class Html2haml::HTML::ERB

A class for converting ERB code into a format that's easier for the {Html2haml::HTML} Nokogiri-based parser to understand.

Uses [Erubis](www.kuwata-lab.com/erubis)‘s extensible parsing powers to parse the ERB in a reliable way, and [ruby_parser](parsetree.rubyforge.org/)’s Ruby knowledge to figure out whether a given chunk of Ruby code starts a block or not.

The ERB tags are converted to HTML tags in the following way. `<% … %>` is converted into `<haml_silent> … </haml_silent>`. `<%= … %>` is converted into `<haml_loud> … </haml_loud>`. `<%== … %>` is converted into `<haml_loud raw=raw> … </haml_loud>`. Finally, if either of these opens a Ruby block, `<haml_block> … </haml_block>` will wrap the entire contents of the block - that is, everything that should be indented beneath the previous silent or loud tag.

Public Class Methods

compile(template) click to toggle source

Compiles an ERB template into a HTML document containing `haml_*` tags.

@param template [String] The ERB template @return [String] The output document @see Html2haml::HTML::ERB

# File lib/html2haml/html/erb.rb, line 28
def self.compile(template)
  new(template).src
end

Public Instance Methods

add_expr_debug(src, code) click to toggle source

`html2haml` doesn't support debugging expressions.

# File lib/html2haml/html/erb.rb, line 81
def add_expr_debug(src, code)
  raise Haml::Error.new("html2haml doesn't support debugging expressions.")
end
add_expr_escaped(src, code) click to toggle source
# File lib/html2haml/html/erb.rb, line 76
def add_expr_escaped(src, code)
  src << "<haml_loud raw=raw>" << h(code) << "</haml_loud>"
end
add_expr_literal(src, code) click to toggle source

Concatenates a Ruby expression that's printed to the document onto the source buffer. This uses the `<haml:silent>` tag, and may open a Ruby block with the `<haml:block>` tag. An expression never closes a block.

@param src [String] The source buffer @param code [String] The Ruby expression to add to the buffer

# File lib/html2haml/html/erb.rb, line 71
def add_expr_literal(src, code)
  src << '<haml_loud>' << h(code) << '</haml_loud>'
  src << '<haml_block>' if block_opener?(code)
end
add_postamble(src) click to toggle source

The ERB-to-Hamlized-HTML conversion has no postamble.

# File lib/html2haml/html/erb.rb, line 36
def add_postamble(src); end
add_preamble(src) click to toggle source

The ERB-to-Hamlized-HTML conversion has no preamble.

# File lib/html2haml/html/erb.rb, line 33
def add_preamble(src); end
add_stmt(src, code) click to toggle source

Concatenates a silent Ruby statement onto the source buffer. This uses the `<haml_silent>` tag, and may close and/or open a Ruby block with the `<haml_block>` tag.

In particular, a block is closed if this statement is some form of `end`, opened if it's a block opener like `do`, `if`, or `begin`, and both closed and opened if it's a mid-block keyword like `else` or `when`.

@param src [String] The source buffer @param code [String] The Ruby statement to add to the buffer

# File lib/html2haml/html/erb.rb, line 57
def add_stmt(src, code)
  src << '</haml_block>' if block_closer?(code) || mid_block?(code)
  src << '<haml_silent>' << h(code) << '</haml_silent>' unless code.strip == "end"
  src << '<haml_block>' if block_opener?(code) || mid_block?(code)
end
add_text(src, text) click to toggle source

Concatenates the text onto the source buffer.

@param src [String] The source buffer @param text [String] The raw text to add to the buffer

# File lib/html2haml/html/erb.rb, line 42
def add_text(src, text)
  src << text
end

Private Instance Methods

block_closer?(code) click to toggle source

Checks if a string of Ruby code closes a block. This is always `end` followed optionally by some method calls.

@param code [String] Ruby code to check @return [Boolean]

# File lib/html2haml/html/erb.rb, line 135
def block_closer?(code)
  return unless has_code?(code)
  valid_ruby?("begin\n" + code)
end
block_opener?(code) click to toggle source

Checks if a string of Ruby code opens a block. This could either be something like `foo do |a|` or a keyword that requires a matching `end` like `if`, `begin`, or `case`.

@param code [String] Ruby code to check @return [Boolean]

# File lib/html2haml/html/erb.rb, line 124
def block_opener?(code)
  return unless has_code?(code)
  valid_ruby?(code + "\nend") ||
    valid_ruby?(code + "\nwhen foo\nend")
end
h(text) click to toggle source

HTML-escaped some text (in practice, always Ruby code). A utility method.

@param text [String] The text to escape @return [String] The escaped text

# File lib/html2haml/html/erb.rb, line 92
def h(text)
  CGI.escapeHTML(text)
end
has_code?(code) click to toggle source

Returns whether the code has any content This is used to test whether lines have been removed by erubis, such as comments

@param code [String] Ruby code to check @return [Boolean]

# File lib/html2haml/html/erb.rb, line 111
def has_code?(code)
  return false if code == "\n"
  return false if valid_ruby?(code) == nil
  true
end
mid_block?(code) click to toggle source

Checks if a string of Ruby code comes in the middle of a block. This could be a keyword like `else`, `rescue`, or `when`, or even `end` with a method call that takes a block.

@param code [String] Ruby code to check @return [Boolean]

# File lib/html2haml/html/erb.rb, line 146
def mid_block?(code)
  return unless has_code?(code)
  return if valid_ruby?(code)
  valid_ruby?("if foo\n#{code}\nend") || # else, elsif
    valid_ruby?("begin\n#{code}\nend") || # rescue, ensure
    valid_ruby?("case foo\n#{code}\nend") # when
end
valid_ruby?(code) click to toggle source

Returns whether the code is valid Ruby code on its own.

@param code [String] Ruby code to check @return [Boolean]

# File lib/html2haml/html/erb.rb, line 100
def valid_ruby?(code)
  RubyParser.new.parse(code)
rescue Racc::ParseError, RubyParser::SyntaxError
  false
end