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10.5 Overview of SR stars

The top-level palette is shown in figure 10-1

10.5.1 General stars

Const Output a constantly-present integer output given by the level parameter.
Pre Emit the value of the integer input from the most recent instant in which it was present.
And Emits the logical AND of the two integer inputs, or absent if both inputs are absent.
Add Emit the sum of the two integer inputs, or the value of the present input if the other is absent.
Printer Print the value of each input to the file specified by the fileName state. All inputs are printed on a single line with the prefix in the prefix state.
IntToString Convert the integer input to a string.
StringToInt Convert the string input to an integer.
Sub Emits the different of the two integer inputs, or absent if both inputs are absent.
When When the clock is true, emit the input on the output, otherwise, leave the clock absent.
Mux Depending on the value of the select input, copy either the true input or the false input to the output.

10.5.2 Itcl stars

By default, all of these stars have no behavior. They provide an interface for user-written Itcl scripts that specify their behavior. Each has the following states: itclClassName, the class name of the itcl object associated with the star, itclSourceFile, the path name of the itcl script containing the definition of this class, and itclObjectName, the name of the itcl object to create. If this field is left blank, the object is given the name of the star instance. See the SR chapter in the Programmer's Manual for more information.

ItclOut Single output Itcl star.
ItclIn Single input Itcl star.
ItclInOut One input, one output Itcl star.
ItclCounter Itcl incrementer/decrementer.
ItclModeSelect Itcl star used in the Rolodex demo.
ItclDatabase Simple sorted database.
ItclDisplay Display for the rolodex.
ItclEditor Editor for the rolodex

10.5.3 MIDI stars

The MIDI stars below are used in the MIDISynthesizer demo described later in this chapter. We include these stars only as an example of what can be done with the Synchronous Reactive domain.

SerialIn Emit the character waiting on the serial port, or leave the output absent if there isn't one. The deviceName state specifies the port, and baudRate specifies the speed.
MIDIin An interpreter for the MIDI protocol. It takes an incoming MIDI stream and fans it out to Note On and Note Off commands.
SynthControl A polyphonic synthesizer control.
EnvelopeGen An envelope generator for FM sound synthesis.

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