way to extend the HTML::Mason syntax with new tags,
etc., although a much more flexible way is to subclass the Lexer or
Compiler class. See also postprocess_text and postprocess_perl.
- postprocess_text
- Sub reference that is called to postprocess the text portion of a compiled
component, just before it is assembled into its final subroutine form. The
sub is called with a single parameter, a scalar reference to the text
portion of the component. The sub is expected to process the string
in-place. See also preprocess and postprocess_perl.
- postprocess_perl
- Sub reference that is called to postprocess the Perl portion of a compiled
component, just before it is assembled into its final subroutine form. The
sub is called with a single parameter, a scalar reference to the Perl
portion of the component. The sub is expected to process the string
in-place. See also preprocess and postprocess_text.
- use_source_line_numbers
- True or false, default is true. Indicates whether component line numbers
that appear in error messages, stack traces, etc. are in terms of the
source file instead of the object file. Mason does this by inserting
'#line' directives into compiled components. While source line numbers are
more immediately helpful, object file line numbers may be more appropriate
for in-depth debugging sessions.
ACCESSOR METHODS¶
All of the above properties have read-only accessor methods of the same name.
You cannot change any property of a compiler after it has been created - among
other things, this would potentially invalidate any existing cached component
objects or object files. Your best bet is to create different compiler objects
and load them into different interpreters.
METHODS¶
There are several methods besides the compilation callbacks below that a
Compiler subclass needs to implement.
- compile(...)
- This method has several parameters:
- •
- comp_source (required)
Either a scalar or reference to a scalar containing the component
source.
- •
- name (required)
The name of the component. This should be the filename of the component if
it is file-based, or some other clear identifier of the component
source.
- •
- comp_path (required)
This should be the component's path.
- •
- fh (optional)
If this is given then the output of the compiler will be sent directly to
this handle, rather than being buffered in memory. This is an optimization
to avoid memory usage.
- object_id
- This method should return a unique id for the given compiler object. This
is used by the interpreter when determining the object directory, for
example.
Compilation Callbacks¶
These are methods called by the Lexer while processing a component source. You
may wish to override some of these methods if you're implementing your own
custom Compiler class.
- start_component()
- This method is called by the Lexer when it starts processing a
component.
- end_component()
- This method is called by the Lexer when it finishes processing a
component.
- start_block(block_type => <string>)
- This method is called by the Lexer when it encounters an opening Mason
block tag like "<%perl>" or "<%args>". Its
main purpose is to keep track of the nesting of different kinds of blocks
within each other. The type of block ("init", "once",
etc.) is passed via the "block_type" parameter.
- end_block(block_type => <string>)
- This method is called by the Lexer when it encounters a closing Mason
block tag like "</%perl>" or "</%args>".
Like "start_block()", its main purpose is to help maintain
syntactic integrity.
- *_block(block => <string>, [ block_type => <string>
])
- Several compiler methods like "doc_block()",
"text_block()", and "raw_block()" are called by the
Lexer after "start_block()" when it encounters blocks of certain
types. These methods actually do the work of putting the body of a block
into the compiled data structure.
The methods that follow this pattern are "init_block()",
"perl_block()", "doc_block()",
"text_block()", and "raw_block()". The last method is
called for all "<%once>", "<%cleanup>",
"<%filter>", "<%init>",
"<%perl>", and "<%shared>" blocks.
- text(text => <string>)
- Inserts the text contained in a "text" parameter into the
component for verbatim output.
This is called when the lexer finds plain text in a component.
- variable_declaration( type => <string>, name =>
<string>, default => <string> )
- Inserts a variable declaration from the "<%args>" section
into the component.
The type will be either "$", "@", or "%",
indicating a scalar, array, or hash. The name is the variable name without
the leading sigil. The default is everything found after the first
"=>" on an "<%args>" block line, and may
include a comment.
- key_value_pair(block_type => <string>, key => <string>,
value => <string>)
- Inserts a key-value pair from a "<%flags>" or
"<%attr>" section into the component.
The "block_type" parameter will be either "flags" or
"attr".
- start_named_block(block_type => <string>, name =>
<name>)
- Analogous to item_start_block, but starts a "named" block
("<%method>" or "<%def>").
- end_named_block()
- Called by the Lexer to end a "named" block.
- substitution(substitution => <string>, escape =>
<string>)
- Called by the Lexer when it encounters a substitution tag ("<% ...
%>").
The value of the "escape" parameter will be everything found after
the pipe (|) in the substitution tag, and may be more than one character
such as "nh".
- component_call(call => <string>)
- Called by the Lexer when it encounters a component call tag without
embedded content ("<& ... &>").
The "call" parameter contains the entire contents of the tag.
- component_content_call(call => <string>)
- Called by the Lexer when it encounters a component call tag with embedded
content ("<&| ... &>").
- component_content_call_end()
- Called by the Lexer when it encounters an ending tag for a component call
with content ("</&>"). Note that there is no
corresponding "component_call_end()" method for component calls
without content, because these calls don't have ending tags.
- perl_line(line => <string>)
- Called by the Lexer when it encounters a "%"-line.
SUBCLASSING¶
We recommend that any parameters you add to Compiler be read-only, because the
compiler object_id is only computed once on creation and would not reflect any
changes to Lexer parameters.
SEE ALSO¶
Mason
AUTHORS¶
- •
- Jonathan Swartz <swartz@pobox.com>
- •
- Dave Rolsky <autarch@urth.org>
- •
- Ken Williams <ken@mathforum.org>
COPYRIGHT AND LICENSE¶
This software is copyright (c) 2012 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under the same
terms as the Perl 5 programming language system itself.