1. A non-transitory computer-accessible memory medium that stores program instructions executable by a computer system to perform: providing a graphical program development environment comprising a graphical specification and constraint language that allows specification of a model of computation and explicit declaration of constraints; and creating a graphical program in the graphical specification and constraint language in response to user input, wherein the graphical program comprises: a specified model of computation; a plurality of interconnected functional blocks that visually indicate functionality of the graphical program in accordance with the specified model of computation; and graphically indicated specifications or constraints for at least one of the functional blocks in the graphical program; wherein the specifications or constraints comprise: input count (IC), comprising a number of tokens consumed at an input terminal of the at least one functional block by one firing of the at least one functional block; output count (OC), comprising a number of tokens produced at an output terminal of the at least one functional block by one firing of the at least one functional block; execution time (ET), comprising a number of cycles needed by the at least one functional block to complete firing; initiation interval (II), comprising a minimum number of cycles between firings of the at least one functional block; input pattern (IP), comprising a sequence of Boolean values of length at most II, wherein the sequence of Boolean values aligns with the beginning of firing of the at least one functional block, wherein each true value in the sequence denotes consumption of a token at an input terminal of the at least one functional block; and output pattern (OP), comprising a sequence of Boolean values of length at most II, wherein the sequence of Boolean values aligns with the end of firing of the at least one functional block, wherein each true value in the sequence denotes production of a token at an output terminal of the at least one functional block; and automatically generating a program based on the graphical program, wherein the program implements the functionality of the graphical program in accordance with the specified model of computation, and further implements the specifications or constraints; wherein the program is useable to configure a programmable hardware element to perform the functionality subject to the specifications or constraints.
1. A non-transitory computer-accessible memory medium that stores program instructions executable by a computer system to perform: providing a graphical program development environment comprising a graphical specification and constraint language that allows specification of a model of computation and explicit declaration of constraints; and creating a graphical program in the graphical specification and constraint language in response to user input, wherein the graphical program comprises: a specified model of computation; a plurality of interconnected functional blocks that visually indicate functionality of the graphical program in accordance with the specified model of computation; and graphically indicated specifications or constraints for at least one of the functional blocks in the graphical program; wherein the specifications or constraints comprise: input count (IC), comprising a number of tokens consumed at an input terminal of the at least one functional block by one firing of the at least one functional block; output count (OC), comprising a number of tokens produced at an output terminal of the at least one functional block by one firing of the at least one functional block; execution time (ET), comprising a number of cycles needed by the at least one functional block to complete firing; initiation interval (II), comprising a minimum number of cycles between firings of the at least one functional block; input pattern (IP), comprising a sequence of Boolean values of length at most II, wherein the sequence of Boolean values aligns with the beginning of firing of the at least one functional block, wherein each true value in the sequence denotes consumption of a token at an input terminal of the at least one functional block; and output pattern (OP), comprising a sequence of Boolean values of length at most II, wherein the sequence of Boolean values aligns with the end of firing of the at least one functional block, wherein each true value in the sequence denotes production of a token at an output terminal of the at least one functional block; and automatically generating a program based on the graphical program, wherein the program implements the functionality of the graphical program in accordance with the specified model of computation, and further implements the specifications or constraints; wherein the program is useable to configure a programmable hardware element to perform the functionality subject to the specifications or constraints. 23. The non-transitory computer-accessible memory medium of claim 1 , wherein the at least one functional block has multiple possible configurations of IC, OC, ET, II, IP, and OP, and wherein the program instructions are further executable to determine a configuration from the possible configurations based on the specifications or constraints of the at least one functional block, of another functional block, or of the graphical program.