Pure Data is a real-time visual dataflow language where connected boxes replace text code

Pure Data (Pd) is a graphical programming environment for audio: instead of typing text code, you place small boxes on a canvas and connect them with lines (‘cables’) that carry data between them, echoing the patch cables of an analog studio. Because it is datastream-oriented, the flow of data through the connections is the program. Its defining property is real-time operation: unlike text languages that must be compiled/run before you hear a result, edits in Pd take effect during performance, so you hear changes instantly - which is what makes it suited to live use. Pd was created by Miller Puckette (who also co-developed Max/MSP) and is open source.

Examples

Two objects wired together form the smallest patch: osc~ 440 -> dac~ produces a 440 Hz sine at the speakers, live-editable while it sounds.

Assessment

Explain why Pd is called a ‘datastream-oriented’ language and what ‘real-time’ buys a performer that a compile-run text language does not.