15. An apparatus configured to preprocess a netlist description that includes one or more embedded code segments for describing a circuit, the apparatus comprising at least one computer to perform operations that provide: a specification module to specify one or more programming languages to generate netlist code through scripting operations of the one or more programming languages; a scanning module to scan 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; a pipeline-configuration module to configure 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 a pipeline-use module to use 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.
15. An apparatus configured to preprocess a netlist description that includes one or more embedded code segments for describing a circuit, the apparatus comprising at least one computer to perform operations that provide: a specification module to specify one or more programming languages to generate netlist code through scripting operations of the one or more programming languages; a scanning module to scan 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; a pipeline-configuration module to configure 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 a pipeline-use module to use 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. 16. The apparatus of claim 15 , wherein the scripting operations of a first identified programming language include at least one control structure that generates corresponding netlist code by performing a branching operation of the first programming language.