Module: POECSS

Defined in:
lib/poe-css.rb,
lib/poe-css/parser.rb,
lib/poe-css/version.rb,
lib/poe-css/generator.rb,
lib/poe-css/simplifier.rb,
lib/poe-css/preprocessor.rb

Defined Under Namespace

Modules: Generator, Parser, Preprocessor, Simplifier Classes: Clause, CommandClause, MatchClause, ParseError, RGBColorSpec, SimpleClause

Constant Summary collapse

VERSION = 
'0.0.1'

Class Method Summary collapse

Class Method Details

.compile(input) ⇒ Object 



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# File 'lib/poe-css.rb', line 67

def compile(input)
  # Strip comments, which is anything after a # in any line. No
  # preprocessor or POE CSS syntax uses the #, and it doesn't appear in any
  # strings (it could, but no item has a # in it), so it's safe to
  # disregard all syntax when removing comments.
  input_without_comments = input.split("\n").map { |l| l.gsub(/#.*$/, '') }.join("\n")

  # Use the preprocessor to expand constants and macros.
  preprocessed_program = Preprocessor.compile(input_without_comments)

  # Hand the contents over to the main parser, which returns a list of Clauses.
  parsed_clauses = Parser.parse_input(preprocessed_program)

  # These Clauses, each of which can contain alternations (ORs) or nested
  # clauses, get transformed into SimpleClauses. A SimpleClause is just a
  # list of ANDed match clauses and a list of commands. The nesting and
  # alternations have been expanded. We also simplify clauses here to
  # minimize inputs into the next step as well as to collapse/minimize
  # duplicated match and command keys for speed/simplicity.
  expanded_clauses = expand_clauses(parsed_clauses).map { |r| Simplifier.simplify_clause(r) }.compact

  # SimpleClauses are then converted into a list of rules in else-if form,
  # the logical flow style used by PoE. The datatype is still SimpleClause,
  # but the clauses have all been transformed and expanded to meet the
  # else-if form (I call them rules to distinguish them conceptually from
  # clauses).
  else_ifed_rules = clauses_to_else_if_rules(expanded_clauses)

  # Finally, rules that will never be hit or contribute nothing to to final
  # result are deleted. This does not remove every useless clause but is
  # likely good enough to suffice.
  rules_without_dead_rules = rules_without_dead_rules(else_ifed_rules)

  # Finally, we hand the results to the generator, which outputs them in
  # PoE item filter format.
  Generator.generate_poe_rules(rules_without_dead_rules)
end