Class: Grammar::Ruby0

Inherits:
Object
  • Object
show all
Defined in:
lib/grammar/ruby0.rb

Defined Under Namespace

Classes: Error, PipeBuffer, Var, Void

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(output = nil, lookahead = nil, input_buffer = [], error = self.class::Error.new, followed = 0, hold = false, &input) ⇒ Ruby0

Returns a new instance of Ruby0.



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# File 'lib/grammar/ruby0.rb', line 112

def initialize(output=nil, lookahead=nil, input_buffer=[],
               error=self.class::Error.new, followed = 0, hold = false,
               &input)
    @output = output
    @input = input
    @lookahead = lookahead || (input && input[])
    @input_buffer = input_buffer
    @hold = hold
    @followed = followed
    @error = error
end

Instance Attribute Details

#error ⇒ Object (readonly)

these are mainly for internal usage



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# File 'lib/grammar/ruby0.rb', line 45

def error
  @error
end

#input ⇒ Object (readonly)

these are mainly for internal usage



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# File 'lib/grammar/ruby0.rb', line 45

def input
  @input
end

#lookahead ⇒ Object (readonly)

these are mainly for internal usage



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# File 'lib/grammar/ruby0.rb', line 45

def lookahead
  @lookahead
end

Class Method Details

.compile(gram) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 6

def self.compile(gram)
    lambda { |output, input| gram[new(output, &input)] }
end

Instance Method Details

#<<(item) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 37

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

#[](object, clone = false) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 10

def [](object, clone=false)
    clone ? object.clone : object
rescue
    object
end

#alternation(gram1) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 135

def alternation(gram1) # :yield: engine
    raise = @error.noraise
    @followed += 1
    begin
        gram1[self]
    ensure
        @followed -= 1
        raise1 = @error.raise
        @error.raise = raise
    end or yield(self)
ensure
    @error.raise ||= raise1
end

#always {|_self| ... } ⇒ Object

:yield: engine

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/grammar/ruby0.rb', line 205

def always # :yield: engine
    yield(self)
end

#and(first) ⇒ Object

:yield:



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# File 'lib/grammar/ruby0.rb', line 21

def and(first) # :yield:
    first && yield
end

#any ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 199

def any
    @lookahead ? consume : failure("ANY")
end

#backref(gram, &block) ⇒ Object

:yield: n[, engine]



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# File 'lib/grammar/ruby0.rb', line 308

def backref(gram, &block) # :yield: n[, engine] 
    tainted = @output.tainted?
    size0 = @output.taint.size
    @followed += 1 if block_given?
    begin
        ret = gram[self]
    ensure
        @followed -= 1 if block_given?
        n = @output.size-size0
        if @hold || !ret
            @output.slice!(size0, n)
        end
    end or return
    if !@hold && block_given?
        block.arity==1 ? yield(n) : yield(n, self)
    end
    true
ensure
    @output.untaint unless tainted
end

#backtrack(gram, len = nil) ⇒ Object

:yield: n[, engine]



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# File 'lib/grammar/ruby0.rb', line 329

def backtrack(gram, len=nil) # :yield: n[, engine] 
    tainted = @output.tainted?
    return gram[self] if @error.raise
    len ||= -1
    hold = @hold
    lookahead = @lookahead
    error = @error.clone
    buffer = @input_buffer.clone
    size0 = @output.taint.size
    @followed += 1 if block_given?
    begin
        len = -1 if hold
        @hold = false
        input = @input
        len += 1
        @input = lambda {
            begin
                c = input[]
            ensure
                if (len-=1).zero?
                    @input = input
                    buffer = nil
                else
                    buffer << c
                end
            end
        }
        ret = gram[self]
    rescue self.class::Error => err
        @error = err
        raise(err) if !buffer
    ensure
        @followed -= 1 if block_given?
        @hold = hold
        n = @output.size-size0
        if hold || !ret
            if buffer
                error.concat(@error) if !ret
                @lookahead = lookahead
                @error = error
                index = -1
                @input = lambda { buffer[index+=1] || (@input=input)[] }
            end
            @output.slice!(size0, n)
            return ret
        end
    end or return
    if !@hold && block_given?
        block.arity==1 ? yield(n) : yield(n, self)
    end
    true
ensure
    @output.untaint unless tainted
end

#consume ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 188

def consume
    @hold or (
        @error.clear
        @output << @lookahead
        @lookahead = @input[]
        true
    )
end

#discard(gram) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 291

def discard(gram) # :yield: engine
    buf = Void.new
    output = @output
    @followed += 1 if block_given?
    begin
        @output = buf
        gram[self]
    ensure
        @followed -= 1 if block_given?
        @output = output
    end or return
    if !@hold && block_given?
        @output << yield(self)
    end
    true
end

#eof ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 196

def eof
    !@lookahead or failure("EOF")
end

#failure(expected = nil) ⇒ Object

atomic parsing



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# File 'lib/grammar/ruby0.rb', line 185

def failure(expected=nil)
    @error[expected, @lookahead]
end

#fork(buf) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 124

def fork(buf)
    self.class.new(buf, @lookahead, @input_buffer,
                   @error.clone, @followed, @hold, &@input)
end

#if(condition, yes, &no) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 27

def if(condition, yes, &no)
    condition ? yes[] : no[]
end

#join(engine) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 129

def join(engine)
    @input = engine.input
    @lookahead = engine.lookahead
    @error = engine.error
end

#match(pattern) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 202

def match(pattern)
    (pattern===@lookahead) ? consume : failure(pattern)
end

#negative ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 171

def negative # :yield: engine
    hold = @hold
    raise = @error.noraise
    begin
        @hold = true
        not yield(self)
    ensure
        @error.raise = raise
        @hold = hold
    end or failure("something else")
end

#not(operand) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 24

def not(operand)
    !operand
end

#or(first) ⇒ Object

:yield:



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# File 'lib/grammar/ruby0.rb', line 18

def or(first) # :yield:
    first || yield
end

#output ⇒ Object

:yield: buf



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# File 'lib/grammar/ruby0.rb', line 40

def output # :yield: buf
    block_given? ? (@output = yield(@output)) : @output
end

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

:yield: buf[, engine]



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# File 'lib/grammar/ruby0.rb', line 454

def pipe(lexer, parser, buf0, max_size=nil) # :yield: buf[, engine] 
    !@hold or raise("can't hold pipe")
    buf = buf0.clone
    mutex = Mutex.new
    cvar = ConditionVariable.new
    pbuf = PipeBuffer.new(buf, mutex, cvar, max_size)
    engine = fork(pbuf)
    producer = Thread.new {
        begin
            lexer[engine]
        ensure
            mutex.lock
            cvar.signal
            cvar = nil
            mutex.unlock
        end
    }
    @followed += 1 if block_given?
    begin
        index = 0
        @input = lambda {
            mutex.lock
            begin
                buf[index]
            ensure
                begin
                    if 2*(index+=1)>buf.size
                        buf.slice!(0, index)
                        index = 0
                    end
                    if cvar
                        cvar.signal
                        cvar.wait(mutex) if buf.empty?
                    end
                ensure
                    mutex.unlock
                end
            end
        }
        mutex.lock
        #mutex.sleep if buf.empty?
        cvar.wait(mutex) if cvar && buf.empty?
        mutex.unlock
        @lookahead = input[]
        parser[self]
    ensure
        @followed -= 1 if block_given?
        mutex.lock
        if cvar
            pbuf.max_size = 1
            cvar.wait(mutex) unless producer.stop?
            producer.kill
        end
        mutex.unlock
        lookahead = @lookahead
        join(engine)
    end or return
    if block_given?
        buf[0, index] = (buf.class.new << lookahead)
        block.arity==1 ? yield(buf) : yield(buf, self)
    end
    true
end

#positive ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 161

def positive # :yield: engine
    hold = @hold
    begin
        @hold = true
        yield(self)
    ensure
        @hold = hold
    end
end

#recurse(inner, &outer) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 227

def recurse(inner, &outer) # :yield: engine
    inner0 = inner.to_proc
    left = false
    right = false
    lloop = false
    followed = @followed
    consumed = @error.consumed
    inner << Proc.new {
        if @error.consumed==consumed
            @followed!=followed or raise("something must follow left recursion") 
            left = true
            lloop ? (@error.raise = true) : failure(nil)
        elsif @followed==followed
            right = true
            true
        else
            recurse(inner, &outer)
        end
    }
    yield(self) or return
    @hold and return(true)
    while true
        while right
            consumed = @error.consumed
            right = false
            @error.raise = true
            yield(self) or raise("should have raised")
        end
        left or begin
            !lloop or raise("left recursion not first")
            return(true)
        end
        lloop = true
        consumed = @error.consumed
        begin
            yield(self) or raise("should have raised")
        rescue self.class::Error => err
            err.equal?(@error) && err.consumed==consumed or raise(err)
            return(true)
        end
        @error.consumed!=consumed or raise("infinite loop detected")
    end
ensure
    inner << inner0
end

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

:yield: buf[, engine]



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# File 'lib/grammar/ruby0.rb', line 273

def redirect(gram, buf0, &block) # :yield: buf[, engine]
    buf = buf0.clone
    output = @output
    @followed += 1 if block_given?
    begin
        @output = buf
        gram[self]
    ensure
        buf = @output
        @followed -= 1 if block_given?
        @output = output
    end or return
    if !@hold && block_given?
        block.arity==1 ? yield(buf) : yield(buf, self)
    end
    true
end

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



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# File 'lib/grammar/ruby0.rb', line 30

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

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



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# File 'lib/grammar/ruby0.rb', line 33

def send_splat(obj, method, *args, &block)
    args.concat(args.pop)
    obj.__send__(method, *args, &block)
end

#sequence(gram1) ⇒ Object

:yield: engine



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# File 'lib/grammar/ruby0.rb', line 149

def sequence(gram1) # :yield: engine
    @followed += 1
    begin
        gram1[self]
    ensure
        @followed -= 1
    end and begin
        # TODO: keep going with hold if nothing expected yet
        @hold ? true : yield(self)
    end
end

#steps(*steps) ⇒ Object 



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# File 'lib/grammar/ruby0.rb', line 15

def steps(*steps)
    steps[-1]
end

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

:yield: buf[, engine]



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# File 'lib/grammar/ruby0.rb', line 384

def supply(tokenizer, parser, buf0, &block) # :yield: buf[, engine] 
    !@hold or raise("can't hold supply")
    buf = buf0.clone
    engine = fork(buf)
    @followed += 1 if block_given?
    begin
        index = -1
        @input = lambda {
            buf[index+=1] or begin
                buf.slice!(0, buf.size)
                tokenizer[engine]
                buf[index = 0]
            end
        }
        @lookahead = input[]
        parser[self]
    ensure
        @followed -= 1 if block_given?
        lookahead = @lookahead
        join(engine)
    end or return
    if block_given?
        buf.slice!(0, index+1)
        buf << lookahead
        block.arity==1 ? yield(buf) : yield(buf, self)
    end
    true
end

#variables(n = nil, &block) ⇒ Object

:yield: *vars



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# File 'lib/grammar/ruby0.rb', line 222

def variables(n=nil, &block) # :yield: *vars
    vars = (0...(n||block.arity)).map { Var.new }
    yield(*vars)[self]
end