haml--haml/lib/haml/engine.rb

551 lines
17 KiB
Ruby

require File.dirname(__FILE__) + '/helpers'
require File.dirname(__FILE__) + '/buffer'
module Haml
# This is the class where all the parsing and processing of the HAML
# template is done. It can be directly used by the user by creating a
# new instance and calling to_html to render the template. For example:
#
# template = File.load('templates/really_cool_template.haml')
# haml_engine = Haml::Engine.new(template)
# output = haml_engine.to_html
# puts output
class Engine
# Allow access to the precompiled template
attr_reader :precompiled
# Allow reading and writing of the options hash
attr :options, true
# Designates an XHTML/XML element.
ELEMENT = '%'[0]
# Designates a <tt><div></tt> element with the given class.
DIV_CLASS = '.'[0]
# Designates a <tt><div></tt> element with the given id.
DIV_ID = '#'[0]
# Designates an XHTML/XML comment.
COMMENT = '/'[0]
# Designates an XHTML doctype.
DOCTYPE = '!'[0]
# Designates script, the result of which is output.
SCRIPT = '='[0]
# Designates script, the result of which is flattened and output.
FLAT_SCRIPT = '~'[0]
# Designates script which is run but not output.
SILENT_SCRIPT = '-'[0]
# When following SILENT_SCRIPT, designates a comment that is not output.
SILENT_COMMENT = '#'[0]
# Designates a non-parsed line.
ESCAPE = '\\'[0]
# Designates a non-parsed line. Not actually a character.
PLAIN_TEXT = -1
# Keeps track of the ASCII values of the characters that begin a
# specially-interpreted line.
SPECIAL_CHARACTERS = [
ELEMENT,
DIV_CLASS,
DIV_ID,
COMMENT,
DOCTYPE,
SCRIPT,
FLAT_SCRIPT,
SILENT_SCRIPT,
ESCAPE
]
# The value of the character that designates that a line is part
# of a multiline string.
MULTILINE_CHAR_VALUE = '|'[0]
# Characters that designate that a multiline string may be about
# to begin.
MULTILINE_STARTERS = SPECIAL_CHARACTERS - ["/"[0]]
# Keywords that appear in the middle of a Ruby block with lowered
# indentation. If a block has been started using indentation,
# lowering the indentation with one of these won't end the block.
# For example:
#
# - if foo
# %p yes!
# - else
# %p no!
#
# The block is ended after <tt>%p no!</tt>, because <tt>else</tt>
# is a member of this array.
MID_BLOCK_KEYWORDS = ['else', 'elsif', 'rescue', 'ensure', 'when']
# Creates a new instace of Haml::Engine to compile the given
# template string. See REFERENCE for available options.
#
#--
# When adding options, remember to add information about them
# to REFERENCE!
#++
#
def initialize(template, options = {})
@options = {
:suppress_eval => false,
:attr_wrapper => "'",
:locals => {}
}.merge options
@precompiled = @options[:precompiled]
@template = template #String
@to_close_stack = []
@output_tabs = 0
@template_tabs = 0
# This is the base tabulation of the currently active
# flattened block. -1 signifies that there is no such block.
@flat_spaces = -1
# Only do the first round of pre-compiling if we really need to.
# They might be passing in the precompiled string.
do_precompile if @precompiled.nil? && (@precompiled = String.new)
end
# Processes the template and returns the resulting (X)HTML code as
# a string.
def to_html(scope = Object.new, &block)
@scope_object = scope
@buffer = Haml::Buffer.new(@options)
local_assigns = @options[:locals]
# Get inside the view object's world
@scope_object.instance_eval do
# Set all the local assigns
local_assigns.each do |key,val|
self.class.send(:define_method, key) { val }
end
end
# Compile the @precompiled buffer
compile &block
# Return the result string
@buffer.buffer
end
private
#Precompile each line
def do_precompile
push_silent <<-END
def _haml_render
_hamlout = @haml_stack[-1]
_erbout = _hamlout.buffer
END
old_line = nil
old_index = nil
old_spaces = nil
old_tabs = nil
(@template + "\n\n").each_with_index do |line, index|
spaces, tabs = count_soft_tabs(line)
line = line.strip
if old_line
block_opened = tabs > old_tabs
suppress_render = handle_multiline(old_tabs, old_line, old_index)
if !suppress_render && old_spaces
line_empty = old_line.empty?
process_indent(old_tabs, old_line) unless line_empty
flat = @flat_spaces != -1
if flat
push_flat(old_line, old_spaces)
elsif !line_empty
process_line(old_line, old_index, block_opened)
end
end
end
old_line = line
old_index = index
old_spaces = spaces
old_tabs = tabs
end
# Close all the open tags
@template_tabs.times { close }
push_silent "end"
end
# Processes and deals with lowering indentation.
def process_indent(count, line)
if count <= @template_tabs && @template_tabs > 0
to_close = @template_tabs - count
to_close.times do |i|
offset = to_close - 1 - i
unless offset == 0 && mid_block_keyword?(line)
close
end
end
end
end
# Processes a single line of HAML.
#
# This method doesn't return anything; it simply processes the line and
# adds the appropriate code to <tt>@precompiled</tt>.
def process_line(line, index, block_opened)
case line[0]
when DIV_CLASS, DIV_ID
render_div(line, index)
when ELEMENT
render_tag(line, index)
when COMMENT
render_comment(line)
when SCRIPT
push_script(line[1..-1], false, block_opened, index)
when FLAT_SCRIPT
push_flat_script(line[1..-1], block_opened, index)
when SILENT_SCRIPT
sub_line = line[1..-1]
unless sub_line[0] == SILENT_COMMENT
push_silent(sub_line, index)
if block_opened && !mid_block_keyword?(line)
push_and_tabulate([:script])
end
end
when DOCTYPE
if line[0...3] == '!!!'
render_doctype(line)
else
push_text line
end
when ESCAPE
push_text line[1..-1]
else
push_text line
end
end
# Returns whether or not the line is a silent script line with one
# of Ruby's mid-block keywords.
def mid_block_keyword?(line)
line.length > 2 && line[0] == SILENT_SCRIPT && MID_BLOCK_KEYWORDS.include?(line[1..-1].split[0])
end
# Deals with all the logic of figuring out whether a given line is
# the beginning, continuation, or end of a multiline sequence.
#
# This returns whether or not the line should be
# rendered normally.
def handle_multiline(count, line, index)
# Multilines are denoting by ending with a `|` (124)
if is_multiline?(line) && @multiline_buffer
# A multiline string is active, and is being continued
@multiline_buffer += line[0...-1]
suppress_render = true
elsif is_multiline?(line) && (MULTILINE_STARTERS.include? line[0])
# A multiline string has just been activated, start adding the lines
@multiline_buffer = line[0...-1]
@multiline_count = count
@multiline_index = index
process_indent(count, line)
suppress_render = true
elsif @multiline_buffer
# A multiline string has just ended, make line into the result
process_line(@multiline_buffer, @multiline_index, count > @multiline_count)
@multiline_buffer = nil
suppress_render = false
end
return suppress_render
end
# Checks whether or not +line+ is in a multiline sequence.
def is_multiline?(line) # ' '[0] == 32
line && line.length > 1 && line[-1] == MULTILINE_CHAR_VALUE && line[-2] == 32
end
# Takes <tt>@precompiled</tt>, a string buffer of Ruby code, and
# evaluates it in the context of <tt>@scope_object</tt>, after preparing
# <tt>@scope_object</tt>. The code in <tt>@precompiled</tt> populates
# <tt>@buffer</tt> with the compiled XHTML code.
def compile(&block)
# Set the local variables pointing to the buffer
buffer = @buffer
@scope_object.extend Haml::Helpers
@scope_object.instance_eval do
@haml_stack ||= Array.new
@haml_stack.push(buffer)
class << self
attr :haml_lineno
end
end
begin
# Evaluate the buffer in the context of the scope object
@scope_object.instance_eval @precompiled
@scope_object._haml_render &block
rescue Exception => e
# Get information from the exception and format it so that
# Rails can understand it.
compile_error = e.message.scan(/\(eval\):([0-9]*):in `[-_a-zA-Z]*': compile error/)[0]
filename = "(haml)"
if @scope_object.methods.include? "haml_filename"
# For some reason that I can't figure out,
# @scope_object.methods.include? "haml_filename" && @scope_object.haml_filename
# is false when it shouldn't be. Nested if statements work, though.
if @scope_object.haml_filename
filename = "#{@scope_object.haml_filename}.haml"
end
end
lineno = @scope_object.haml_lineno
if compile_error
eval_line = compile_error[0].to_i
line_marker = @precompiled.split("\n")[0...eval_line].grep(/@haml_lineno = [0-9]*/)[-1]
lineno = line_marker.scan(/[0-9]+/)[0].to_i if line_marker
end
e.backtrace.unshift "#{filename}:#{lineno}"
raise e
end
# Get rid of the current buffer
@scope_object.instance_eval do
@haml_stack.pop
end
end
# Evaluates <tt>text</tt> in the context of <tt>@scope_object</tt>, but
# does not output the result.
def push_silent(text, index = nil)
if index
@precompiled << "@haml_lineno = #{index + 1}\n#{text}\n"
else
# Not really DRY, but probably faster
@precompiled << "#{text}\n"
end
end
# Adds <tt>text</tt> to <tt>@buffer</tt> with appropriate tabulation
# without parsing it.
def push_text(text)
@precompiled << "_hamlout.push_text(#{text.dump}, #{@output_tabs})\n"
end
# Adds +text+ to <tt>@buffer</tt> while flattening text.
def push_flat(text, spaces)
tabulation = spaces - @flat_spaces
@precompiled << "_hamlout.push_text(#{text.dump}, #{tabulation > -1 ? tabulation : 0}, true)\n"
end
# Causes <tt>text</tt> to be evaluated in the context of
# <tt>@scope_object</tt> and the result to be added to <tt>@buffer</tt>.
#
# If <tt>flattened</tt> is true, Haml::Helpers#find_and_flatten is run on
# the result before it is added to <tt>@buffer</tt>
def push_script(text, flattened, block_opened, index)
unless options[:suppress_eval]
push_silent("haml_temp = #{text}", index)
out = "haml_temp = _hamlout.push_script(haml_temp, #{@output_tabs}, #{flattened})\n"
if block_opened
push_and_tabulate([:loud, out])
else
@precompiled << out
end
end
end
# Causes <tt>text</tt> to be evaluated, and Haml::Helpers#find_and_flatten
# to be run on it afterwards.
def push_flat_script(text, block_opened, index)
unless text.empty?
push_script(text, true, block_opened, index)
else
start_flat(false)
end
end
# Closes the most recent item in <tt>@to_close_stack</tt>.
def close
tag, value = @to_close_stack.pop
case tag
when :script
close_block
when :comment
close_comment value
when :element
close_tag value
when :flat
close_flat value
when :loud
close_loud value
end
end
# Puts a line in <tt>@precompiled</tt> that will add the closing tag of
# the most recently opened tag.
def close_tag(tag)
@output_tabs -= 1
@template_tabs -= 1
@precompiled << "_hamlout.close_tag(#{tag.dump}, #{@output_tabs})\n"
end
# Closes a Ruby block.
def close_block
push_silent "end"
@template_tabs -= 1
end
# Closes a comment.
def close_comment(has_conditional)
@output_tabs -= 1
@template_tabs -= 1
push_silent "_hamlout.close_comment(#{has_conditional}, #{@output_tabs})"
end
# Closes a flattened section.
def close_flat(in_tag)
@flat_spaces = -1
if in_tag
close
else
push_silent('_hamlout.stop_flat')
@template_tabs -= 1
end
end
# Closes a loud Ruby block.
def close_loud(command)
push_silent "end"
@precompiled << command
@template_tabs -= 1
end
# Parses a line that will render as an XHTML tag, and adds the code that will
# render that tag to <tt>@precompiled</tt>.
def render_tag(line, index)
line.scan(/[%]([-:_a-zA-Z0-9]+)([-_a-zA-Z0-9\.\#]*)(\{.*\})?(\[.*\])?([=\/\~]?)?(.*)?/) do |tag_name, attributes, attributes_hash, object_ref, action, value|
value = value.to_s
case action
when '/'
atomic = true
when '=', '~'
parse = true
else
value = value.strip
end
flattened = (action == '~')
value_exists = !value.empty?
attributes_hash = "nil" unless attributes_hash
object_ref = "nil" unless object_ref
push_silent "_hamlout.open_tag(#{tag_name.inspect}, #{@output_tabs}, #{atomic.inspect}, #{value_exists.inspect}, #{attributes.inspect}, #{attributes_hash}, #{object_ref}, #{flattened.inspect})"
unless atomic
push_and_tabulate([:element, tag_name])
@output_tabs += 1
if value_exists
if parse
push_script(value, flattened, false, index)
else
push_text(value)
end
close
elsif flattened
start_flat(true)
end
end
end
end
# Renders a line that creates an XHTML tag and has an implicit div because of
# <tt>.</tt> or <tt>#</tt>.
def render_div(line, index)
render_tag('%div' + line, index)
end
# Renders an XHTML comment.
def render_comment(line)
conditional, content = line.scan(/\/(\[[a-zA-Z0-9 ]*\])?(.*)/)[0]
content = content.strip
try_one_line = !content.empty?
push_silent "_hamlout.open_comment(#{try_one_line}, #{conditional.inspect}, #{@output_tabs})"
@output_tabs += 1
push_and_tabulate([:comment, !conditional.nil?])
if try_one_line
push_text content
close
end
end
# Renders an XHTML doctype or XML shebang.
def render_doctype(line)
line = line[3..-1].lstrip.downcase
if line[0...3] == "xml"
encoding = line.split[1] || "utf-8"
wrapper = @options[:attr_wrapper]
doctype = "<?xml version=#{wrapper}1.0#{wrapper} encoding=#{wrapper}#{encoding}#{wrapper} ?>"
else
version, type = line.scan(/([0-9]\.[0-9])?[\s]*([a-zA-Z]*)/)[0]
if version == "1.1"
doctype = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">'
else
case type
when "strict"
doctype = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">'
when "frameset"
doctype = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">'
else
doctype = '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">'
end
end
end
push_text doctype
end
# Starts a flattened block.
def start_flat(in_tag)
# @flat_spaces is the number of indentations in the template
# that forms the base of the flattened area
if in_tag
@to_close_stack.push([:flat, true])
else
push_and_tabulate([:flat])
end
@flat_spaces = @template_tabs * 2
end
# Counts the tabulation of a line.
def count_soft_tabs(line)
spaces = line.index(/[^ ]/)
spaces ? [spaces, spaces/2] : []
end
# Pushes value onto <tt>@to_close_stack</tt> and increases
# <tt>@template_tabs</tt>.
def push_and_tabulate(value)
@to_close_stack.push(value)
@template_tabs += 1
end
end
end