8. A non-transitory computer-readable medium that stores a computer program for preprocessing a netlist description that includes one or more embedded code segments for describing a circuit, the computer program including instructions that, when executed by a computer, cause the computer to perform operations comprising: specifying one or more programming languages to generate netlist code through scripting operations of the one or more programming languages; scanning the netlist description to identify the one or more embedded code segments and the corresponding programming language of each embedded code segment from the one or more specified programming languages, the embedded code segment generating a preprocessed segment to replace the embedded code segment in the netlist description through the scripting operations of the identified programming language, and the preprocessed segment including at least some netlist code; configuring a pipeline preprocessor to receive the netlist description and sequentially process the netlist description through one or more programming-language preprocessors that correspond to the one or more identified programming languages, each programming-language preprocessor operating on at least one embedded code segment written in its corresponding programming language to generate at least one preprocessed segment that replaces the at least one embedded code segment in the netlist description; and using the pipeline preprocessor to generate a preprocessed netlist description, the one or more embedded code segments being replaced by the one or more preprocessed segments in the preprocessed netlist description.
8. A non-transitory computer-readable medium that stores a computer program for preprocessing a netlist description that includes one or more embedded code segments for describing a circuit, the computer program including instructions that, when executed by a computer, cause the computer to perform operations comprising: specifying one or more programming languages to generate netlist code through scripting operations of the one or more programming languages; scanning the netlist description to identify the one or more embedded code segments and the corresponding programming language of each embedded code segment from the one or more specified programming languages, the embedded code segment generating a preprocessed segment to replace the embedded code segment in the netlist description through the scripting operations of the identified programming language, and the preprocessed segment including at least some netlist code; configuring a pipeline preprocessor to receive the netlist description and sequentially process the netlist description through one or more programming-language preprocessors that correspond to the one or more identified programming languages, each programming-language preprocessor operating on at least one embedded code segment written in its corresponding programming language to generate at least one preprocessed segment that replaces the at least one embedded code segment in the netlist description; and using the pipeline preprocessor to generate a preprocessed netlist description, the one or more embedded code segments being replaced by the one or more preprocessed segments in the preprocessed netlist description. 11. The computer-readable medium of claim 8 , wherein the scripting operations of a first identified programming language include at least one control structure that generates corresponding netlist code by accessing the corresponding netlist code from an external site that is identified by a uniform resource identifier.