Class: EBNF::Base
- Inherits:
-
Object
- Object
- EBNF::Base
- Defined in:
- lib/ebnf/base.rb
Instance Attribute Summary collapse
-
#ast ⇒ Array<Rule>
readonly
Abstract syntax tree from parse.
-
#errors ⇒ Array<String>
Grammar errors, or errors found genering parse tables.
Attributes included from LL1
#branch, #cleanup, #first, #follow, #pass, #start, #terminals
Instance Method Summary collapse
-
#debug(*args, **options) ⇒ Object
Progress output when debugging.
- #depth ⇒ Object
- #dup ⇒ Object
-
#each(kind) {|rule| ... } ⇒ Object
Iterate over each rule or terminal, except empty.
-
#error(*args, **options) ⇒ Object
Error output.
-
#find_rule(sym) ⇒ Rule
Find a rule given a symbol.
-
#initialize(input, format: :ebnf, **options) ⇒ Base
constructor
Parse the string or file input generating an abstract syntax tree in S-Expressions (similar to SPARQL SSE).
-
#progress(*args, **options) ⇒ Object
Progress output, less than debugging.
-
#renumber! ⇒ Object
Renumber, rule identifiers.
-
#to_html(format: :ebnf, validate: false) ⇒ String
Output formatted EBNF as HTML.
-
#to_ruby(output = $stdout, grammarFile: nil, mod_name: 'Meta', **options) ⇒ Object
Output Ruby parser files.
-
#to_s(format: :ebnf) ⇒ String
Output formatted EBNF.
-
#to_sxp ⇒ String
Write out parsed syntax string as an S-Expression.
-
#to_ttl(prefix = nil, ns = "http://example.org/") ⇒ String
Write out syntax tree as Turtle.
-
#valid? ⇒ Boolean
Is the grammar valid?.
-
#validate! ⇒ Object
Validate the grammar.
Methods included from PEG
Methods included from Native
#alt, #diff, #eachRule, #expression, #postfix, #primary, #ruleParts, #seq, #terminal
Methods included from LL1
#build_tables, #first_follow, #outputTable, #to_ruby_ll1
Methods included from BNF
Constructor Details
#initialize(input, format: :ebnf, **options) ⇒ Base
Parse the string or file input generating an abstract syntax tree in S-Expressions (similar to SPARQL SSE)
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# File 'lib/ebnf/base.rb', line 112 def initialize(input, format: :ebnf, **) @options = .dup @lineno, @depth, @errors = 1, 0, [] @ast = [] input = input.respond_to?(:read) ? input.read : input.to_s case format when :abnf abnf = ABNF.new(input, **) @ast = abnf.ast when :ebnf ebnf = Parser.new(input, **) @ast = ebnf.ast when :isoebnf iso = ISOEBNF.new(input, **) @ast = iso.ast when :native terminals = false scanner = StringScanner.new(input) eachRule(scanner) do |r| debug("rule string") {r.inspect} case r when /^@terminals/ # Switch mode to parsing terminals terminals = true rule = Rule.new(nil, nil, nil, kind: :terminals, ebnf: self) @ast << rule when /^@pass\s*(.*)$/m expr = expression($1).first rule = Rule.new(nil, nil, expr, kind: :pass, ebnf: self) rule.orig = expr @ast << rule else rule = depth {ruleParts(r)} rule.kind = :terminal if terminals # Override after we've parsed @terminals rule.orig = r @ast << rule end end when :sxp require 'sxp' unless defined?(SXP) @ast = SXP::Reader::Basic.read(input).map {|e| Rule.from_sxp(e)} else raise "unknown input format #{format.inspect}" end validate! if @options[:validate] end |
Instance Attribute Details
#ast ⇒ Array<Rule> (readonly)
Abstract syntax tree from parse
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# File 'lib/ebnf/base.rb', line 93 def ast @ast end |
#errors ⇒ Array<String>
Grammar errors, or errors found genering parse tables
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# File 'lib/ebnf/base.rb', line 98 def errors @errors end |
Instance Method Details
#debug(node, message) ⇒ Object #debug(message) ⇒ Object
Progress output when debugging
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# File 'lib/ebnf/base.rb', line 344 def debug(*args, **) return unless @options[:debug] depth = [:depth] || @depth args << yield if block_given? = "#{args.join(': ')}" str = "[#{@lineno}]#{' ' * depth}#{}" @options[:debug] << str if @options[:debug].is_a?(Array) $stderr.puts(str) if @options[:debug] == true end |
#depth ⇒ Object
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# File 'lib/ebnf/base.rb', line 304 def depth @depth += 1 ret = yield @depth -= 1 ret end |
#dup ⇒ Object
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# File 'lib/ebnf/base.rb', line 290 def dup new_obj = super new_obj.instance_variable_set(:@ast, @ast.dup) new_obj end |
#each(kind) {|rule| ... } ⇒ Object
Iterate over each rule or terminal, except empty
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# File 'lib/ebnf/base.rb', line 198 def each(kind, &block) ast.each {|r| block.call(r) if r.kind == kind && r.sym != :_empty} end |
#error(*args, **options) ⇒ Object
Error output
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# File 'lib/ebnf/base.rb', line 323 def error(*args, **) depth = [:depth] || @depth args << yield if block_given? = "#{args.join(': ')}" @errors << str = "[#{@lineno}]#{' ' * depth}#{}" @options[:debug] << str if @options[:debug].is_a?(Array) $stderr.puts(str) end |
#find_rule(sym) ⇒ Rule
Find a rule given a symbol
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# File 'lib/ebnf/base.rb', line 300 def find_rule(sym) (@find ||= {})[sym] ||= ast.detect {|r| r.sym == sym} end |
#progress(*args, **options) ⇒ Object
Progress output, less than debugging
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# File 'lib/ebnf/base.rb', line 312 def progress(*args, **) return unless @options[:progress] || @options[:debug] depth = [:depth] || @depth args << yield if block_given? = "#{args.join(': ')}" str = "[#{@lineno}]#{' ' * depth}#{}" @options[:debug] << str if @options[:debug].is_a?(Array) $stderr.puts(str) if @options[:progress] || @options[:debug] == true end |
#renumber! ⇒ Object
Renumber, rule identifiers
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# File 'lib/ebnf/base.rb', line 260 def renumber! ast.each_with_index do |rule, index| rule.id = (index + 1).to_s end end |
#to_html(format: :ebnf, validate: false) ⇒ String
Output formatted EBNF as HTML
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# File 'lib/ebnf/base.rb', line 225 def to_html(format: :ebnf, validate: false) Writer.html(*ast, format: format, validate: validate) end |
#to_ruby(output = $stdout, grammarFile: nil, mod_name: 'Meta', **options) ⇒ Object
Output Ruby parser files
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# File 'lib/ebnf/base.rb', line 235 def to_ruby(output = $stdout, grammarFile: nil, mod_name: 'Meta', **) unless output == $stdout output.puts "# This file is automatically generated by ebnf version #{EBNF::VERSION}" output.puts "# Derived from #{grammarFile}" if grammarFile unless self.errors.empty? output.puts "# Note, grammar has errors, may need to be resolved manually:" #output.puts "# #{pp.conflicts.map{|c| c.join("\n# ")}.join("\n# ")}" end output.puts "module #{mod_name}" output.puts " START = #{self.start.inspect}\n" if self.start end # Either output LL(1) BRANCH tables or rules for PEG parsing if ast.first.first to_ruby_ll1(output) else to_ruby_peg(output) end unless output == $stdout output.puts "end" end end |
#to_s(format: :ebnf) ⇒ String
Output formatted EBNF
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# File 'lib/ebnf/base.rb', line 215 def to_s(format: :ebnf) Writer.string(*ast, format: format) end |
#to_sxp ⇒ String
Write out parsed syntax string as an S-Expression
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# File 'lib/ebnf/base.rb', line 205 def to_sxp require 'sxp' unless defined?(SXP) SXP::Generator.string(ast.map(&:for_sxp)) end |
#to_ttl(prefix = nil, ns = "http://example.org/") ⇒ String
Write out syntax tree as Turtle
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# File 'lib/ebnf/base.rb', line 271 def to_ttl(prefix = nil, ns = "http://example.org/") unless ast.empty? [ "@prefix dc: <http://purl.org/dc/terms/>.", "@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.", "@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.", ("@prefix #{prefix}: <#{ns}>." if prefix), "@prefix : <#{ns}>.", "@prefix re: <http://www.w3.org/2000/10/swap/grammar/regex#>.", "@prefix g: <http://www.w3.org/2000/10/swap/grammar/ebnf#>.", "", ":language rdfs:isDefinedBy <>; g:start :#{ast.first.id}.", "", ].compact end.join("\n") + ast.map(&:to_ttl).join("\n") end |
#valid? ⇒ Boolean
Is the grammar valid?
Uses ‘#validate!` and catches `RangeError`
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# File 'lib/ebnf/base.rb', line 187 def valid? validate! true rescue SyntaxError false end |
#validate! ⇒ Object
Validate the grammar.
Makes sure that rules reference either strings or other defined rules.
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# File 'lib/ebnf/base.rb', line 170 def validate! ast.each do |rule| begin rule.validate!(@ast) rescue SyntaxError => e error("In rule #{rule.sym}: #{e.}") end end raise SyntaxError, errors.join("\n") unless errors.empty? end |