Module: VSql::Formatter

Extended by:
Formatter
Included in:
Formatter
Defined in:
lib/formatter.rb

Constant Summary collapse

DEFAULT_FORMATTER = 
lambda { |n|
  n.pieces.map { |p|
    p.is_a?(String) ? p : format_node(p)
  }.join
}
NODE_FORMATTERS = 
{
  SelectExpression => lambda { |n|
    formatted_expr = format_node(n.elements[0])
    if n.alias_node
      expr_alias = n.alias_node.text_value
      [formatted_expr, " AS ", quote_alias_if_needed(expr_alias)].join
    else
      formatted_expr
    end
  },
  SelectStatement => lambda { |n|
    statements = n.match(SelectExpression, Query)
    "\nSELECT\n" + eager_indent(statements.map { |s| format_node(s) }.join(",\n"))
  },
  LimitStatement => lambda { |n|
    "\nLIMIT" + n.elements[1..-1].map(&:text_value).join
  },
  WhereStatement  => lambda { |n|
    exprs = n.elements.select {|e| e.is_a?(Expression) }
    "\nWHERE " + indent(exprs.map {|e| DEFAULT_FORMATTER[e] }.join)
  },
  FromStatement   => lambda { |n|
    expressions = n.match(FromExpression, Query)
    "\nFROM " + indent(expressions.map {|e| format_node(e) }.join("\n"))
  },
  JoinStatement   => lambda { |n|
    join_keyword = n.match(JoinKeyword, Query)[0]
    from, criteria = n.elements.select {|e| e.is_a?(Expression) }
    ["\n",
     join_keyword.text_value.upcase,
     " ",
     indent(format_node(from)),
     " ON ",
     indent(format_node(criteria))].join
  },
  OrderByStatement   => lambda { |n|
    exprs = n.elements.select {|e| e.is_a?(OrderByExpression) }
    "\nORDER BY " + indent(exprs.map {|e| DEFAULT_FORMATTER[e] }.join)
  }
}
FORMATTERS = 
Hash.new(DEFAULT_FORMATTER).update(NODE_FORMATTERS)

Instance Method Summary collapse

Instance Method Details

#eager_indent(value, amount = 2) ⇒ Object 



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# File 'lib/formatter.rb', line 12

def eager_indent(value, amount = 2)
  indent(value, amount, true)
end

#format(node) ⇒ Object 



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# File 'lib/formatter.rb', line 77

def format(node)
  format_node(node).split("\n").map(&:rstrip).join("\n").strip + "\n"
end

#format_node(node) ⇒ Object 



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# File 'lib/formatter.rb', line 73

def format_node(node)
  FORMATTERS[node.class][node]
end

#indent(value, amount = 2, first_line = false) ⇒ Object 



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# File 'lib/formatter.rb', line 7

def indent(value, amount = 2, first_line = false)
  spacer = (" " * amount)
  (first_line ? spacer : "") + value.gsub("\n", "\n#{spacer}")
end

#quote_alias_if_needed(a) ⇒ Object 



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# File 'lib/formatter.rb', line 16

def quote_alias_if_needed(a)
  if a.match(/[^a-z0-9_]/)
    '"' + a + '"'
  else
    a
  end
end