Class: Grammar::Ruby

Inherits:
Object
  • Object
show all
Defined in:
lib/grammar/ruby.rb,
lib/grammar/ruby/code.rb

Direct Known Subclasses

Ruby2CExt, RubyCall

Defined Under Namespace

Classes: Code, CodeProxy, Var

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input_method = :[]) ⇒ Ruby

Returns a new instance of Ruby.



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# File 'lib/grammar/ruby.rb', line 74

def initialize(input_method=:[])
    @followed = 0
    @consumed = 0
    @output0 = Code::Primary.new("o")
    @output = @output0
    @output_init = nil
    @input0 = Code::Primary.new("i")
    @input = @input0
    @input_method = input_method
    @lookahead0 = Code::Primary.new("la")
    @lookahead = @lookahead0
    @lookahead_get = Code::Self.at(Code[0])
    @lookahead_set = Code::Self[Code[0]]
    @fail0 = Code::Primary.new("f")
    @fail = @fail0
    @failure_hard = lambda { |i, la, *expected|
        Code::Always.new(@fail[i, la, *expected])
    }
    @failure_break = proc { Code::Always.new(Code::Implicit.break) }
    @failure = @failure_hard
    @expected = []
    @assignments = []
    @constants = Hash.new { |h, object|
        code = Code[object]
        if code._immediate
            h[object] = code
        else
            h[object] = assign(code)
        end
    }
    @method_definitions = []
    @methods = {}
    @consume = true
    @void = nil
    @scope = nil
end

Class Method Details

.compile(gram, input_method = :[]) ⇒ Object

compile a grammar to a parser. The parser can be called with an input (#[] to get next element) and an output (#<< appends to it).



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# File 'lib/grammar/ruby.rb', line 9

def self.compile(gram, input_method=:[])
    code = new(input_method).dump(gram)
    #p(code)
    #code.lined
    eval(code.to_s).new
end

.dump(gram) ⇒ Object

dump the grammar to a Code object. #to_s get get Ruby code from it.



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# File 'lib/grammar/ruby.rb', line 17

def self.dump(gram)
    new.dump(gram)
end

Instance Method Details

#<<(item) ⇒ Object

appends to the engine’s output



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# File 'lib/grammar/ruby.rb', line 70

def <<(item)
    @output << item
end

#[](object, clone = false) ⇒ Object

convert a normal Ruby object to something that can be used in an action block. Set clone if a clone should be made everytime this is referenced.



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# File 'lib/grammar/ruby.rb', line 23

def [](object, clone=false)
    if clone
        case object
        when String,Bignum,Float
            Code::Primary.new(object.inspect)
        when Array,Hash
            object.empty? ? Code::Primary.new(object.inspect) :
                @constants[object].clone
        else
            code = @constants[object]
            code._immediate ? code : code.clone
        end
    else
        @constants[object]
    end
end

#alternation(gram1) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 272

def alternation(gram1) # :yield: engine
    failure = @failure
    @failure = nil
    if output_init = @output_init
        begin
            gram1[self]._and {
                @output_init ? @output._assign(@output_init) : Code::True
            }
        ensure
            failure1 = @failure
            output_init1 = @output_init
        end._or{
            @failure = failure
            @output_init = output_init
            code = yield(self)
            if !output_init1 and @output_init
                code = @output._assign(@output_init)._step(code)
            end
            code
        }
    else
        begin
            gram1[self]
        ensure
            failure1 = @failure
        end._or{
            @failure = failure
            yield(self)
        }
    end
ensure
    @failure = failure1 if failure1
end

#always ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 261

def always # :yield: engine
    Code::Always.new(yield(self))
end

#and(first, &second) ⇒ Object

replacement for ruby’s builtin “and”/“&&” operators



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# File 'lib/grammar/ruby.rb', line 54

def and(first, &second) # :yield:
    first._and(&second)
end

#any ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 240

def any
    @expected << Code["ANY"]
    consume(@lookahead)
end

#assign(code) ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 111

def assign(code)
    var = Code::Primary.new("@_#{@assignments.size}")
ensure
    @assignments << var._assign(code)
end

#backref(gram, &block) ⇒ Object

:yield: n[, engine]



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# File 'lib/grammar/ruby.rb', line 628

def backref(gram, &block) # :yield: n[, engine]
    raise("TODO")
end

#backtrack(gram, len = nil, &block) ⇒ Object

:yield: n[, engine]



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# File 'lib/grammar/ruby.rb', line 632

def backtrack(gram, len=nil, &block) # :yield: n[, engine]
    raise("TODO")
end

#call(inner = nil, &outer) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 386

def call(inner=nil, &outer) # :yield: engine
    @consume or return(inner ? recurse(inner, true, &outer) : outer[self])
    @methods[outer] or begin
        i = @method_definitions.size
        @method_definitions << nil
        name = "m#{i}"
        output = @output
        input = @input
        lookahead = @lookahead
        fail = @fail
        failure = @failure
        expected = @expected
        scope = @scope
        consume = @consume
        begin
            @output = @output0
            @input = @input0
            @lookahead = @lookahead0
            @scope = name
            @fail = @fail0
            @failure = nil
            @expected = []
            @consume = nil
            code = inner ? recurse(inner, true, &outer) : outer[self]
            @expected.clear if code._always
            @methods[outer] = [name,@expected]
            @fail = @fail0
            @failure = nil
            @expected = []
            @consume = true
            code = inner ? recurse(inner, true, &outer) : outer[self]
            @method_definitions[i] =
                code._and {
                    @lookahead_set._assign(@lookahead)._step(Code::True)
                }._def(
                    name,
                    @output,
                    @input,
                    @lookahead,
                    @fail
                )
        ensure
            @output = output
            @input = input
            @lookahead = lookahead
            @consume = consume
            @fail = fail
            @failure = failure
            @expected = expected
            @scope = scope
        end
    end
    name,expected = @methods[outer]
    output = @output || (@void ||= assign(
        Code[Class].new {
            Code::Def.new(:<<,
                [Code::Primary.new("other")],
                Code::Self)
        }.new
    ))
    call = Code::Self.method_missing(name, output, @input,
                                     @lookahead, @fail)._and {
        @lookahead._assign(@lookahead_get)._step(Code::True)
    }
    if expected.empty?
        Code::Always.new(call)
    else
        call._or{ @expected.concat(expected); failure() }
    end
    
end

#consume(matching, expected = nil) ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 212

def consume(matching, expected=nil)
    if @consume
        matching = matching._and {
            consume = @lookahead._assign(
                @input.method_missing(@input_method)
            )
            if @output
                consume = ((@output_init ? @output._assign(@output_init) : 
                                           @output) << @lookahead).
                          _step(consume)
            end
            consume._step(Code::True)
        }
    end
    matching._or{failure(expected)}
ensure
    if @consume
        @output_init = nil
        @failure = @failure_hard
        @consumed += 1
    end
end

#discard(gram) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 552

def discard(gram) # :yield: engine
    @consume or return(gram[self])
    output = @output
    consume = @consume
    @followed += 1 if block_given?
    begin
        @output = nil
        @consume = true
        gram[self]
    ensure
        @followed -= 1 if block_given?
        @output = output
        @consume = consume
    end._and {
        !block_given? ? Code::True :
        Code::Always.new(@output << yield(self))
    }
end

#dump(gram) ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 161

def dump(gram)
    scope = @scope
    @scope = "call"
    top = gram[self]
    @scope = scope
    CodeProxy.new(Code[Class].new(Code[Array]) { ||
        steps = []
        @assignments.each { |assignment|
            steps << assignment
        }
        steps << Code::Implicit.super(Code[1])
        steps = [Code::Steps.new(steps)._def(:initialize)] unless
            steps.empty?
        @method_definitions.each { |definition|
            steps << definition
        }
        steps << top._and {
            Code::Self.block_given?._and{
                Code::Implicit.yield(@lookahead)
            }._step(Code::True)
        }._def(:call,
            @output,
            @input,
            @lookahead._assign(@input.method_missing(@input_method)),
            @fail._assign(Code::Self.lambda { |i, la, *exp|
                exp = exp[0]
                Code::Implicit.raise(
                    Code["found: "].concat(la.inspect).
                        concat(Code[", expected: "]).
                        concat(exp.map{|e|e.inspect}.join(Code[", "]))
                )
            })
        )
        #steps << Code::Self.alias_method(Code[:call], Code[name])
        steps << Code::Self.alias_method(Code[:"[]"], Code[:call])
        Code::Steps.new(steps)
    })
end

#eof ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 234

def eof
    @lookahead._not._or{
        @expected << Code["EOF"]
        failure
    }
end

#failure(expected = nil) ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 200

def failure(expected=nil)
    @expected << self[expected] if expected
    if @failure
        begin
            @failure[@input, @lookahead, *@expected]
        ensure
            @expected = []
        end
    else
        Code::False
    end
end

#if(condition, yes, &no) ⇒ Object

replacement for ruby’s builtin “if”/“else”/“?”/“:” constructs



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# File 'lib/grammar/ruby.rb', line 66

def if(condition, yes, &no)
    condition._question(yes[], no[])
end

#match(pat) ⇒ Object 



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# File 'lib/grammar/ruby.rb', line 244

def match(pat)
    if Range===pat
        op = pat.exclude_end? ? :> : :>=
        @expected << Code[pat]
        consume(@lookahead._and{(self[pat.begin]<=@lookahead)._and{
            self[pat.end].__send__(op, @lookahead)
        }})
    else
        code = @constants[pat]
        @expected << code
        consume(if code._immediate
            code.equal?(@lookahead)
        else
            code===@lookahead
        end)
    end
end

#negative ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 338

def negative # :yield: engine
    consume = @consume
    @consume = nil
    failure = @failure
    @failure = nil
    begin
        yield(self)._not
    ensure
        @failure = failure
        @consume = consume
    end._or{
        @expected << Code["something else"]
        failure()
    }
end

#not(operand) ⇒ Object

replacement for ruby’s builtin “not”/“!” operators



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# File 'lib/grammar/ruby.rb', line 62

def not(operand)
    operand._not
end

#or(first, &second) ⇒ Object

replacement for ruby’s builtin “or”/“||” operators



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# File 'lib/grammar/ruby.rb', line 50

def or(first, &second) # :yield:
    first._or(&second)
end

#output(&block) ⇒ Object

:yield: buf[, engine]



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# File 'lib/grammar/ruby.rb', line 264

def output(&block) # :yield: buf[, engine]
    Code::Always.new(
        block_given? ? @output._assign(
            block.arity==1 ? yield(@output) : yield(@output, self)
        ) : @output
    )
end

#pipe(lexer, parser, buf0, max_size = nil, &block) ⇒ Object

:yield: buf[, engine]



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# File 'lib/grammar/ruby.rb', line 636

def pipe(lexer, parser, buf0, max_size=nil, &block) # :yield: buf[, engine]
    raise("TODO")
end

#positive ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 328

def positive # :yield: engine
    consume = @consume
    @consume = nil
    begin
        yield(self)
    ensure
        @consume = consume
    end
end

#recurse(inner, expand = false, &outer) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 458

def recurse(inner, expand=false, &outer) # :yield: engine
    inner0 = inner.to_proc
    left = false
    right = false
    right0 = false
    middle = false
    failure = @failure
    followed = @followed
    consumed = @consumed
    nexpected = @expected.size
    inner << proc {
        if @consumed==consumed
            @followed!=followed or raise("something must follow left recursion")
            left = true
            Code::False
        elsif !left && @followed==followed && @failure
            if !failure
                right0 = true
                recurse(inner, true, &outer)
            else
                right = true
                Code::FalseTerminator
            end
        else
            middle = true
            call(inner, &outer)
        end
    }
    body = yield(self)
    if !@consume
        body
    elsif left
        !right or raise("middle recursion should have happened")
        consumed = @consumed
        inner << proc {
            if @consumed==consumed
                @failure = @failure_break
                Code::True
            else
                call(inner, &outer)
            end
        }
        body._and {
            begin
                expected = @expected
                @expected = []
                Code::While.new(Code::True, yield(self))._step(Code::True)
            ensure
                @expected = expected
            end
        }
    elsif right
        Code::Until.new(body)._step(Code::True)
    elsif !expand && (@methods.include?(outer) || !right0)
        n = @expected.size-nexpected
        @expected.slice!(-n, n)
        call(inner, &outer)
    else
        body
    end
ensure
    inner << inner0
end

#redirect(gram, buf0, &block) ⇒ Object

:yield: buf[, engine]



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# File 'lib/grammar/ruby.rb', line 522

def redirect(gram, buf0, &block) # :yield: buf[, engine]
    @consume or return(gram[self])
    output = @output
    consume = @consume
    @followed += 1 if block_given?
    Code::Local.new { |buf|
        begin
            @output = buf
            @consume = true
            output_init = self[buf0,true]
            if @failure
                @output._assign(output_init)._step(gram[self])
            else
                @output_init = output_init
                gram[self]
            end
        ensure
            @followed -= 1 if block_given?
            @output = output
            @consume = consume
        end._and {
            !block_given? ? Code::True :
            (@output_init ? (@output._assign(@output_init)) : Code::True).
            _step(Code::Always.new(
                block.arity==1 ? yield(buf) : yield(buf, self)
            ))
        }
    }
end

#send(obj, method, *args, &block) ⇒ Object

method call. Typically this shouldn’t be needed. obj.method(*args, &block) should be sufficient.



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# File 'lib/grammar/ruby.rb', line 41

def send(obj, method, *args, &block)
    obj.method_missing(method, *args, &block)
end

#send_splat(obj, method, *args, &block) ⇒ Object

method call with the last argument splatted.



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# File 'lib/grammar/ruby.rb', line 45

def send_splat(obj, method, *args, &block)
    args << args.pop._splat
    obj.method_missing(method, *args, &block)
end

#sequence(gram1) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby.rb', line 306

def sequence(gram1) # :yield: engine
    nexpected = @expected.size
    @followed += 1
    begin
        gram1[self]
    ensure
        @followed -= 1
    end._and{
        expected = @expected
        begin
            if expected.size>nexpected
                @expected = []
                @consume ? yield(self) : Code::True
            else
                yield(self)
            end
        ensure
            @expected = expected
        end
    }
end

#steps(*steps) ⇒ Object

replacement for ruby’s builtin “;” operator



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# File 'lib/grammar/ruby.rb', line 58

def steps(*steps)
    steps.inject { |compound,step| compound._step(step) }
end

#supply(tokenizer, parser, buf0, &block) ⇒ Object

:yield: buf[, engine]



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# File 'lib/grammar/ruby.rb', line 571

def supply(tokenizer, parser, buf0, &block) # :yield: buf[, engine]
    @consume or return(Code::True)
    input0 = @input
    lookahead0 = @lookahead
    output0 = @output
    consume0 = @consume
    @followed += 1 if block_given?
    Code::Local.new { |buf,index,input1,lookahead1|
        begin
            Code::Steps.new([
                buf._assign(self[buf0,true]),
                index._assign(Code[-1]),
                input1._assign(Code::Implicit::lambda { ||
                    buf[index._assign(index+Code[1])]._or { steps(
                        buf.slice!(Code[0], buf.size),
                        begin
                            @output = buf
                            @consume = true
                            @expected = []
                            tokenizer[self]
                        ensure
                            @output = output0
                            @consume = consume0
                        end,
                        buf[index._assign(Code[0])]
                    )}
                }),
                lookahead1._assign(input1[]),
                begin
                    @input = input1
                    @lookahead = lookahead1
                    @consume = true
                    @expected = []
                    parser[self]
                ensure
                    @input = input0
                    @lookahead = lookahead0
                    @consume = consume0
                end
            ])
        ensure
            @followed -= 1 if block_given?
        end._and {
            !block_given? ? Code::True :
            steps(
                buf.slice!(Code[0], index+Code[1]),
                buf << lookahead1,
                Code::Always.new(
                    block.arity==1 ? yield(buf) : yield(buf, self)
                )
            )
        }
    }
ensure
    @expected = []
end

#variables(n = nil, &block) ⇒ Object

:yield: *vars



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# File 'lib/grammar/ruby.rb', line 370

def variables(n=nil, &block) # :yield: *vars
    scopes = {}
    visitor = lambda { scopes[@scope] = true }
    vars2 = nil
    Code::Local.new(n||block.arity) { |*vars|
        vars2 = vars
        yield(*vars.map { |var| Var.new(var, visitor) })[self]
    }
ensure
    if scopes.size>1
        vars2.each { |var|
            var._data.replace(assign(Code[nil])._data)
        }
    end
end