When using gEDA to design an electronic circuit, users use the schematic editor, gschem, to choose and place schematic symbols on a schematic page, and connect the pins of the symbols together by drawing nets. The user may add various attributes to symbols, nets or pins to modify how the circuit diagrams should be interpreted. The resulting schematics are then processed with the gnetlist tool to generate a netlist.
This chapter describes the different data types used by the Scheme API to represent gEDA documents (both schematics and symbols), and how they relate to each other.